Year: 2023 | Month: October | Volume 13 | Issue 5
Selective Detection and Quantification of Viable Bacillus cereus by PMA qPCR from Ready-to-Eat Meat Products
S. Rathnapraba
B.J. Shathish Sharma
P. Kanagaraju and R. Narendrababu
DOI:10.30954/2277-940X.05.2023.5
Abstract:
Bacillus cereus is one of the common causative organisms causing major foodborne outbreaks. Quantitative polymerase chain (qPCR) reaction could detect Bacillus cereus contamination in food samples, but both the viable and dead bacteria are detected. However, only viable bacterial pathogens might seriously jeopardize the safety of food. Therefore, in this study we used Propidium monoazide (PMA) based qPCR to detect and quantify the viable food borne bacterial pathogen, Bacillus cereus in ready to eat meat products. As a reference strain, Bacillus cereus (ATCC 117783) was used for preparation of viable and dead cells from artificially spiked meat samples. DNA was extracted from PMA treated and untreated samples, subjected to PMA based qPCR and conventional qPCR using fem A gene specific primers designed in the study. Further, meat samples (n=50) were subjected to qPCR and PMA based qPCR for viable bacterial pathogen detection. Among the 50 samples screened, 16 samples were positive for PMA qPCR with a detection range of > 103 CFU/ml, whereas in conventional qPCR, 27 samples were positive. The more positivity in conventional qPCR is due to amplification of both live and dead bacteria from the meat products screened. In comparison to qPCR, less than half of the samples were amplified by PMA qPCR indicating detection of only viable bacteria in the samples screened, thus eliminating false positive results. Thus, culture independent PMA based qPCR may be useful for rapid and selective detection of Bacillus cereus that could aid in reliable risk assessment in ready to eat meat products.
Highlights
- Detection of viable food borne Bacillus cereus from ready to eat meat products using Propidium monoazide based qPCR targeting fem A gene.
- PMA treated qPCR samples resulted in 32% positivity, at a range of >103 CFU/ml that are unfit for consumption.
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