Ask The Brewmasters

It's hard not to notice the momentum that NABLABs seem to be gaining and how the popular press continues to report on this rising sector of the market.  It's also hard not to notice discussions about the potentials for pathogens in these beverages.

Like many brewers, my educational journey began in food science.  One of my favorite food science classes while an undergrad at Virginia Tech from 1988-1991 was food microbiology.  Dr. Cameron Hackney, an expert in pathogenic microbes associated with seafood, delivered enthralling lectures about all the nasty bugs found in the food world.  This topic grabbed my attention and turned me into a very cautious consumer.  Over time I relaxed and developed quite the taste for sushi and oysters.  When I became ill at the 2007 CBC in Austin, Texas, I quickly self-diagnosed myself with Vibrio from raw oysters and began pounding electrolytes and taking Imodium, losing only about 36 hours from the conference and a few pounds in ejected stuff from my body!

In the late 1990's, I made a few batches of hard cider over a 3-year period from juice purchased at a great orchard in Marionville, MO.  This was after the Odwalla juice outbreak involving E.coli O157:H7 that sickened 66 people, caused the death of one child, and changed the juice world.  After this outbreak, all juice producers were required to pasteurize juice and many small orchards producing apple juice/cider stopped production because the CAPEX was not worth the squeeze.

As NABLABs continue to grow in popularity, brewers are smart to be cautious of the risks and smart to implement proper practices.  But has the risk been over-stated?  Vibrio is found in unpolluted saltwater and is an obvious organism associated with shellfish.  E.coli is found in animal feces and can contaminant fruits and vegetables.  The Odwalla case was linked to fallen apples picked from the ground, so-called grounders, that were contaminated by deer feces.  Cases of hemorrhagic E.coli in vegetables have been tied to contaminated water used for irrigation.  The same is true of Salmonella outbreaks in fresh produce, like the current cucumber outbreak.  And one of the landmark cases of foodborne listeriosis was tracked to cabbage contaminated with sheep manure used for fertilizer by an organic farmer.

Serious question for this group?  What are likely vectors of E. coli, Listeria, Salmonella, and other pathogens in beer?  It's one thing to inoculate pathogens into beer to determine the potential for danger, but it's also important to understand sources of these bugs.

Following the Odwalla outbreak, FDA mandated single-strength juices be processed with a 5D process (5 log reduction).  Although the government does not tell processors how to do this, they do reference a paper in their industry guidance document. The study referenced is titled "Thermal Inactivation of Stationary-Phase and Acid-Adapted Escherichia coli O157:H7, Salmonella, and Listeria monocytogenes in Fruit Juices" and does provide a recommended process based on D-values of pathogens actually found in fruit juices and involved in outbreaks (we don't have this sort of history in beer).  The 5D process is a staggering 3 seconds at 71.1C - in beer terms that's 2, yes TWO, pasteurization units!  No brewery pasteurizes at such a low level because the purpose of beer pasteurization is the destruction of spoilage organisms that are indeed present at concentrations much higher than 10,000 cfu/mL.  It's important to point out that the D-values used to provide juice process guidance align with recent work from Greg Rachon's group at Campdem BRI.  The authors of this juice study state:

"Considering that it is not likely to find 10^5 pathogens per ml of juice produced under good manufacturing practices and good sanitary plant conditions, this process is very conservative. During an outbreak of salmonellosis from orange juice contaminated with Salmonella Hartford, counts recovered from the juice were below 10 CFU/100 ml of juice (10). Moreover, the process calculation was based on
data for acid-adapted cells; cells that have not adapted to a stress shock would be more sensitive."

"Shelf-stable, hot-filled juices are processed to inactivate microorganisms such as molds, yeasts, and other bacteria that may spoil the product. A typical pasteurization process might be 90C for 2 s, followed by filling at 85C and holding at that temperature for 1 min before cooling. Without taking into account the cumulative lethality during the cooling period, shelf-stable, hot-filled juices receive a lethality sufficient to inactivate 50,000 logs of acid-adapted vegetative pathogens such as E. coli O157:H7, Salmonella, and L. monocytogenes. There is, thus, no question about the microbial safety of these juices."

You may be wondering why the long post.  I'm sitting in Chicago O'Hare on a Saturday afternoon and was enjoying some very nice craft-brewed NA last night in a small brewery in Pittsburgh who is finding lots of success brewing beers to complement their great range of alcoholic beers.  Producing NABLABs is well within the reach of any brewer brewing great beer.  And the thermal process requirements are not rocket science given the right plan of action, proper data collection, and lab testing.

Food for thought!

------------------------------
Ashton Lewis
Manager of Training and Technical Support
RahrBSG
MBAA District Great Plains, Technical Chair
Springfield, Missouri
(417) 830-2337
------------------------------

I don't know enough about the science behind this to add anything significant to the conversation here, but I'd love to hear some more discussion on this topic -- thanks for starting the conversation, Ashton!

For non-Ohio folks, Ashton and his colleague Grant McDonough gave a pretty fascinating talk on this topic at the Ohio Craft Brewers Conference this year. It made me realize there's a lot more space for practical research that has not been done yet in this field: https://www.youtube.com/watch?v=YrJdQNewe2M

It's hard not to notice the momentum that NABLABs seem to be gaining and how the popular press continues to report on this rising sector of the market.  It's also hard not to notice discussions about the potentials for pathogens in these beverages.

Like many brewers, my educational journey began in food science.  One of my favorite food science classes while an undergrad at Virginia Tech from 1988-1991 was food microbiology.  Dr. Cameron Hackney, an expert in pathogenic microbes associated with seafood, delivered enthralling lectures about all the nasty bugs found in the food world.  This topic grabbed my attention and turned me into a very cautious consumer.  Over time I relaxed and developed quite the taste for sushi and oysters.  When I became ill at the 2007 CBC in Austin, Texas, I quickly self-diagnosed myself with Vibrio from raw oysters and began pounding electrolytes and taking Imodium, losing only about 36 hours from the conference and a few pounds in ejected stuff from my body!

In the late 1990's, I made a few batches of hard cider over a 3-year period from juice purchased at a great orchard in Marionville, MO.  This was after the Odwalla juice outbreak involving E.coli O157:H7 that sickened 66 people, caused the death of one child, and changed the juice world.  After this outbreak, all juice producers were required to pasteurize juice and many small orchards producing apple juice/cider stopped production because the CAPEX was not worth the squeeze.

As NABLABs continue to grow in popularity, brewers are smart to be cautious of the risks and smart to implement proper practices.  But has the risk been over-stated?  Vibrio is found in unpolluted saltwater and is an obvious organism associated with shellfish.  E.coli is found in animal feces and can contaminant fruits and vegetables.  The Odwalla case was linked to fallen apples picked from the ground, so-called grounders, that were contaminated by deer feces.  Cases of hemorrhagic E.coli in vegetables have been tied to contaminated water used for irrigation.  The same is true of Salmonella outbreaks in fresh produce, like the current cucumber outbreak.  And one of the landmark cases of foodborne listeriosis was tracked to cabbage contaminated with sheep manure used for fertilizer by an organic farmer.

Serious question for this group?  What are likely vectors of E. coli, Listeria, Salmonella, and other pathogens in beer?  It's one thing to inoculate pathogens into beer to determine the potential for danger, but it's also important to understand sources of these bugs.

