- Print Friendly - Help

Dried Potato Flakes and Food Safety

Why are dried potato flakes a food safety concern?

Dried potato flakes commonly contain a toxin-producing bacteria called Bacillus Cereus.
B. cereus is widely distributed in the environment and occurs naturally in most foods.

The bacteria can survive the drying process by producing resistant spores. Once the potato flakes are re-hydrated, these spores can germinate and multiply and produce a toxin which can cause nausea, vomiting and diarrhoea. Illness usually occurs 1-6 hours after eating contaminated food.

Is this toxin always produced if B. cereus is present in the food?

No. The bacteria B. cereus is often present in foods of vegetable origin and its presence in low numbers is not a food safety concern.

The toxin can be produced however if the re-hydrated potato is stored at temperatures between 10 and 60 degrees Celsius for a couple of hours, as levels of the toxin high enough to cause foodborne illness can be produced in this time.

Reheating the potato after the toxin has been produced and is present in the food does not destroy the toxin and the food will still be unsafe to eat. The toxin can withstand heating for 90 minutes at a temperature of 126 degrees Celsius.

What can go wrong?

The chances of the B. cereus toxin forming in reconstituted potato flakes increase if the rehydrated product is stored at an incorrect temperature for a couple of hours, or long enough to allow the B. cereus spores to germinate and grow in number to high enough levels to produce large amounts of the toxin. If the product is stored either alone or as part of another product (for example potato-topped pie) at between 10 and 60 degrees Celsius for this length of time the bacteria will grow to levels considered hazardous to human health.

What can I do to avoid potato flakes becoming a source of foodborne illness?

To avoid foodborne illness caused by the B. cereus toxin, you should make sure that the product, once re-hydrated, is either kept hot at above 60 degrees Celsius, or cooled and stored under refrigeration until used.