- Do not leave cooked food unrefrigerated for several hours
- If possible, set the refrigerator below 5 °C; place larger quantities of food in the refrigerator, divided into two containers.
- Always prepare baby food fresh, do not keep it warm for more than one hour (e.g. in thermos containers or in a bottle warmer), throw away leftovers
Bacillus cereus bacteria are found everywhere in the soil, in dust, on plants or on animal hair. To some extent, they are particularly resistant to heating and can therefore survive common cooking temperatures that kill almost all other bacteria. Particularly in cooked and reheated side dishes such as rice and noodle dishes, Bacillus cereus bacteria can multiply under certain circumstances and lead on the one hand to nausea, vomiting, but also to diarrhea.
The resistant bacteria are present in the dry raw materials, but cannot multiply because of the low water content. The particularly resistant forms survive cooking without any problems. In the finished dishes, as soon as the food has cooled down somewhat, they can then multiply strongly in a few hours and possibly also produce toxins. This happens mainly when the food is left unrefrigerated in the kitchen or on the balcony. But even in the refrigerator, multiplication is prevented only if the temperature is set below 5 °C if possible (this temperature is also optimal for other foods) and if too large quantities do not have to be cooled at once. In the case of large quantities of rice or pasta, it takes a very long time for even the inner layers to cool sufficiently to prevent multiplication.
Nausea and vomiting can be caused by toxins (poisonous substances). These are formed in sufficient quantities when special Bacillus cereus bacteria(toxin-forming bacteria) have been able to multiply strongly and thus produce sufficient quantities of toxins in the food. Since in this case the finished toxins are ingested, vomiting and nausea occur after a short time. The symptoms usually improve within a day. The bacteria themselves can cause diarrhea if they are allowed to proliferate in food during prolonged, inadequately refrigerated storage. Diarrhea then occurs about sixteen hours after consumption of the food due to the effects of the bacteria directly in the intestine.
The proportion of reported foodborne illnesses caused by Bacillus cereus ranges from 0.3% to 18% in Europe. A long-term study in the USA from 1973 to 1987 showed 2 %, studies in Japan, Taiwan (high rice consumption) about 30 %. It should be noted that only reported illnesses are recorded in each case. Since nausea and vomiting occur very quickly after a meal, usually resolve within one to two days without serious consequences, and detection is relatively difficult, only a small proportion of these illnesses are reported and recorded.
Diarrheal diseases caused by Bacillus cereus are even more difficult to detect and for this reason are hardly recorded. It is therefore reasonable to assume that illnesses caused by Bacillus cereus are much more common than would be expected based on statistics. Foodborne illness outbreaks with larger numbers of ill persons have also been linked to Bacillus cere us in both Europe and the United States.