FAO Warns Toxic Gut Bacteria Are Still Slipping Past Food Safety Rules

If you have ever wondered how a sealed container of infant formula or a properly cooked buffet tray could still make someone seriously ill, the answer often traces back to a family of gut bacteria that food safety systems were not built to catch. A joint expert panel convened by the Food and Agriculture Organization (FAO) and World Health Organization (WHO) just finished the most thorough review in years of toxin-producing Clostridia, the bacterial family behind botulism, a common form of food poisoning, and one of the toughest hospital-acquired gut infections around. The timing is not an accident: the review lands months after a real infant formula botulism outbreak sickened dozens of babies in the United States, and its conclusions push directly against a gut mechanism, spore survival in the digestive tract, that current food safety rules were not designed around.

Key takeaways

• A joint FAO/WHO expert panel reviewed the global evidence on three toxin-producing Clostridia species and concluded current food safety controls are not fully catching them.
• The panel put a number on the human cost: botulism alone carries an estimated $1.68 million cost per case, and Clostridioides difficile (C. diff) costs an estimated $5.9 billion a year in the US alone.
• The report is tied to a real 2025 to 2026 outbreak in which Clostridium botulinum spores in an infant formula ingredient sickened 48 infants across 17 states, because the bacteria colonized their immature gut.
• The panel is recommending an update to global food safety standards (Codex Alimentarius) to treat these toxin-producing bacteria as a higher priority, though the review itself does not establish that any single new detection or control method is ready for widespread use.

Toxin-producing Clostridia are outpacing current food safety controls, FAO/WHO panel finds

The core finding is that toxigenic (toxin-producing) Clostridia, a group of spore-forming gut bacteria, remain a significant and likely underestimated food safety threat despite decades of regulation aimed at other pathogens. The panel, convened by FAO's food safety program at an expert meeting in Rome in February 2025, focused on three species: Clostridium botulinum (which produces botulinum neurotoxin, or BoNT), Clostridium perfringens, and Clostridioides difficile. What sets this group apart from more familiar foodborne culprits like Salmonella or Listeria is that they form spores, dormant, armor-plated versions of the bacterial cell that can survive cooking, pasteurization, and many standard sanitizers. That survival trait is the throughline of the entire report: it is the reason these bacteria keep resurfacing in food supplies that have otherwise been engineered to be safe.

Infant formula, hospital wards and buffet lines are where the real-world stakes show up

The report's timing lines up with a concrete case: an outbreak linked to a US infant formula brand in which C. botulinum spores were found in a powdered whole milk ingredient. According to CDC's outbreak investigation, by late February 2026 the case count had reached 48 infants across 17 states, and FDA's recall notice confirms the manufacturer pulled all batches of the affected formula nationwide in November 2025. This is where the gut-microbiome angle matters most: infant botulism does not require pre-formed toxin in the food itself. Instead, the spores are swallowed, survive the trip through the stomach, and then germinate and colonize the infant's gut, because a baby's microbiome has not yet matured enough to competitively exclude the invader. Genetic sequencing tied the strains found in the raw milk powder ingredient, the finished formula, and a sick infant's own clinical sample together, according to Food Safety Magazine's coverage of the investigation. Beyond infants, the report also flags C. perfringens as one of the most common causes of bacterial foodborne illness generally, and C. difficile as a driver of antibiotic-associated diarrhea and colitis, a condition that disproportionately affects hospitalized and older adults whose gut bacteria have already been disrupted by antibiotics.