Following the Odwalla outbreak, FDA mandated single-strength juices be processed with a 5D process (5 log reduction).  Although the government does not tell processors how to do this, they do reference a paper in their industry guidance document. The study referenced is titled "Thermal Inactivation of Stationary-Phase and Acid-Adapted Escherichia coli O157:H7, Salmonella, and Listeria monocytogenes in Fruit Juices" and does provide a recommended process based on D-values of pathogens actually found in fruit juices and involved in outbreaks (we don't have this sort of history in beer).  The 5D process is a staggering 3 seconds at 71.1C - in beer terms that's 2, yes TWO, pasteurization units!  No brewery pasteurizes at such a low level because the purpose of beer pasteurization is the destruction of spoilage organisms that are indeed present at concentrations much higher than 10,000 cfu/mL.  It's important to point out that the D-values used to provide juice process guidance align with recent work from Greg Rachon's group at Campdem BRI.  The authors of this juice study state:

"Considering that it is not likely to find 10^5 pathogens per ml of juice produced under good manufacturing practices and good sanitary plant conditions, this process is very conservative. During an outbreak of salmonellosis from orange juice contaminated with Salmonella Hartford, counts recovered from the juice were below 10 CFU/100 ml of juice (10). Moreover, the process calculation was based on
data for acid-adapted cells; cells that have not adapted to a stress shock would be more sensitive."

"Shelf-stable, hot-filled juices are processed to inactivate microorganisms such as molds, yeasts, and other bacteria that may spoil the product. A typical pasteurization process might be 90C for 2 s, followed by filling at 85C and holding at that temperature for 1 min before cooling. Without taking into account the cumulative lethality during the cooling period, shelf-stable, hot-filled juices receive a lethality sufficient to inactivate 50,000 logs of acid-adapted vegetative pathogens such as E. coli O157:H7, Salmonella, and L. monocytogenes. There is, thus, no question about the microbial safety of these juices."

You may be wondering why the long post.  I'm sitting in Chicago O'Hare on a Saturday afternoon and was enjoying some very nice craft-brewed NA last night in a small brewery in Pittsburgh who is finding lots of success brewing beers to complement their great range of alcoholic beers.  Producing NABLABs is well within the reach of any brewer brewing great beer.  And the thermal process requirements are not rocket science given the right plan of action, proper data collection, and lab testing.

Food for thought!

------------------------------
Ashton Lewis
Manager of Training and Technical Support
RahrBSG
MBAA District Great Plains, Technical Chair
Springfield, Missouri
(417) 830-2337
------------------------------

It's hard not to notice the momentum that NABLABs seem to be gaining and how the popular press continues to report on this rising sector of the market.  It's also hard not to notice discussions about the potentials for pathogens in these beverages.

Like many brewers, my educational journey began in food science.  One of my favorite food science classes while an undergrad at Virginia Tech from 1988-1991 was food microbiology.  Dr. Cameron Hackney, an expert in pathogenic microbes associated with seafood, delivered enthralling lectures about all the nasty bugs found in the food world.  This topic grabbed my attention and turned me into a very cautious consumer.  Over time I relaxed and developed quite the taste for sushi and oysters.  When I became ill at the 2007 CBC in Austin, Texas, I quickly self-diagnosed myself with Vibrio from raw oysters and began pounding electrolytes and taking Imodium, losing only about 36 hours from the conference and a few pounds in ejected stuff from my body!

In the late 1990's, I made a few batches of hard cider over a 3-year period from juice purchased at a great orchard in Marionville, MO.  This was after the Odwalla juice outbreak involving E.coli O157:H7 that sickened 66 people, caused the death of one child, and changed the juice world.  After this outbreak, all juice producers were required to pasteurize juice and many small orchards producing apple juice/cider stopped production because the CAPEX was not worth the squeeze.

As NABLABs continue to grow in popularity, brewers are smart to be cautious of the risks and smart to implement proper practices.  But has the risk been over-stated?  Vibrio is found in unpolluted saltwater and is an obvious organism associated with shellfish.  E.coli is found in animal feces and can contaminant fruits and vegetables.  The Odwalla case was linked to fallen apples picked from the ground, so-called grounders, that were contaminated by deer feces.  Cases of hemorrhagic E.coli in vegetables have been tied to contaminated water used for irrigation.  The same is true of Salmonella outbreaks in fresh produce, like the current cucumber outbreak.  And one of the landmark cases of foodborne listeriosis was tracked to cabbage contaminated with sheep manure used for fertilizer by an organic farmer.

Serious question for this group?  What are likely vectors of E. coli, Listeria, Salmonella, and other pathogens in beer?  It's one thing to inoculate pathogens into beer to determine the potential for danger, but it's also important to understand sources of these bugs.

Following the Odwalla outbreak, FDA mandated single-strength juices be processed with a 5D process (5 log reduction).  Although the government does not tell processors how to do this, they do reference a paper in their industry guidance document. The study referenced is titled "Thermal Inactivation of Stationary-Phase and Acid-Adapted Escherichia coli O157:H7, Salmonella, and Listeria monocytogenes in Fruit Juices" and does provide a recommended process based on D-values of pathogens actually found in fruit juices and involved in outbreaks (we don't have this sort of history in beer).  The 5D process is a staggering 3 seconds at 71.1C - in beer terms that's 2, yes TWO, pasteurization units!  No brewery pasteurizes at such a low level because the purpose of beer pasteurization is the destruction of spoilage organisms that are indeed present at concentrations much higher than 10,000 cfu/mL.  It's important to point out that the D-values used to provide juice process guidance align with recent work from Greg Rachon's group at Campdem BRI.  The authors of this juice study state:

"Considering that it is not likely to find 10^5 pathogens per ml of juice produced under good manufacturing practices and good sanitary plant conditions, this process is very conservative. During an outbreak of salmonellosis from orange juice contaminated with Salmonella Hartford, counts recovered from the juice were below 10 CFU/100 ml of juice (10). Moreover, the process calculation was based on
data for acid-adapted cells; cells that have not adapted to a stress shock would be more sensitive."

"Shelf-stable, hot-filled juices are processed to inactivate microorganisms such as molds, yeasts, and other bacteria that may spoil the product. A typical pasteurization process might be 90C for 2 s, followed by filling at 85C and holding at that temperature for 1 min before cooling. Without taking into account the cumulative lethality during the cooling period, shelf-stable, hot-filled juices receive a lethality sufficient to inactivate 50,000 logs of acid-adapted vegetative pathogens such as E. coli O157:H7, Salmonella, and L. monocytogenes. There is, thus, no question about the microbial safety of these juices."

You may be wondering why the long post.  I'm sitting in Chicago O'Hare on a Saturday afternoon and was enjoying some very nice craft-brewed NA last night in a small brewery in Pittsburgh who is finding lots of success brewing beers to complement their great range of alcoholic beers.  Producing NABLABs is well within the reach of any brewer brewing great beer.  And the thermal process requirements are not rocket science given the right plan of action, proper data collection, and lab testing.

Food for thought!

