Source

Bacillus cereus is a lesser-known food poisoning culprit.  Naturally occurring in some types of soil, Bacillus cereus bacteria have been implicated in outbreaks associated with consuming raw fruits and vegetables or their unpasteurized products, as well as several other types of food.

The bacteria can cause two different kinds of illness – diarrheal and emetic, or vomiting-type – depending on what foods are contaminated and the toxins that develop as a result.  Diarrheal illnesses are most often associated with meats, milk, vegetables and fish.  Food poisoning that produces vomiting is commonly linked to starchy foods such as rice, potatoes, pasta and cheese.

Outbreaks associated with Bacillus cereus bacteria are frequently tied to foods composed of several different ingredients. Examples include sauces, puddings, soups, casseroles, pastries and salads.

It is believed all people are susceptible to food poisoning from Bacillus cereus.

Incubation

When an infection causing diarrheal-type illness occurs, symptoms begin to appear between six and 15 hours after infection.  If the illness is caused by the toxin that produces vomiting, symptoms can appear anywhere from 30 minutes to  hours after consumption.

Symptoms

Diarrheal-type illness produces symptoms such as watery diarrhea, abdominal cramps and occasionally nausea. Vomiting rarely accompanies this type. 

Emetic illness is primarily associated with nausea and vomiting.  Abdominal cramping and diarrhea have also been known to occur. 

Duration

For both illnesses caused by Bacillus cereus, symptoms usually subside within 24 hours of onset.  

In severe food poisoning cases, long-term complications from bacterial infection may occur, such as gangrene and septic meningitis.  Death may occur in infants because of their underdeveloped immune system.  No complications specific to Bacillus cereus poisoning have been identified, however.

Action

Diagnosing Bacillus cereus food poisoning can be difficult because it produces symptoms similar to other common bacterial illnesses, such as Staphylococcus aureus and Clostridium perfringens.  Only a doctor can determine whether an illness is caused by Bacillus cereus.  Fecal samples can be used to identify the infection, and samples from suspected foods can be used as further confirmation of the type of illness.

During the course of the infection, it is best to drink plenty of fluids and get rest.  Seek medical attention if symptoms become severe or last longer than 24 hours.

Prevention

Preventing food poisoning caused by Bacillus cereus can be difficult, particularly because the toxins produced by the bacteria are highly heat-resistant.  However, the bacteria that produce the toxins multiply the fastest at temperatures between 86 and 122 degrees Fahrenheit; they may even be able to spread at temperatures as low as 40 F. 

To prevent the spread of bacteria, always keep food out of the “Danger Zone,” between 40 and 140 F. 

Sources:

Iowa State University. "Bacillus cereus," http://www.extension.iastate.edu/foodsafety/pathogens/index.cfm?parent=37&articleID=166; accessed 8 Dec. 2009.

Food and Drug Administration. "Bacillus cereus," http://www.fda.gov/Food/FoodSafety/FoodborneIllness/FoodborneIllnessFoodbornePathogensNaturalToxins/BadBugBook/ucm070492.htm; accessed 8 Dec. 2009.

Safefood.net.au. "Bacillus cereus and other Bacillus species," http://www.safefood.net.au/AudienceHierarchy/TheBugBible/Bacillus+cereus+and+other+Bacillus+species.htm; accessed 8 Dec. 2009.

New Zealand Food Safety Authority. "Bacillus cereus," http://www.nzfsa.govt.nz/science/data-sheets/bacillus-cereus.pdf; accessed 8 Dec. 2009.

Image Source:

Inra.fr. http://www.inra.fr/var/mica/storage/htmlarea/3232/dorner_spore.jpg; accessed 8 Dec. 2009.