Prevalence and characterization of Bacillus cereus group from various marketed dairy products in India
Résumé
Bacillus cereus group, associated with foodborne outbreaks and dairy defects such as sweet curdling and bitterness of milk, is an indicator of poor hygiene, and high numbers are unacceptable. In the present study, the prevalence of B. cereus group was investigated in a total of 230 samples belonging to eight different types of dairy products marketed in India. The prevalence of B. cereus group in cheese, ice cream, milk powder, and milk was high (33%–55%), whereas it was low in butter and paneer samples (20% and 4%, respectively). None of the curd and khoa samples were found contaminated. The level of contamination in the various dairy products was up to 108 cfu.g−1 or mL−1. An antibiogram of 144 isolates of B. cereus group was obtained using 14 different antibiotics commonly used against foodborne diseases. All the 144 isolates were multidrug (at least five antibiotics) resistant. Ninety-three percent of them exhibited β-hemolysis. Of the 144 isolates, 97%, 96%, and 63% were capable of producing protease, lipase, and amylase, respectively, indicating spoilage potentiality of the isolates. Seventy-one percent of the isolates formed biofilm at 4 °C. The principal component analysis allowed classifying different correlated variables into two types of risks (spoilage and food poisoning). Hierarchical cluster analysis classified isolates into four main groups on the basis of the studied characters. The present study will help to better assess the health and spoilage risk associated with B. cereus group in dairy environment and to incorporate adequate preventive measures.
Origine : Publication financée par une institution
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