The panel built its case from decades of outbreak and burden data, not a single new experiment

Because this is an expert-body synthesis rather than a single lab study, its credibility rests on breadth rather than a novel experiment. The FAO/WHO Joint Expert Meetings on Microbiological Risk Assessment (JEMRA) panel systematically reviewed peer-reviewed literature, outbreak surveillance records, and existing disease-burden estimates across all three pathogens to produce comparable figures. Those figures are the report's most quotable output: botulism carries an estimated burden of 1,036 disability-adjusted life years (DALYs, a standard measure combining years lost to death and years lived with illness) and an average cost of $1.68 million per case; C. perfringens causes an estimated 6,963 DALYs across European and other low-mortality countries and an estimated $342.7 million in annual economic burden in the United States; and C. difficile costs an estimated €3.4 billion a year in Europe and $5.9 billion a year in the US. The panel also quantified just how little BoNT it takes to cause harm: as little as 50 nanograms, a fraction of the weight of a grain of salt, can trigger severe or fatal poisoning.

What this means if you are trying to protect yourself or a family member

None of this points to a new supplement, test, or diet to add to your routine. The practical takeaway is closer to basic food-safety hygiene, applied with extra caution around the specific risk factors the report highlights. Powdered infant formula is not sterile, so the report's findings reinforce existing guidance from pediatric and public health bodies to prepare it carefully and store it properly, and to take any recall notice for formula seriously rather than assuming an open container already in use is unaffected. For anyone prescribed antibiotics, especially older adults or those with recent hospital stays, it is worth asking a doctor about the risk of C. difficile overgrowth, since that infection specifically exploits a gut microbiome that antibiotics have already thinned out. And for home cooking, the report's emphasis on spore survival is a reminder that "cooked" is not the same as "sterile": foods held at unsafe warm temperatures after cooking, a classic setup for C. perfringens growth, remain a real risk even when the food looked and smelled fine.

The report is explicit about what it does not settle

The panel is upfront that this is a synthesis of existing evidence, not new experimental research, and its authors note that detection methods for these bacteria in food, particularly rapid, field-usable tests, still lag behind what is available for other major foodborne pathogens. The report is also food-safety and toxin focused rather than a direct study of gut mechanisms, so while the infant botulism case illustrates how these bacteria interact with an immature microbiome, the review itself does not test or resolve broader questions about how a mature adult gut microbiome resists or fails to resist colonization by these species.

Global food safety standards could shift within the next few years

The most concrete next step named in the report is a recommendation to Codex Alimentarius, the joint FAO/WHO body that sets international food safety standards, to formally elevate BoNT-producing Clostridia to a priority hazard category. That recommendation was put before the relevant Codex committee in mid-2026, but formal adoption of new global standards typically takes multiple committee cycles, so any resulting changes to labeling, testing requirements, or import rules are unlikely to appear immediately.

Common questions

Is my sealed, unopened infant formula at risk? The report does not suggest all formula is unsafe; the documented outbreak was tied to a specific ingredient lot from one brand, which was recalled. The practical step is checking any formula you have against active FDA and CDC recall notices rather than assuming risk applies broadly.

Why does this affect babies more than adults? Infant botulism specifically depends on an immature gut microbiome that has not yet developed the competitive bacterial community needed to block spore germination and colonization, a defense that develops with age.

Is C. diff the same thing as regular food poisoning? No. C. difficile colitis is most strongly linked to antibiotic use disrupting the gut microbiome, not to a single contaminated meal, though the report treats it as part of the same foodborne-transmission picture.

Does cooking food kill these bacteria? Not reliably. The spore form of these bacteria can survive normal cooking and pasteurization temperatures, which is precisely why the report frames them as a persistent, hard-to-eliminate risk rather than one solved by heat alone.

References

1. (2026). Toxigenic Clostridia in foodborne disease: characterization, exposure, burden, control and detection. https://doi.org/10.4060/cd9619en
2. CDC Investigation Update: Infant Botulism Outbreak, November 2025. cdc.gov. https://www.cdc.gov/botulism/outbreaks-investigations/infant-formula-nov-2025/investigation.html
3. FDA: ByHeart Voluntary Recall Notice. fda.gov. https://www.fda.gov/safety/recalls-market-withdrawals-safety-alerts/byheart-updates-information-regarding-voluntary-recall-all-batches-byheart-whole-nutrition-infant