TraditionalREF 610114
Organism · Solutions
Bacillus cereus testing
Bacillus cereus survives cooking as a spore and germinates as food cools — which is why it is primarily a temperature-abuse organism, and why rice, pasta and dairy products carry the highest risk.
Pink colonies with precipitate · MYP agar
Why Bacillus cereus testing is demanding
B. cereus forms heat-resistant spores that routinely survive cooking. The organism itself is easily killed; the spores are not, and they germinate as a cooked product cools through the temperature range where growth is possible. This makes it fundamentally a cooling-and-holding problem rather than a cooking one.
It produces two distinct toxin types — an emetic toxin that is heat-stable and a diarrhoeal toxin that is not — which means reheating a temperature-abused product may destroy the organism and one toxin while leaving the other intact. Starchy foods held warm are the classic vehicle.
Enumeration on mannitol egg yolk polymyxin agar gives characteristic colonies with a precipitate zone. The count is interpreted against a threshold rather than as absence, because low levels of B. cereus are common and unremarkable in many raw materials.
- Role
- Temperature-abuse hazard
- Result type
- Enumeration
- Reference method
- ISO 7932
- Result
- 24–48 h
Methods compared
Enumerated against a threshold — the routes to a defensible count.
- Traditional · ISO 7932MYP enumeration
Colony-count technique on mannitol egg yolk polymyxin agar, reading characteristic pink colonies with a precipitation zone.
Time to result24–48 h - RapidChromogenic formats
Chromogenic media that improve differentiation of presumptive B. cereus from background Bacillus flora at the reading stage.
Time to result24 h - Molecular · PCRToxin gene profiling
PCR distinguishing emetic from diarrhoeal toxin gene profiles, where an incident investigation needs to establish which toxin type is implicated.
Time to resultSame day
Low counts are normal in raw materials — interpret against the specified threshold.
Ask usProducts for Bacillus cereus testing
A selection spanning culture media, rapid formats and molecular assays. The full range is in the catalogue.
Standards & compliance
The references a B. cereus programme is measured against.
- ISO 7932
- Horizontal method for the enumeration of presumptive Bacillus cereus — colony-count technique at 30 °C.
- ISO 21871
- Determination of low numbers of presumptive B. cereus by MPN and detection, for products where counts are expected to be low.
- SFDA
- Supplied through an SFDA-licensed establishment, aligned to Kingdom requirements for the matrices you test.
- ISO/IEC 17025
- Suitable for accredited laboratories, with lot documentation and traceability available on request.
Sourced from the brands your methods are built on.
Testing for Bacillus cereus?
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