Related Experiment Videos
Occurrence of Bacillus cereus in milk and milk products in Egypt
Abstract:
The presence of B. cereus spores in raw, pasteurized, and dry milk as well as in Damietta and processed cheese and in a baby food product was investigated, using three selective agar media for enumeration. The organism was detected in 70, 90, and 50% of milk, in processed and Damietta cheese samples, respectively. Spore counts varied from 10(2) to 10(6) and from 10 to 10(2)/ml of raw and pasteurized milk, respectively. In the two types of cheese and dried milk spore densities reached 10 to 10(3)/g. Egg yolk agar (E) gave better recovery rate of B. cereus when compared to the other two media, containing lithium chloride plus polymyxine B- sulphat (I) or polymyxin B-sulphate alone (KG). The latter agar medium favoured the development of larger colonies, surrounded by a more distinctive zone of precipitation.
Insights
Bacillus cereus spores are common contaminants in various dairy products and baby food. Egg yolk agar proved most effective for detecting these spores, crucial for food safety.
Area of Science:
- Food Microbiology
- Microbial Contamination
- Dairy Science
Background:
- Bacillus cereus is a foodborne pathogen that can form spores, posing a risk in dairy products.
- Spore contamination in milk, cheese, and baby food requires effective detection methods.
Purpose of the Study:
- To investigate the prevalence of Bacillus cereus spores in diverse dairy products and a baby food.
- To compare the efficacy of three selective agar media for B. cereus enumeration.
Main Methods:
- Samples of raw, pasteurized, and dry milk, Damietta cheese, processed cheese, and baby food were analyzed.
- Three selective agar media (Egg yolk agar, Lithium chloride plus polymyxine B-sulphate agar, Polymyxin B-sulphate agar) were used for enumeration.
- Spore counts and detection rates were determined for each product type.
Main Results:
- Bacillus cereus was detected in 70% of milk, 90% of processed cheese, and 50% of Damietta cheese samples.
- Spore counts ranged from 10^2 to 10^6/ml in raw milk and 10 to 10^2/ml in pasteurized milk.
- Egg yolk agar demonstrated a superior recovery rate for B. cereus compared to the other tested media.
Conclusions:
- Bacillus cereus spores are prevalent in the analyzed dairy products and baby food.
- Egg yolk agar is recommended for efficient detection and enumeration of B. cereus spores.
- Effective monitoring is essential for ensuring the safety of milk, cheese, and infant food products.