------------------------------
Ashton Lewis
Manager of Training and Technical Support
RahrBSG
MBAA District Great Plains, Technical Chair
Springfield, Missouri
(417) 830-2337
------------------------------

It's hard not to notice the momentum that NABLABs seem to be gaining and how the popular press continues to report on this rising sector of the market.  It's also hard not to notice discussions about the potentials for pathogens in these beverages.

Like many brewers, my educational journey began in food science.  One of my favorite food science classes while an undergrad at Virginia Tech from 1988-1991 was food microbiology.  Dr. Cameron Hackney, an expert in pathogenic microbes associated with seafood, delivered enthralling lectures about all the nasty bugs found in the food world.  This topic grabbed my attention and turned me into a very cautious consumer.  Over time I relaxed and developed quite the taste for sushi and oysters.  When I became ill at the 2007 CBC in Austin, Texas, I quickly self-diagnosed myself with Vibrio from raw oysters and began pounding electrolytes and taking Imodium, losing only about 36 hours from the conference and a few pounds in ejected stuff from my body!

In the late 1990's, I made a few batches of hard cider over a 3-year period from juice purchased at a great orchard in Marionville, MO.  This was after the Odwalla juice outbreak involving E.coli O157:H7 that sickened 66 people, caused the death of one child, and changed the juice world.  After this outbreak, all juice producers were required to pasteurize juice and many small orchards producing apple juice/cider stopped production because the CAPEX was not worth the squeeze.

As NABLABs continue to grow in popularity, brewers are smart to be cautious of the risks and smart to implement proper practices.  But has the risk been over-stated?  Vibrio is found in unpolluted saltwater and is an obvious organism associated with shellfish.  E.coli is found in animal feces and can contaminant fruits and vegetables.  The Odwalla case was linked to fallen apples picked from the ground, so-called grounders, that were contaminated by deer feces.  Cases of hemorrhagic E.coli in vegetables have been tied to contaminated water used for irrigation.  The same is true of Salmonella outbreaks in fresh produce, like the current cucumber outbreak.  And one of the landmark cases of foodborne listeriosis was tracked to cabbage contaminated with sheep manure used for fertilizer by an organic farmer.

Serious question for this group?  What are likely vectors of E. coli, Listeria, Salmonella, and other pathogens in beer?  It's one thing to inoculate pathogens into beer to determine the potential for danger, but it's also important to understand sources of these bugs.

Following the Odwalla outbreak, FDA mandated single-strength juices be processed with a 5D process (5 log reduction).  Although the government does not tell processors how to do this, they do reference a paper in their industry guidance document. The study referenced is titled "Thermal Inactivation of Stationary-Phase and Acid-Adapted Escherichia coli O157:H7, Salmonella, and Listeria monocytogenes in Fruit Juices" and does provide a recommended process based on D-values of pathogens actually found in fruit juices and involved in outbreaks (we don't have this sort of history in beer).  The 5D process is a staggering 3 seconds at 71.1C - in beer terms that's 2, yes TWO, pasteurization units!  No brewery pasteurizes at such a low level because the purpose of beer pasteurization is the destruction of spoilage organisms that are indeed present at concentrations much higher than 10,000 cfu/mL.  It's important to point out that the D-values used to provide juice process guidance align with recent work from Greg Rachon's group at Campden  BRI.  The authors of this juice study state:

"Considering that it is not likely to find 10^5 pathogens per ml of juice produced under good manufacturing practices and good sanitary plant conditions, this process is very conservative. During an outbreak of salmonellosis from orange juice contaminated with Salmonella Hartford, counts recovered from the juice were below 10 CFU/100 ml of juice (10). Moreover, the process calculation was based on
data for acid-adapted cells; cells that have not adapted to a stress shock would be more sensitive."

"Shelf-stable, hot-filled juices are processed to inactivate microorganisms such as molds, yeasts, and other bacteria that may spoil the product. A typical pasteurization process might be 90C for 2 s, followed by filling at 85C and holding at that temperature for 1 min before cooling. Without taking into account the cumulative lethality during the cooling period, shelf-stable, hot-filled juices receive a lethality sufficient to inactivate 50,000 logs of acid-adapted vegetative pathogens such as E. coli O157:H7, Salmonella, and L. monocytogenes. There is, thus, no question about the microbial safety of these juices."

You may be wondering why the long post.  I'm sitting in Chicago O'Hare on a Saturday afternoon and was enjoying some very nice craft-brewed NA last night in a small brewery in Pittsburgh who is finding lots of success brewing beers to complement their great range of alcoholic beers.  Producing NABLABs is well within the reach of any brewer brewing great beer.  And the thermal process requirements are not rocket science given the right plan of action, proper data collection, and lab testing.

Food for thought!

------------------------------
Ashton Lewis
Manager of Training and Technical Support
RahrBSG
MBAA District Great Plains, Technical Chair
Springfield, Missouri
(417) 830-2337
------------------------------

OK, I will take the bait…

I can think of quite a few ways that we can introduce human pathogens into the brewing process but almost no ways they could stay viable with normal brewing practices.

Brewing raw material being an agricultural product can be exposed to fecal material. That is just the nature of things! Birds in the barley fields ("hark, a lark, flying through the park…splat"), birds and other animals in perlite, diatomaceous earth and gypsum mining operations. I certainly have seen open belt conveyors in maltings (though disappearing thankfully) and who is to say what may fly over or crawl across them on occasion? What almost all of these raw materials have in common before being delivered to the brewery is some sort of heat treatment. Malt has kilning. For perlite and DE while they are used in the cold block both of them go through an intensive heating step for preparation. Perlite to expand the structure (like popcorn) and DE with calcining which is intense heat to melt the structure to attain a desired grade. Of course, any ingredient used in the brewhouse before whirlpool goes through boiling and then whirlpool additions are seeing typically ~90C pasteurization step. That covers us for gypsum use assuming used in the kettle or before. Dry-hopping with hops is interesting as I suspect the kilning temperatures for hops may not be enough to fully kill all the potential E-coli but I have no evidence to support that assumption. That being said, I would be surprised that levels in the hops themselves would be a concern even if viable. Then we have the excellent work Greg Rachon and BRI has done recently to help set us at ease in regards to the viability of this bacteria in beer of all types.

I think the focus on human pathogens misses the main point. There are other bacteria that can negatively impact our consumers and thus can create a real or at least a perceived issues with the products we make. Non-alcoholic and low alcohol beers can be more challenging to manage these bacteria as we have removed or at least reduced one of our main hurdles (alcohol). Having been a part of a project that needed to determine the correct PU for a new beer-adjacent formulation, challenge testing with a thermophilic bacterium was used. This bacterium is not a beer spoiler and not a human pathogen. The point is, that generally with PU challenge testing we are not even talking about pathogens as the risk in brewing is very small. That being said, there are two groups that we need to be aware of for both regular beers and more so for no alcohol/low alcohol beers (NABLABS) and they are not "pathogens"…

#1 Lactic acid bacteria: some wild strains of lactic acid bacteria produce biogenic amines. Biogenic amines are not good for our bodies and there has been unhealthy levels found in beer with alcohol and also non-alcoholic beer. As a guideline we should have biogenic amines (BA) and polyamines (PA) less than 50 mg/l combined. Also important to note that the levels can increase during ageing in finished package. The good news in a study of 98 alcoholic beers and 16 non-alcoholic beers the non-alcoholic beers did not show a higher rate of BA and PA. It is hard to say what brewing practices were used for the beers. It could be a safe assumption that the NA beer has a higher rate of using heat pasteurization and maybe that is why BA and PA were not an issue but that is simply a guess.

