We take our responsibility to ByHeart families incredibly seriously and our intention is to use what we learn to evolve our testing protocols and manufacturing process to ensure that an outbreak like this does not happen again. To help make sense of and learn from the recent Clostridium botulinum outbreak connected to ByHeart formula, we sat down with Dr. Mansour Samadpour and Dr. Donald Zink from IEH Laboratories & Consulting Group to break down what is known about C. botulinum and its risks to dairy-based infant formula. 

Question: Dr. Zink, can you explain to us what Clostridium botulinum is and how it can enter the food and infant formula supply? 

Dr. Zink: Clostridium botulinum is a type of bacteria that lives naturally in the environment and soil and can be found in a wide variety of foods including root vegetables, fishery products, dairy products, grains, spices, meat products and even honey. Clostridium botulinum exists as spores that are not only widespread in the environment, but can also survive harsh conditions like heat, drying and pasteurization, often appearing in milk and processing facilities at low levels. 

Under conditions of very little or no oxygen [exclusively this? what else?], these spores grow and produce potent neurotoxins called botulinum toxins. While harmless to healthy adults, these toxins pose a serious risk to infants due to their immature gastrointestinal tract and gut microbiomes. Exposure typically comes from ingesting spores found in the environment via dust or dirt, or from food products in which the neurotoxins are able to form. When an infant consumes the spores of Clostridium botulinum, these spores get into the intestinal tract and they germinate, grow, and colonize the intestinal tract. There, they start producing toxins, and those toxins are absorbed into the bloodstream, leading to a rare but serious illness that can affect the infant’s nervous system. 

What are the signs and symptoms of infant botulism? 

Dr. Zink: The botulinum toxin interferes with nerve signaling to muscles. In infants, this can lead to infant botulism, which may cause symptoms like poor feeding, weakness, a weak cry, constipation, and breathing difficulties. Infant botulism is rare, but because infants’ digestive systems are still developing, they are more vulnerable than adults.

In the U.S, there are hundreds of cases a year of infant botulism, with the vast majority of infant botulism cases reported as caused by the child consuming dust or dirt from the home. The recent outbreak from ByHeart infant formula was the first of its kind and scale. [citations needed]

Approximately 88% of annual cases are in infants under six months of age, and the remaining 12% are in infants over six months. It’s very rare in children older than one, but children or adults who are immunocompromised or have imbalanced microbiomes are more susceptible. [citations needed]

“The challenge is that specific testing for C. botulinum is not currently an industry standard for infant formula or dairy ingredients.” 

Why is Infant Formula Especially Vulnerable? 

Dr. Samadpour: This is the first large-scale outbreak tied to infant formula in the last [XX YEARS], challenging long-held assumptions about risk and testing protocols in the dairy-based infant formula supply chain.

While the industry has purported for decades that C. botulinum is not an issue to worry about, this recent outbreak shows the very real hazard it poses. The challenge is that specific testing for C. botulinum is not currently an industry standard for infant formula or dairy ingredients. Instead, the industry and regulators rely on preventive controls and indicator tests to ensure stricter supplier selection and qualification, and to manage microbiological risk. 

What’s most notable, though, and what our analysis has found, is that traditional “indicator” organisms, such as sulfite-reducing clostridia (SRC), are not reliable proxies for the presence or absence of C. botulinum and that SRC testing was insufficient. In our use of SRC, all [XX??] were below detection level. Our data clearly shows that SRC alone would not have been successful in preventing this outbreak caused by C. botulinum spores.  

We now know for certain that the existing safeguards are insufficient. This outbreak revealed that this pathogen can and has made its way into the infant formula supply chain.

In addition, it is extremely difficult to isolate the organism. [In one case, it took 1,300 colonies to find the PCR positive. Most labs stop at 5-10 colonies. I can’t stress enough that companies should not stop at a PCR result if you’ve only taken 5-10 colonies. Hundreds are needed, at least. In our testing, C. botulinum started showing up after 24 cycles, which means 1 out of 10,000 colonies is C. botulinum.] [Need more info and clarification] 

How is infant formula currently tested for C. botulinum? 

[IEH to add insight into current testing methods and practices and limitations] 

Current infant formula testing for C. botulinum relies primarily on detection of sulfite-reducing clostridia (SRC), a category of organisms used to indicate the potential presence of C. botulinum. It is not a direct test for C. botulinum itself.

C. botulinum is difficult to test for directly at scale, so the industry has historically used SRC as a proxy. If sulfite-reducing clostridia are absent, the assumption is that C. botulinum is unlikely to be present. The problem is that this assumption has limits. A negative SRC result doesn't guarantee C. botulinum is absent, just that it wasn’t detected.

For most foods, this approach carries acceptable risk. For powdered infant formula, however, the margin for assumption is considerably narrower. The question our research with ByHeart set out to answer is whether the industry's reliance on SRC as a proxy is sufficient for this specific product.

It was determined a more direct detection methodology was needed – one designed specifically for the biology of powdered formula. 

How do we prevent C. botulinum from getting into infant formula? 

Dr. Samadpour: Managing the risk of C.botulinum is about prevention and control rather than elimination. The risk of botulism from foods is focused on preventing the spores from germinating, growing and producing the toxin in foods. This involves control of pH, water activity, storage temperature or thermal processes that destroy the spores.

We worked with ByHeart to develop and institute new testing protocols, and will be testing for C. botulinum on every batch of the finished infant formula and at various key touchpoints throughout the supply chain. What is needed is a comprehensive set of additional preventative controls throughout the supply chain and manufacturing process to safeguard risk posed by C.botulinium or other spore-forming bacteria. 

Though C. botulinum has been studied for over a hundred years, there is still so much we do not know. We have a task force dedicated to developing a comprehensive set of additional preventive controls and testing for C. botulinum throughout the infant formula supply chain and on finished formula, in addition to seeking to identify future risks and opportunities to strengthen protections against spore-forming bacteria.

Thank you, Dr. Zink and Dr. Samadpour for sharing your insights and knowledge. To learn more about the new C.botulinum testing protocol ByHeart developed with IEH, or to read the research paper published in Frontiers that delves deeper into the limitations of SRC testing, see below.