Within the last year, two brands of formula — ByHeart and Nara Organics — have recalled all of their products due to outbreaks of infant botulism. This has, understandably, left parents confused and afraid. Fortunately, no babies have died, but some have become seriously ill.

I've written about what parents can do immediately, including symptoms of infant botulism and what to do if your child was exposed to these formulas. But I know there are a lot of broader questions about what this means for anyone using formula. Parents are asking some version of WTF is going on here? And, more importantly, how do we know our formula is safe?

Today: a review of what's happened, along with new information on what we know about the outbreaks, whether they are possibly linked, and what that means for next steps for parents.

What happened?

In October 2025, the FDA, CDC, and California Department of Public Health identified a multistate outbreak of botulism in infants. Infant botulism is caused by infants consuming food contaminated with Clostridium botulinum. These bacteria produce spores that can make infants sick, due to their less-developed gut. (Adults and older children are not at risk, even though we likely do consume foods with these bacteria.)

It is often hard to identify the cause of an outbreak like this. The bacteria are found widely in the environment, and there are many sources that could be responsible for a single illness. In addition, because botulism takes up to 30 days to develop in infants, it can be difficult to draw links between cases. In this particular case, however, the affected infants were linked through their consumption of ByHeart Whole Nutrition Infant Formula.

At the time, ByHeart made up less than 1% of formula sales in the U.S., which made tracking it somewhat easier. Ultimately, evidence of botulism was found in unopened cans of formula, making it clear this was the cause, and all ByHeart formula was recalled.

This outbreak was the first time that infant formula had been recalled due to botulism anywhere in the world. However, recalls for other reasons are not unheard of. In 2022, you may remember the nationwide formula shortage as a result of the Abbott/Similac shutdown. This is because a different type of bacteria (Cronobacter) was found in the formula and may have been linked to several illnesses and deaths.

A very unfortunate twist here is that when ByHeart recalled its formula, they offered their users a 20% discount on Nara Organics formula — another whole-milk organic option. Then, in June 2026, three new cases of infant botulism were identified and connected to Nara Organics formula. Nara Organics also issued a full recall of all products. As of right now, the CDC and FDA have not identified any additional cases, which is reassuring given the time that has passed since the first cases.

At this stage, both outbreaks are still under investigation by the FDA.

Are the two outbreaks connected?

It is natural to ask whether the outbreaks are connected — and I think this is the question on everyone's mind, especially given that these are two small brands making organic whole-milk formula options.

We have new data that suggests the answer to this may well be yes. In particular, there may be a link through a shared supplier of the powdered milk they used.

More specifically, the FDA's preliminary findings on the ByHeart outbreak point to contamination in its raw ingredients — specifically, they found botulism bacteria in a sample of the powdered whole milk it used. Although this is an ongoing investigation, it's strongly believed that it is the source of their outbreak.

The provider of ByHeart's powdered milk is a company called Organic West Milk, and the milk was spray-dried at a facility operated by Dairy Farmers of America.

Nara Organics formula is currently made from powdered milk sourced in the EU, where its manufacturing facilities are. However, from October 2024 through April 2025, while looking for an EU-based supplier, Nara also sourced whole milk powder from Organic West Milk, and it was spray-dried by Dairy Farms of America at the same plant that ByHeart used. Some of the formula made from this milk was still on the shelves more recently, and may be the source of the new outbreak. As of now, no additional formula brands have been identified as using this supplier.

(Nara was not aware of this connection across milk suppliers until early 2026, and at the time undertook extensive screening of their products for safety, using a procedure called SRC testing. Unfortunately, new data released in June of 2026 suggests that testing isn't sufficient to detect very low levels of this bacteria.)

We should know more in the next several weeks. It remains possible that these are unrelated, but that seems increasingly unlikely with this new information.

Regardless of the connection, one thing this has revealed is that lowering the risk of botulism in infant formula may require testing beyond what is currently being done. This requires regulatory oversight. Currently, companies are required to test for two other bacteria (Salmonella and Cronobacter), which can be detected more easily with standard lab equipment. Consistent testing for the bacteria that cause botulism would require more specialized laboratories than we have.

This is really an issue for the FDA. The scientific review they started last year, called " Operation Stork Speed", focuses primarily on infant formula nutrients, not outbreaks like these. I hope they take it up.

What should I do now?

I know this has left parents reeling. A lot of parents gravitated towards these brands because of a feeling that these were better options, and I understand the fear of switching — especially for parents who moved from ByHeart to Nara.

Here is what I would like to say: despite the marketing you'll hear, there is little to no evidence that any one formula brand is better than another for infant development. Any plausible effects would be absolutely tiny — far too small to really care about. The macro and micro nutrient profile of formulas is highly regulated, so your baby is getting almost exactly the same calorie mix and vitamins and minerals, regardless of what you use.

This doesn't mean that your baby won't like the taste of one formula better than others, and you may value organic formula for the same reasons some people prefer organic broccoli. You may feel better supporting a small brand. There is plenty of room for preferences here, as there are in all consumer goods. But from an evidence standpoint, there is no reason to expect that the formula you choose will have a meaningful long-term impact on your child. (If you need a specialized formula for some medical reason, that's a different story.)

None of this tells you what to do now, but it does tell you there are many good options, and you can feel good about switching to a different brand if needed.

The bottom line

Two formula recalls due to infant botulism are scary, and it seems highly likely there is a link between them: the provider of the powdered milk. However, this has yet to be confirmed.
If you need to switch formulas, you can do so with confidence. Despite what marketing suggests, there is no meaningful evidence that one brand of formula produces better outcomes than another. Your baby will be fine on a different formula.

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