https://onlinelibrary.wiley.com/doi/10.1002/j.2050-0416.2003.tb00141.x

https://onlinelibrary.wiley.com/doi/full/10.1002/jib.31

https://pubmed.ncbi.nlm.nih.gov/34699076/

#2 Bacillus cereus: this facultative anaerobe can produce a tissue-destructive exoenzymes/toxin (hemolysins, phospholipases, and proteases) that can survive the brewing process.  Being a spore former, the spores can also survive the boiling process. This is a bigger issue for cider producers than brewers but anything is possible.

http://www.bccdc.ca/resource-gallery/Documents/Educational Materials/EH/FPS/Dairy/Outbreak_Bacillus_Milk.pdf

https://www.ncbi.nlm.nih.gov/books/NBK459121/

Nguyen AT, Tallent SM. Screening food for Bacillus cereus toxins using whole genome sequencing. Food Microbiol. 2019 Apr;78:164-170

https://www.sciencedirect.com/science/article/pii/S0362028X23062750

Notice, for both of these examples they can appear in alcoholic beverages and non-alcoholic beverages. It is just that non-alcoholic beverages can be more challenging to manage bacteria. For sure I am old school and like to wrap myself in a safety blanket of a 6-log reduction using heat. Is that more than needed…as Ashton has pointed out…for sure! Just know that if you choose a log reduction level less than industry standard then you may have to defend that choice with data in the future. Similar idea in regards to alternative (non-heat) pasteurization techniques. With proper scientific vetting they may be able to give us that same safety margin. The brewer should be careful when using new technologies and be certain they are meeting the industry standard of heat pasteurization or be ready to defend a lower log reduction. If a brewer chooses to use a novel method without proper vetting, not only is the brewer introducing risk to their consumer and to their brand but also risking our craft/industry reputation.

It's hard not to notice the momentum that NABLABs seem to be gaining and how the popular press continues to report on this rising sector of the market.  It's also hard not to notice discussions about the potentials for pathogens in these beverages.

Like many brewers, my educational journey began in food science.  One of my favorite food science classes while an undergrad at Virginia Tech from 1988-1991 was food microbiology.  Dr. Cameron Hackney, an expert in pathogenic microbes associated with seafood, delivered enthralling lectures about all the nasty bugs found in the food world.  This topic grabbed my attention and turned me into a very cautious consumer.  Over time I relaxed and developed quite the taste for sushi and oysters.  When I became ill at the 2007 CBC in Austin, Texas, I quickly self-diagnosed myself with Vibrio from raw oysters and began pounding electrolytes and taking Imodium, losing only about 36 hours from the conference and a few pounds in ejected stuff from my body!

In the late 1990's, I made a few batches of hard cider over a 3-year period from juice purchased at a great orchard in Marionville, MO.  This was after the Odwalla juice outbreak involving E.coli O157:H7 that sickened 66 people, caused the death of one child, and changed the juice world.  After this outbreak, all juice producers were required to pasteurize juice and many small orchards producing apple juice/cider stopped production because the CAPEX was not worth the squeeze.

As NABLABs continue to grow in popularity, brewers are smart to be cautious of the risks and smart to implement proper practices.  But has the risk been over-stated?  Vibrio is found in unpolluted saltwater and is an obvious organism associated with shellfish.  E.coli is found in animal feces and can contaminant fruits and vegetables.  The Odwalla case was linked to fallen apples picked from the ground, so-called grounders, that were contaminated by deer feces.  Cases of hemorrhagic E.coli in vegetables have been tied to contaminated water used for irrigation.  The same is true of Salmonella outbreaks in fresh produce, like the current cucumber outbreak.  And one of the landmark cases of foodborne listeriosis was tracked to cabbage contaminated with sheep manure used for fertilizer by an organic farmer.

Serious question for this group?  What are likely vectors of E. coli, Listeria, Salmonella, and other pathogens in beer?  It's one thing to inoculate pathogens into beer to determine the potential for danger, but it's also important to understand sources of these bugs.

Following the Odwalla outbreak, FDA mandated single-strength juices be processed with a 5D process (5 log reduction).  Although the government does not tell processors how to do this, they do reference a paper in their industry guidance document. The study referenced is titled "Thermal Inactivation of Stationary-Phase and Acid-Adapted Escherichia coli O157:H7, Salmonella, and Listeria monocytogenes in Fruit Juices" and does provide a recommended process based on D-values of pathogens actually found in fruit juices and involved in outbreaks (we don't have this sort of history in beer).  The 5D process is a staggering 3 seconds at 71.1C - in beer terms that's 2, yes TWO, pasteurization units!  No brewery pasteurizes at such a low level because the purpose of beer pasteurization is the destruction of spoilage organisms that are indeed present at concentrations much higher than 10,000 cfu/mL.  It's important to point out that the D-values used to provide juice process guidance align with recent work from Greg Rachon's group at Campdem BRI.  The authors of this juice study state:

"Considering that it is not likely to find 10^5 pathogens per ml of juice produced under good manufacturing practices and good sanitary plant conditions, this process is very conservative. During an outbreak of salmonellosis from orange juice contaminated with Salmonella Hartford, counts recovered from the juice were below 10 CFU/100 ml of juice (10). Moreover, the process calculation was based on
data for acid-adapted cells; cells that have not adapted to a stress shock would be more sensitive."

"Shelf-stable, hot-filled juices are processed to inactivate microorganisms such as molds, yeasts, and other bacteria that may spoil the product. A typical pasteurization process might be 90C for 2 s, followed by filling at 85C and holding at that temperature for 1 min before cooling. Without taking into account the cumulative lethality during the cooling period, shelf-stable, hot-filled juices receive a lethality sufficient to inactivate 50,000 logs of acid-adapted vegetative pathogens such as E. coli O157:H7, Salmonella, and L. monocytogenes. There is, thus, no question about the microbial safety of these juices."

You may be wondering why the long post.  I'm sitting in Chicago O'Hare on a Saturday afternoon and was enjoying some very nice craft-brewed NA last night in a small brewery in Pittsburgh who is finding lots of success brewing beers to complement their great range of alcoholic beers.  Producing NABLABs is well within the reach of any brewer brewing great beer.  And the thermal process requirements are not rocket science given the right plan of action, proper data collection, and lab testing.

Food for thought!

------------------------------
Ashton Lewis
Manager of Training and Technical Support
RahrBSG
MBAA District Great Plains, Technical Chair
Springfield, Missouri
(417) 830-2337
------------------------------

Lots of great stuff here from Ashton and Travis, and thanks to others here contributing to this important discussion. Since it was not mentioned yet, I want to call out a significant difference between tunnel and flash pasteurization. With NA beverages, flash pasteurization is not enough, there is plenty of opportunity for bugs to get in during the filling process. Non-hot fill packages of NA/LA beverages must undergo tunnel (or batch) pasteurization after the filling process. Kegs and draught dispense? Forget it, can't send those through a tunnel! pH should also be mentioned, under 4.5 please. Other strategies include sterile filtration just upstream of filling plus tunnel pasteurization, a solid one-two punch to micro! Also consider Velcorin, sorbates, sulfites, chiber, etc. If it were me, I'd do all the above!! go ahead, call me paranoid! Cheers!

