How Could Lucky Charms and Cheerios Cause Food Poisoning?

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Transcript:
Dry breakfast cereal is allegedly making people (thousands of people!) sick in the USA, as I mentioned last week.

This week, I put on my food scientist hat to dive into the possible causes.
In an attempt to keep this brief, what follows is a not-at-all in-depth discussion of six possible causes.

One. There is no causal link between the cereals and the illnesses

The illnesses could be caused by something other than the cereal, but since so many people eat these cereals they are blaming the cereal.

For example, one person who posted on an online illness reporting site didn’t decide that her illness was caused by breakfast cereal until she heard about other people getting sick: “Reporting nausea and vomiting from a double pack of Honey Nut Cheerios …. I’m currently pregnant so I thought nothing of it at first but it traces back to the [last] few times I had this cereal”

Two. There is a microbiological problem with the cereal

Viable cells of bacteria or fungus could be present in the cereal pieces, although this is unlikely. Lucky Charms and Cheerios are both made using a process called extrusion, followed by drying or baking. Extrusion and baking will reliably kill all vegetative bacterial cells, moulds and viruses, although not necessarily spores of bacteria or mould.

For live bacteria or mould pathogens to be present at infective numbers – levels enough to make you sick – the manufacturer would have had to hold the extruded (damp) cereal for more than four hours before baking it. Even then, you would need to start with severely contaminated material for enough growth to occur.

Post-baking contamination is possible, but this would require pretty severe mishandling to result in infective doses of bacteria - such as Salmonella - on the cereal. Contamination with a food-borne virus is more likely.

The food-borne virus norovirus is one of the most infective agents known to man and just a few viral particles can cause illness. For example, in 2011, a single source of contamination – possibly one infected food handler - caused 11,000 norovirus illnesses in Europe. Enteric viruses can survive on low moisture foods, including cornflakes, for at least four weeks.

So, norovirus contamination is possible, noting that the contamination would have to occur after baking. It’s also worth noting that it is extremely difficult to isolate viral particles from foods. This means it would be very difficult to find “the smoking gun” if a food-borne virus like norovirus was the cause.

Three. There are microbiological problems with the marshmallow pieces

Lucky Charms contain small marshmallow pieces. The marshmallows could have a microbiological problem. However, this theory does not explain the links between the illnesses and Cheerios, which do not contain marshmallow pieces.

Four. There are natural toxins in the products

Natural toxins are produced by microorganisms such as bacteria, moulds and algae. In a cereal product, the most likely class of natural toxin is a mycotoxin, because these can occur in grains like oats and corn. Both of the affected cereals, Lucky Charms and Cheerios, contain oats, making mycotoxin a good candidate.

A bacterial toxin is less likely to be present than a mycotoxin, although the heat-stable Staphylococcus aureus toxin might be able to survive the baking process. This toxin causes nausea, vomiting and stomach cramps within a few hours of eating contaminated food, which matches some of the victims’ symptoms. For it to be present in the cereal, the unbaked product would need to have been wet enough for the bacteria to grow and make the toxin. This seems unlikely because grains are usually fed into an extruder in a dry(ish) format.

Five. There are man-made chemical toxins in the product(s), by accident

Lucky Charms contain four artificial colours, including two that have been linked to health problems by some groups. An accidental overuse of one of those colours might have caused problems for some consumers.

Some food safety specialists have speculated that a change of source for one of the colours, or even a fraud problem with one of the colours could cause a chemical contamination event.
Interestingly, the maker of both products, General Mills, said in March that it was having problems acquiring ingredients and that it had to find new sources of some ingredients.

“We’ve adjusted formulations,” said John Nudi, the company’s president of North America retail. “In some of our products, we’ve reformulated over 20 times year to date. Every time you make an ingredient change, you have to change the formulation.” (as quoted in the New York Post)

Fraudulent food ..........