Molecular characterization of Bacillus cereus from milk and milk products
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Date
2018
Journal Title
Journal ISSN
Volume Title
Publisher
Indian Dairy Association
Abstract
Bacillus cereus is the major bacterial foodborne
pathogens that cause various foodborne outbreaks worldwide.
The occurrence of B. cereus in food environment is predominant
and it has been characterized as both spoilage as well as
pathogenic microorganism. In the present study, the incidence
of B. cereus was investigated in a total of one fifty samples
including raw milk, khoa, pasteurized milk and paneer collected
from different retail outlets in Chennai. The samples were screened
for the presence of Bacillus cereus by conventional culture
method on selective Mannitol egg yolk polymyxin (MYP) medium.
The colonies were confirmed by their colony morphology, Gram’s
staining and biochemical characterization. Microbial screening
revealed predominance of Bacillus cereus. Further, all the culture
positive colonies were subjected for PCR amplification by
targeting Haemolysin (HL) gene. B. cereus was detected in 51
samples with an overall prevalence of 34%. Antibiotic
susceptibility pattern revealed that the isolates were highly
resistant to penicillin G (100%) and 100% sensitive to gentamicin,
streptomycin, chloramphenicol, erythromycin and tetracycline.
PCR positive samples were bulk produced, purified and
sequenced and analyzed using DNA star sequence package. The
BLAST analysis results revealed that Bacillus cereus isolates
have 94% homology with the other Bacillus cereus isolates in
the NCBI database. Thus in the present study revealed that, a
relatively higher percent of the samples did not comply with the
standard quality. Hence, the hygienic quality of milk and milk
products needs to be improved considerably at different levels
of processing to ensure food safety to the consumers.
Description
TNV_IJDS_2018_71(6)637-640
Keywords
Veterinary Science