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11.11.2024 - Foods

Bacillus cereus as a Cause of Foodborne Intoxications (2)

Due to a recent death case, where the cause is currently suspected to be a Bacillus cereus intoxication, we would like to provide you with important information about this bacterial toxin producer below. 

General Information:

Bacillus cereus is a rod-shaped, gram-positive bacterium that is widespread in the environment and often associated with food poisoning (vomiting and/or diarrhea). It is known for forming heat-resistant spores. These are heat stable and can partially survive heating steps in the manufacturing process. 

To properly assess the dangers posed by Bacillus cereus, it must be considered that these bacteria are capable of producing two distinct toxins. These are the emetic and diarrheal toxin. The two toxins differ both in their mode of action and in the symptoms they cause.

Emetic Toxin (Cereulide):

The emetic toxin, also known as cereulide, shows high resistance to heat. Symptoms mainly include nausea and vomiting, which typically occur within a period of 1 to 5 hours after consuming contaminated food. The toxin is particularly observed in starchy foods like rice, pasta, or potatoes. Cereulide is resistant to high temperatures, gastrointestinal enzymes, and the acidic pH value of the stomach. The latter explains the rapid and immediate symptoms after consumption. 

Diarrheal Toxin (Enterotoxins):

These are heat-labile toxins, released by the bacterium in the intestine. Symptoms include diarrhea, abdominal cramps, and in some cases, nausea. They appear within a period of 8 to 16 hours after consuming contaminated food. This form is often observed in association with protein-rich foods such as meat, dairy products, or sauces. The enterotoxins have low sensitivity to heat but exert their effects in the intestine, where they lead to fluid retention and thus cause diarrhea. 

The main differences between the two toxins lie in their heat stability, the site of toxin formation, and the symptoms they cause. The emetic toxin is formed in the food, is heat-stable, and leads to vomiting, while the diarrheal toxin is released in the intestine, is heat-labile, and causes delayed diarrhea. 

Testing for Bacillus cereus:

We offer fast and reliable testing for presumptive Bacillus cereus. In addition to ISO procedures, we also regularly apply an accredited rapid method in our laboratory. This only takes 1 day, compared to the testing duration of 2-3 days when using ISO methods.

Through advanced molecular biological methods, we can also differentiate between various species within the Bacillus cereus group.

In general, we offer the following rapid methods in our laboratory: 

Parameter                         Testing Duration                          Testing Principle                            Accreditation

Salmonella                                 1 Day                                                       RT-PCR                                                  Yes

TentaSpeed

Listeria monocytogenes/           6 Hours                                                 RT-PCR                                                  No

Listeria spp. 

Listeria monocytogenes/              1 Day                                                        RT-PCR                                                   Yes

Listeria spp.

Cronobacter spp.                          1 Day                                                        RT-PCR                                                  Yes

STEC/ VTEC                                 1 Day                                                        RT-PCR                                                  Yes

Campylobacter spp.                      2 Days                                                      Cultural                                                  Yes

Presumptive Bacillus cereus            1 Day                                                        Cultural                                                  Yes

Yeasts and molds              3 Days                                                     Cultural                                                  Yes

Lactic acid bacteria                       2 Days                                                       Cultural                                                  Yes

Pseudomonads                           2 Days                                                       Cultural                                                  Yes

Coagulase-positive

Staphylococci                              1 Day                                                        Cultural                                                 Yes

Legionella                                   6 Hours                                                  RT-PCR                                                No

Identification / 

Strain Comparison                            2 to 24 Hours                                        Maldi-Tof                                                Yes

Consult our experts on topics related to Bacillus cereus. We provide you with competent advice and deliver fast and reliable results. 

For further inquiries, our customer advisors or Dirk Lorenz are available by phone at 0781/96947-23 or via email at dirk.lorenz@bav-institut.de.