Jeff

OK, I will take the bait…

I can think of quite a few ways that we can introduce human pathogens into the brewing process but almost no ways they could stay viable with normal brewing practices.

Brewing raw material being an agricultural product can be exposed to fecal material. That is just the nature of things! Birds in the barley fields ("hark, a lark, flying through the park…splat"), birds and other animals in perlite, diatomaceous earth and gypsum mining operations. I certainly have seen open belt conveyors in maltings (though disappearing thankfully) and who is to say what may fly over or crawl across them on occasion? What almost all of these raw materials have in common before being delivered to the brewery is some sort of heat treatment. Malt has kilning. For perlite and DE while they are used in the cold block both of them go through an intensive heating step for preparation. Perlite to expand the structure (like popcorn) and DE with calcining which is intense heat to melt the structure to attain a desired grade. Of course, any ingredient used in the brewhouse before whirlpool goes through boiling and then whirlpool additions are seeing typically ~90C pasteurization step. That covers us for gypsum use assuming used in the kettle or before. Dry-hopping with hops is interesting as I suspect the kilning temperatures for hops may not be enough to fully kill all the potential E-coli but I have no evidence to support that assumption. That being said, I would be surprised that levels in the hops themselves would be a concern even if viable. Then we have the excellent work Greg Rachon and BRI has done recently to help set us at ease in regards to the viability of this bacteria in beer of all types.

I think the focus on human pathogens misses the main point. There are other bacteria that can negatively impact our consumers and thus can create a real or at least a perceived issues with the products we make. Non-alcoholic and low alcohol beers can be more challenging to manage these bacteria as we have removed or at least reduced one of our main hurdles (alcohol). Having been a part of a project that needed to determine the correct PU for a new beer-adjacent formulation, challenge testing with a thermophilic bacterium was used. This bacterium is not a beer spoiler and not a human pathogen. The point is, that generally with PU challenge testing we are not even talking about pathogens as the risk in brewing is very small. That being said, there are two groups that we need to be aware of for both regular beers and more so for no alcohol/low alcohol beers (NABLABS) and they are not "pathogens"…

#1 Lactic acid bacteria: some wild strains of lactic acid bacteria produce biogenic amines. Biogenic amines are not good for our bodies and there has been unhealthy levels found in beer with alcohol and also non-alcoholic beer. As a guideline we should have biogenic amines (BA) and polyamines (PA) less than 50 mg/l combined. Also important to note that the levels can increase during ageing in finished package. The good news in a study of 98 alcoholic beers and 16 non-alcoholic beers the non-alcoholic beers did not show a higher rate of BA and PA. It is hard to say what brewing practices were used for the beers. It could be a safe assumption that the NA beer has a higher rate of using heat pasteurization and maybe that is why BA and PA were not an issue but that is simply a guess.

https://onlinelibrary.wiley.com/doi/10.1002/j.2050-0416.2003.tb00141.x

https://onlinelibrary.wiley.com/doi/full/10.1002/jib.31

https://pubmed.ncbi.nlm.nih.gov/34699076/

#2 Bacillus cereus: this facultative anaerobe can produce a tissue-destructive exoenzymes/toxin (hemolysins, phospholipases, and proteases) that can survive the brewing process.  Being a spore former, the spores can also survive the boiling process. This is a bigger issue for cider producers than brewers but anything is possible.

http://www.bccdc.ca/resource-gallery/Documents/Educational Materials/EH/FPS/Dairy/Outbreak_Bacillus_Milk.pdf

https://www.ncbi.nlm.nih.gov/books/NBK459121/

Nguyen AT, Tallent SM. Screening food for Bacillus cereus toxins using whole genome sequencing. Food Microbiol. 2019 Apr;78:164-170

https://www.sciencedirect.com/science/article/pii/S0362028X23062750

Notice, for both of these examples they can appear in alcoholic beverages and non-alcoholic beverages. It is just that non-alcoholic beverages can be more challenging to manage bacteria. For sure I am old school and like to wrap myself in a safety blanket of a 6-log reduction using heat. Is that more than needed…as Ashton has pointed out…for sure! Just know that if you choose a log reduction level less than industry standard then you may have to defend that choice with data in the future. Similar idea in regards to alternative (non-heat) pasteurization techniques. With proper scientific vetting they may be able to give us that same safety margin. The brewer should be careful when using new technologies and be certain they are meeting the industry standard of heat pasteurization or be ready to defend a lower log reduction. If a brewer chooses to use a novel method without proper vetting, not only is the brewer introducing risk to their consumer and to their brand but also risking our craft/industry reputation.

It's hard not to notice the momentum that NABLABs seem to be gaining and how the popular press continues to report on this rising sector of the market.  It's also hard not to notice discussions about the potentials for pathogens in these beverages.

Like many brewers, my educational journey began in food science.  One of my favorite food science classes while an undergrad at Virginia Tech from 1988-1991 was food microbiology.  Dr. Cameron Hackney, an expert in pathogenic microbes associated with seafood, delivered enthralling lectures about all the nasty bugs found in the food world.  This topic grabbed my attention and turned me into a very cautious consumer.  Over time I relaxed and developed quite the taste for sushi and oysters.  When I became ill at the 2007 CBC in Austin, Texas, I quickly self-diagnosed myself with Vibrio from raw oysters and began pounding electrolytes and taking Imodium, losing only about 36 hours from the conference and a few pounds in ejected stuff from my body!

In the late 1990's, I made a few batches of hard cider over a 3-year period from juice purchased at a great orchard in Marionville, MO.  This was after the Odwalla juice outbreak involving E.coli O157:H7 that sickened 66 people, caused the death of one child, and changed the juice world.  After this outbreak, all juice producers were required to pasteurize juice and many small orchards producing apple juice/cider stopped production because the CAPEX was not worth the squeeze.

As NABLABs continue to grow in popularity, brewers are smart to be cautious of the risks and smart to implement proper practices.  But has the risk been over-stated?  Vibrio is found in unpolluted saltwater and is an obvious organism associated with shellfish.  E.coli is found in animal feces and can contaminant fruits and vegetables.  The Odwalla case was linked to fallen apples picked from the ground, so-called grounders, that were contaminated by deer feces.  Cases of hemorrhagic E.coli in vegetables have been tied to contaminated water used for irrigation.  The same is true of Salmonella outbreaks in fresh produce, like the current cucumber outbreak.  And one of the landmark cases of foodborne listeriosis was tracked to cabbage contaminated with sheep manure used for fertilizer by an organic farmer.

Serious question for this group?  What are likely vectors of E. coli, Listeria, Salmonella, and other pathogens in beer?  It's one thing to inoculate pathogens into beer to determine the potential for danger, but it's also important to understand sources of these bugs.

