Multiplex Real-Time Polymerase Chain Reaction for Simultaneous Quantification of Salmonella spp., Escherichia coli, and Staphylococcus aureus in Different Food Matrices: Advantages and Disadvantages
Table 4
Advantages, disadvantages, and purposes of use of multiplex qPCR described in this study, ready-to-use Compact Dry, and traditional culture methodology in food industries.
Multiplex qPCR
Ready-to-use Compact Dry
Traditional culture
Bacterial amount inoculated
5.3 log10
5.3 log10
5.3 log10
Bacterial amount detected (average)
5.7 log10
6.6 log10
5.5 log10
Estimated time of analysis
2 hours (simultaneous quantification of Salmonella, E. coli and S. aureus )
1 day (E. coli and S. aureus) 2 days (Salmonella)
3-4 days ( S. aureus) 5-6 days ( E. coli) 5 days (Salmonella)
Advantages
(i) Monitoring in real time; (ii) Does not need to perform post-reaction processing; (iii) Fast; (iv) Confirmation of amplification in real time; (v) Specific, sensitive and reproducible; (vi) Simultaneous quantification of different pathogens.
(i) Ease of sample inoculation; (ii) Smaller size than conventional plates; (iii) Easy to discard (iv) Reduction of practical use and laboratory time; (v) Less employee training;
(i) Standardized method; (ii) “Gold standard” in food diagnostics; (iii) Do not require expensive infrastructure; (iv) Realistic results (similar bacterial quantification to the amount inoculated).
Disadvantages
(i) Competitive amplification (decrease of the efficiency and sensitivity in multiplex reaction); (ii) Need for qualified personnel; (iii) High cost of equipment; (iv) Do not distinguish living cells and dead cells.
(i) False positive results; (ii) Spends, at least, one day for results.
(i) Analyses are labor-intensive (ii) Require a lot of reagent media; (iii) Time consuming analysis (more than 3 days).
Purposes of use
Fast screening methods of large number of samples. Useful for microbiological quality control.
Screening method for bacterial enumeration. Useful for microbiological quality control.
Official method for food microbiological analysis. Useful for regulatory agencies.
Average of bacterial quantification (Salmonella, E. coli, and S. aureus) in ground beef, milk, and oyster meat. Salmonella was not quantified through Compact Dry and Traditional culture method.
