Microbial Stability in Draft NA

It is near-universally agreed that NA beer packaging requires pasteurization for microbiological stability. This includes both aerobic and anaerobic beer spoilers, as well as pathogenic bacteria like E. coli and Salmonella. 

Some of the consequences of this include breweries holding off on developing NA brands until they can figure out a route to pasteurization, which may require significant capital investment for flash and tunnel pasteurizers, or logistical complications from pasteurizing off-site. In any case, it becomes a real barrier to entry in the NA space.

And where does NA draft fall in all this? Since kegs cannot currently be feasibly tunnel pasteurized, they’re left more exposed than smaller packages. Flash pasteurization or sterile filtration are still options, which are good for protection up until the fill. But neither ensures protection during fill and once in the keg, not to mention after it leaves the facility and gets into the hands of distributors and, later, bars and taprooms, where hygienic practices are concerningly varied.

This concern isn’t just theoretical. Rachon et al. (2026) surveyed 90 draft NA samples from the US, Belgium, UK, and Spain. The good news is that no sample tested showed any presence of E. coli or Salmonella. The bad news is that, while 51% were classified as good quality (under 1,000 CFU/mL spoilage bacteria), 32% were classified as acceptable (1,000-10,000 CFU/mL) and 17% were classified as low quality (over 10,000 CFU/mL). And the low quality samples weren’t clustered at the threshold either. They ranged from just over 10,000 up to 2.4 million CFU/mL.

They then performed a separate challenge test, inoculating cans of NA beer with E. coli and Salmonella at various levels of CO2. Pathogens were inactivated at 2.8 v/v of CO2. At 1.2 v/v, growth began to appear, but only in samples with added sugar. Growth appeared across most variants at 0.8-1.0 v/v. Notably, this beer was selected based on earlier research (Rachon et al., 2024) showing pathogen growth at elevated pH (4.2–4.6) under reduced-carbonation, oxygen-exposed conditions. pH is functioning here as a fixed condition of the test rather than a variable this study measured directly.

It’s worth noting that the 2024 study, in its field survey, found two opportunistic pathogens, Cupriavidus gilardii and Sphingomonas paucimobilis, isolated specifically from keg beers during untargeted sequencing. They aren’t the usual suspects, but real organisms of concern nonetheless. C. gilardii is classified as a hazard group 2 organism.

The 2026 challenge test only tracked E. coli and Salmonella though, and says nothing about the spoilage organisms behind the 17% poor quality figure from the NA draft samples. So while CO2 does real work against pathogens, we don’t actually know yet if it does the same against spoilage bacteria.

We still can’t pasteurize kegs (would be fun if someone figured out a way to), and carbonation’s role against spoilage organisms is still unproven. Moderate hop bitterness has literature behind it as an additional hurdle against certain bacteria, though it isn’t a standalone fix. The remaining lever getting attention right now is additive-based solutions.

This itself is complicated. Many consumers distrust conventional preservatives like potassium sorbate and sodium benzoate, so much so that Whole Foods bans both outright, along with a long list of other synthetic preservatives. While effective, and still a real option for micro-stability, these ingredients are often eschewed based on consumer perception and preference.

There are some newer kids on the block currently disrupting the preservative paradigm. Chiber and Nagardo are two that come to mind. Chiber™ (Chinova Bioworks) is a chitosan (fiber/polysaccharide) derived from white button mushrooms, while Nagardo® (LANXESS, the same company behind Velcorin) is a glycolipid derived from the sweet osmanthus ear mushroom. Both are fungal-derived and target microbial cell membranes as their mechanism. Nagardo has general FDA approval for beverage use, but still needs TTB formula approval specifically for beer. Chiber is GRAS, including for use in beer.

Testing on these two products is thinner than the marketing suggests. Chiber has been through a challenge study in beer against pathogens, though not beer spoilage organisms. Maust et al. (2026) tested it alone at pH 5.0 with no carbonation, the least favorable conditions in the study, and results were mixed. It fared well against some pathogens (Listeria, B. cereus) but barely moved the needle against Salmonella. E. coli was left recoverable. 

Nagardo has had more testing, though not yet in beer. The published work (Galasong et al., 2025) tests it against spoilage yeasts, mold, and bacteria in iced tea, juice, and sparkling water, the microorganisms presumably responsible for the 17% low quality above, but not against any pathogens, and not in draft NA systems. And with largely inconclusive bacterial results, its effectiveness in draft NA systems remains to be seen.

Process and recipe considerations are all tools brewers can use to mitigate microbial spoilage in kegs, though without some method of pasteurizing kegs, it will remain incomplete. What’s outside the control of the brewer is what happens when the keg leaves the facility and makes its way to the tap and through draft lines. No formulation consideration can fix bad dispense hygiene.