Following the Odwalla outbreak, FDA mandated single-strength juices be processed with a 5D process (5 log reduction).  Although the government does not tell processors how to do this, they do reference a paper in their industry guidance document. The study referenced is titled "Thermal Inactivation of Stationary-Phase and Acid-Adapted Escherichia coli O157:H7, Salmonella, and Listeria monocytogenes in Fruit Juices" and does provide a recommended process based on D-values of pathogens actually found in fruit juices and involved in outbreaks (we don't have this sort of history in beer).  The 5D process is a staggering 3 seconds at 71.1C - in beer terms that's 2, yes TWO, pasteurization units!  No brewery pasteurizes at such a low level because the purpose of beer pasteurization is the destruction of spoilage organisms that are indeed present at concentrations much higher than 10,000 cfu/mL.  It's important to point out that the D-values used to provide juice process guidance align with recent work from Greg Rachon's group at Campdem BRI.  The authors of this juice study state:

"Considering that it is not likely to find 10^5 pathogens per ml of juice produced under good manufacturing practices and good sanitary plant conditions, this process is very conservative. During an outbreak of salmonellosis from orange juice contaminated with Salmonella Hartford, counts recovered from the juice were below 10 CFU/100 ml of juice (10). Moreover, the process calculation was based on
data for acid-adapted cells; cells that have not adapted to a stress shock would be more sensitive."

"Shelf-stable, hot-filled juices are processed to inactivate microorganisms such as molds, yeasts, and other bacteria that may spoil the product. A typical pasteurization process might be 90C for 2 s, followed by filling at 85C and holding at that temperature for 1 min before cooling. Without taking into account the cumulative lethality during the cooling period, shelf-stable, hot-filled juices receive a lethality sufficient to inactivate 50,000 logs of acid-adapted vegetative pathogens such as E. coli O157:H7, Salmonella, and L. monocytogenes. There is, thus, no question about the microbial safety of these juices."

You may be wondering why the long post.  I'm sitting in Chicago O'Hare on a Saturday afternoon and was enjoying some very nice craft-brewed NA last night in a small brewery in Pittsburgh who is finding lots of success brewing beers to complement their great range of alcoholic beers.  Producing NABLABs is well within the reach of any brewer brewing great beer.  And the thermal process requirements are not rocket science given the right plan of action, proper data collection, and lab testing.

Food for thought!

------------------------------
Ashton Lewis
Manager of Training and Technical Support
RahrBSG
MBAA District Great Plains, Technical Chair
Springfield, Missouri
(417) 830-2337
------------------------------

It's hard not to notice the momentum that NABLABs seem to be gaining and how the popular press continues to report on this rising sector of the market.  It's also hard not to notice discussions about the potentials for pathogens in these beverages.

Like many brewers, my educational journey began in food science.  One of my favorite food science classes while an undergrad at Virginia Tech from 1988-1991 was food microbiology.  Dr. Cameron Hackney, an expert in pathogenic microbes associated with seafood, delivered enthralling lectures about all the nasty bugs found in the food world.  This topic grabbed my attention and turned me into a very cautious consumer.  Over time I relaxed and developed quite the taste for sushi and oysters.  When I became ill at the 2007 CBC in Austin, Texas, I quickly self-diagnosed myself with Vibrio from raw oysters and began pounding electrolytes and taking Imodium, losing only about 36 hours from the conference and a few pounds in ejected stuff from my body!

In the late 1990's, I made a few batches of hard cider over a 3-year period from juice purchased at a great orchard in Marionville, MO.  This was after the Odwalla juice outbreak involving E.coli O157:H7 that sickened 66 people, caused the death of one child, and changed the juice world.  After this outbreak, all juice producers were required to pasteurize juice and many small orchards producing apple juice/cider stopped production because the CAPEX was not worth the squeeze.

As NABLABs continue to grow in popularity, brewers are smart to be cautious of the risks and smart to implement proper practices.  But has the risk been over-stated?  Vibrio is found in unpolluted saltwater and is an obvious organism associated with shellfish.  E.coli is found in animal feces and can contaminant fruits and vegetables.  The Odwalla case was linked to fallen apples picked from the ground, so-called grounders, that were contaminated by deer feces.  Cases of hemorrhagic E.coli in vegetables have been tied to contaminated water used for irrigation.  The same is true of Salmonella outbreaks in fresh produce, like the current cucumber outbreak.  And one of the landmark cases of foodborne listeriosis was tracked to cabbage contaminated with sheep manure used for fertilizer by an organic farmer.

Serious question for this group?  What are likely vectors of E. coli, Listeria, Salmonella, and other pathogens in beer?  It's one thing to inoculate pathogens into beer to determine the potential for danger, but it's also important to understand sources of these bugs.

Following the Odwalla outbreak, FDA mandated single-strength juices be processed with a 5D process (5 log reduction).  Although the government does not tell processors how to do this, they do reference a paper in their industry guidance document. The study referenced is titled "Thermal Inactivation of Stationary-Phase and Acid-Adapted Escherichia coli O157:H7, Salmonella, and Listeria monocytogenes in Fruit Juices" and does provide a recommended process based on D-values of pathogens actually found in fruit juices and involved in outbreaks (we don't have this sort of history in beer).  The 5D process is a staggering 3 seconds at 71.1C - in beer terms that's 2, yes TWO, pasteurization units!  No brewery pasteurizes at such a low level because the purpose of beer pasteurization is the destruction of spoilage organisms that are indeed present at concentrations much higher than 10,000 cfu/mL.  It's important to point out that the D-values used to provide juice process guidance align with recent work from Greg Rachon's group at Campdem BRI.  The authors of this juice study state:

"Considering that it is not likely to find 10^5 pathogens per ml of juice produced under good manufacturing practices and good sanitary plant conditions, this process is very conservative. During an outbreak of salmonellosis from orange juice contaminated with Salmonella Hartford, counts recovered from the juice were below 10 CFU/100 ml of juice (10). Moreover, the process calculation was based on
data for acid-adapted cells; cells that have not adapted to a stress shock would be more sensitive."

"Shelf-stable, hot-filled juices are processed to inactivate microorganisms such as molds, yeasts, and other bacteria that may spoil the product. A typical pasteurization process might be 90C for 2 s, followed by filling at 85C and holding at that temperature for 1 min before cooling. Without taking into account the cumulative lethality during the cooling period, shelf-stable, hot-filled juices receive a lethality sufficient to inactivate 50,000 logs of acid-adapted vegetative pathogens such as E. coli O157:H7, Salmonella, and L. monocytogenes. There is, thus, no question about the microbial safety of these juices."

You may be wondering why the long post.  I'm sitting in Chicago O'Hare on a Saturday afternoon and was enjoying some very nice craft-brewed NA last night in a small brewery in Pittsburgh who is finding lots of success brewing beers to complement their great range of alcoholic beers.  Producing NABLABs is well within the reach of any brewer brewing great beer.  And the thermal process requirements are not rocket science given the right plan of action, proper data collection, and lab testing.

Food for thought!

------------------------------
Ashton Lewis
Manager of Training and Technical Support
RahrBSG
MBAA District Great Plains, Technical Chair
Springfield, Missouri
(417) 830-2337
------------------------------

Great discussions this week about NABLAB safety.  It was indeed my intent to stir the pot with my post and to generate an open dialog.  Although I don't currently work for a brewery and have nothing to gain by promoting NA beer, I do believe it would be beneficial to reframe how many of us may view NA beers.  Because the popular press picked up the Cornell study showing that pathogens can survive in NABLABs under aerobic conditions many brewers and consumers are suspicious of NAs.

Here is a different perspective.

Brewers producing NAs do not want their beers to spoil in the market.  Spoilage is especially concerning to brewers using maltose-negative yeast and to those who add fermentable sugars to their NA products prior to packaging.  For these beers, culture yeast and typical spoilage bacteria are major concerns because these microorganisms are present in breweries and are well-established contaminants in packaged beers that have either been sterile filtered or flash pasteurized before packaging.  In order to protect beer from these common microbes, the standard process is tunnel pasteurize NA beers to protect against refermentation and/or bacterial souring.

The good news is that even the most minimally treated NAs have been exposed to tunnel pasteurization with at least 20 pasteurization units (beer PUs) or the equivalent of 30 seconds at 71.1C.  Twenty beer PUs is 10 times the thermal exposure used by juice processors to satisfy the FDA required process to protect consumers from pathogenic microorganisms found in raw juices, such as E. coli O157:H7, Salmonella, and Listeria.  Twenty beer PUs is also 6 times the thermal exposure (15 seconds at 72C) required to kill Coxiella burnetti and Mycobacterium tuberculosis during milk pasteurization.  Coxiella, the cause of Q-Fever, and Mycobacterium tuberculosis, the cause of tuberculosis, are both transmitted to milk from infected livestock, such as cattle, sheep, and goats.  Unlike fruit juices and milk, preventing pathogenic microorganisms out of beer is an easier proposition.  The easiest way to minimize the risk of introducing pathogens in beer is to not add any ingredient that has not been thermally processed to destroy pathogens to beer after wort cooling.  That means that NA brewers should think about NA beer like food.  No dry hopping or raw fruit additions after cooking, unless there is a process in place to address what these ingredients may bring.

Going back to the FDA industry guidance document for juice processing, the government instructs juice processors to design their 5D process around known or likely pathogens found in juice.  FDA states: "Under the rule, the 5-log reduction must be targeted to the "pertinent pathogen." The "pertinent pathogen" is the most resistant microorganism of public health concern that may occur in the juice. The pertinent pathogen may vary with the type of juice and the type of treatment used, though typically it would be Salmonella or Escherichia coli O157:H7."

The brewing industry, perhaps members of MBAA and ASBC, should identify some targets and get the word out to help brewers go about this with a logical and reasonable approach mirroring the legally mandated processes for milk and juice.

It's hard not to notice the momentum that NABLABs seem to be gaining and how the popular press continues to report on this rising sector of the market.  It's also hard not to notice discussions about the potentials for pathogens in these beverages.

Like many brewers, my educational journey began in food science.  One of my favorite food science classes while an undergrad at Virginia Tech from 1988-1991 was food microbiology.  Dr. Cameron Hackney, an expert in pathogenic microbes associated with seafood, delivered enthralling lectures about all the nasty bugs found in the food world.  This topic grabbed my attention and turned me into a very cautious consumer.  Over time I relaxed and developed quite the taste for sushi and oysters.  When I became ill at the 2007 CBC in Austin, Texas, I quickly self-diagnosed myself with Vibrio from raw oysters and began pounding electrolytes and taking Imodium, losing only about 36 hours from the conference and a few pounds in ejected stuff from my body!

In the late 1990's, I made a few batches of hard cider over a 3-year period from juice purchased at a great orchard in Marionville, MO.  This was after the Odwalla juice outbreak involving E.coli O157:H7 that sickened 66 people, caused the death of one child, and changed the juice world.  After this outbreak, all juice producers were required to pasteurize juice and many small orchards producing apple juice/cider stopped production because the CAPEX was not worth the squeeze.

As NABLABs continue to grow in popularity, brewers are smart to be cautious of the risks and smart to implement proper practices.  But has the risk been over-stated?  Vibrio is found in unpolluted saltwater and is an obvious organism associated with shellfish.  E.coli is found in animal feces and can contaminant fruits and vegetables.  The Odwalla case was linked to fallen apples picked from the ground, so-called grounders, that were contaminated by deer feces.  Cases of hemorrhagic E.coli in vegetables have been tied to contaminated water used for irrigation.  The same is true of Salmonella outbreaks in fresh produce, like the current cucumber outbreak.  And one of the landmark cases of foodborne listeriosis was tracked to cabbage contaminated with sheep manure used for fertilizer by an organic farmer.

Serious question for this group?  What are likely vectors of E. coli, Listeria, Salmonella, and other pathogens in beer?  It's one thing to inoculate pathogens into beer to determine the potential for danger, but it's also important to understand sources of these bugs.

Following the Odwalla outbreak, FDA mandated single-strength juices be processed with a 5D process (5 log reduction).  Although the government does not tell processors how to do this, they do reference a paper in their industry guidance document. The study referenced is titled "Thermal Inactivation of Stationary-Phase and Acid-Adapted Escherichia coli O157:H7, Salmonella, and Listeria monocytogenes in Fruit Juices" and does provide a recommended process based on D-values of pathogens actually found in fruit juices and involved in outbreaks (we don't have this sort of history in beer).  The 5D process is a staggering 3 seconds at 71.1C - in beer terms that's 2, yes TWO, pasteurization units!  No brewery pasteurizes at such a low level because the purpose of beer pasteurization is the destruction of spoilage organisms that are indeed present at concentrations much higher than 10,000 cfu/mL.  It's important to point out that the D-values used to provide juice process guidance align with recent work from Greg Rachon's group at Campdem BRI.  The authors of this juice study state:

"Considering that it is not likely to find 10^5 pathogens per ml of juice produced under good manufacturing practices and good sanitary plant conditions, this process is very conservative. During an outbreak of salmonellosis from orange juice contaminated with Salmonella Hartford, counts recovered from the juice were below 10 CFU/100 ml of juice (10). Moreover, the process calculation was based on
data for acid-adapted cells; cells that have not adapted to a stress shock would be more sensitive."

"Shelf-stable, hot-filled juices are processed to inactivate microorganisms such as molds, yeasts, and other bacteria that may spoil the product. A typical pasteurization process might be 90C for 2 s, followed by filling at 85C and holding at that temperature for 1 min before cooling. Without taking into account the cumulative lethality during the cooling period, shelf-stable, hot-filled juices receive a lethality sufficient to inactivate 50,000 logs of acid-adapted vegetative pathogens such as E. coli O157:H7, Salmonella, and L. monocytogenes. There is, thus, no question about the microbial safety of these juices."

You may be wondering why the long post.  I'm sitting in Chicago O'Hare on a Saturday afternoon and was enjoying some very nice craft-brewed NA last night in a small brewery in Pittsburgh who is finding lots of success brewing beers to complement their great range of alcoholic beers.  Producing NABLABs is well within the reach of any brewer brewing great beer.  And the thermal process requirements are not rocket science given the right plan of action, proper data collection, and lab testing.

Food for thought!

------------------------------
Ashton Lewis
Manager of Training and Technical Support
RahrBSG
MBAA District Great Plains, Technical Chair
Springfield, Missouri
(417) 830-2337
------------------------------

The YouTube recording was really interesting...are the slides posted anywhere?  or may I get a copy of them?

Cheers

Ben

Great discussions this week about NABLAB safety.  It was indeed my intent to stir the pot with my post and to generate an open dialog.  Although I don't currently work for a brewery and have nothing to gain by promoting NA beer, I do believe it would be beneficial to reframe how many of us may view NA beers.  Because the popular press picked up the Cornell study showing that pathogens can survive in NABLABs under aerobic conditions many brewers and consumers are suspicious of NAs.

Here is a different perspective.

Brewers producing NAs do not want their beers to spoil in the market.  Spoilage is especially concerning to brewers using maltose-negative yeast and to those who add fermentable sugars to their NA products prior to packaging.  For these beers, culture yeast and typical spoilage bacteria are major concerns because these microorganisms are present in breweries and are well-established contaminants in packaged beers that have either been sterile filtered or flash pasteurized before packaging.  In order to protect beer from these common microbes, the standard process is tunnel pasteurize NA beers to protect against refermentation and/or bacterial souring.

The good news is that even the most minimally treated NAs have been exposed to tunnel pasteurization with at least 20 pasteurization units (beer PUs) or the equivalent of 30 seconds at 71.1C.  Twenty beer PUs is 10 times the thermal exposure used by juice processors to satisfy the FDA required process to protect consumers from pathogenic microorganisms found in raw juices, such as E. coli O157:H7, Salmonella, and Listeria.  Twenty beer PUs is also 6 times the thermal exposure (15 seconds at 72C) required to kill Coxiella burnetti and Mycobacterium tuberculosis during milk pasteurization.  Coxiella, the cause of Q-Fever, and Mycobacterium tuberculosis, the cause of tuberculosis, are both transmitted to milk from infected livestock, such as cattle, sheep, and goats.  Unlike fruit juices and milk, preventing pathogenic microorganisms out of beer is an easier proposition.  The easiest way to minimize the risk of introducing pathogens in beer is to not add any ingredient that has not been thermally processed to destroy pathogens to beer after wort cooling.  That means that NA brewers should think about NA beer like food.  No dry hopping or raw fruit additions after cooking, unless there is a process in place to address what these ingredients may bring.

Going back to the FDA industry guidance document for juice processing, the government instructs juice processors to design their 5D process around known or likely pathogens found in juice.  FDA states: "Under the rule, the 5-log reduction must be targeted to the "pertinent pathogen." The "pertinent pathogen" is the most resistant microorganism of public health concern that may occur in the juice. The pertinent pathogen may vary with the type of juice and the type of treatment used, though typically it would be Salmonella or Escherichia coli O157:H7."

The brewing industry, perhaps members of MBAA and ASBC, should identify some targets and get the word out to help brewers go about this with a logical and reasonable approach mirroring the legally mandated processes for milk and juice.

It's hard not to notice the momentum that NABLABs seem to be gaining and how the popular press continues to report on this rising sector of the market.  It's also hard not to notice discussions about the potentials for pathogens in these beverages.

Like many brewers, my educational journey began in food science.  One of my favorite food science classes while an undergrad at Virginia Tech from 1988-1991 was food microbiology.  Dr. Cameron Hackney, an expert in pathogenic microbes associated with seafood, delivered enthralling lectures about all the nasty bugs found in the food world.  This topic grabbed my attention and turned me into a very cautious consumer.  Over time I relaxed and developed quite the taste for sushi and oysters.  When I became ill at the 2007 CBC in Austin, Texas, I quickly self-diagnosed myself with Vibrio from raw oysters and began pounding electrolytes and taking Imodium, losing only about 36 hours from the conference and a few pounds in ejected stuff from my body!

In the late 1990's, I made a few batches of hard cider over a 3-year period from juice purchased at a great orchard in Marionville, MO.  This was after the Odwalla juice outbreak involving E.coli O157:H7 that sickened 66 people, caused the death of one child, and changed the juice world.  After this outbreak, all juice producers were required to pasteurize juice and many small orchards producing apple juice/cider stopped production because the CAPEX was not worth the squeeze.

As NABLABs continue to grow in popularity, brewers are smart to be cautious of the risks and smart to implement proper practices.  But has the risk been over-stated?  Vibrio is found in unpolluted saltwater and is an obvious organism associated with shellfish.  E.coli is found in animal feces and can contaminant fruits and vegetables.  The Odwalla case was linked to fallen apples picked from the ground, so-called grounders, that were contaminated by deer feces.  Cases of hemorrhagic E.coli in vegetables have been tied to contaminated water used for irrigation.  The same is true of Salmonella outbreaks in fresh produce, like the current cucumber outbreak.  And one of the landmark cases of foodborne listeriosis was tracked to cabbage contaminated with sheep manure used for fertilizer by an organic farmer.

Serious question for this group?  What are likely vectors of E. coli, Listeria, Salmonella, and other pathogens in beer?  It's one thing to inoculate pathogens into beer to determine the potential for danger, but it's also important to understand sources of these bugs.

Following the Odwalla outbreak, FDA mandated single-strength juices be processed with a 5D process (5 log reduction).  Although the government does not tell processors how to do this, they do reference a paper in their industry guidance document. The study referenced is titled "Thermal Inactivation of Stationary-Phase and Acid-Adapted Escherichia coli O157:H7, Salmonella, and Listeria monocytogenes in Fruit Juices" and does provide a recommended process based on D-values of pathogens actually found in fruit juices and involved in outbreaks (we don't have this sort of history in beer).  The 5D process is a staggering 3 seconds at 71.1C - in beer terms that's 2, yes TWO, pasteurization units!  No brewery pasteurizes at such a low level because the purpose of beer pasteurization is the destruction of spoilage organisms that are indeed present at concentrations much higher than 10,000 cfu/mL.  It's important to point out that the D-values used to provide juice process guidance align with recent work from Greg Rachon's group at Campdem BRI.  The authors of this juice study state:

"Considering that it is not likely to find 10^5 pathogens per ml of juice produced under good manufacturing practices and good sanitary plant conditions, this process is very conservative. During an outbreak of salmonellosis from orange juice contaminated with Salmonella Hartford, counts recovered from the juice were below 10 CFU/100 ml of juice (10). Moreover, the process calculation was based on
data for acid-adapted cells; cells that have not adapted to a stress shock would be more sensitive."

"Shelf-stable, hot-filled juices are processed to inactivate microorganisms such as molds, yeasts, and other bacteria that may spoil the product. A typical pasteurization process might be 90C for 2 s, followed by filling at 85C and holding at that temperature for 1 min before cooling. Without taking into account the cumulative lethality during the cooling period, shelf-stable, hot-filled juices receive a lethality sufficient to inactivate 50,000 logs of acid-adapted vegetative pathogens such as E. coli O157:H7, Salmonella, and L. monocytogenes. There is, thus, no question about the microbial safety of these juices."

You may be wondering why the long post.  I'm sitting in Chicago O'Hare on a Saturday afternoon and was enjoying some very nice craft-brewed NA last night in a small brewery in Pittsburgh who is finding lots of success brewing beers to complement their great range of alcoholic beers.  Producing NABLABs is well within the reach of any brewer brewing great beer.  And the thermal process requirements are not rocket science given the right plan of action, proper data collection, and lab testing.

Food for thought!

------------------------------
Ashton Lewis
Manager of Training and Technical Support
RahrBSG
MBAA District Great Plains, Technical Chair
Springfield, Missouri
(417) 830-2337
------------------------------