Sample analysis
The swab samples were shaken in 10ml
Quarter Strength Ringer’s Solution for 30
seconds to resuscitate metabolically injured
bacteria, followed by serial dilutions. The
spread plate technique was used to prepare
duplicate plates for the determination of to-tal aerobic plate counts (APC), Enterobacteriaceae
counts (EC), Staphylococcus aureus
and Bacillus cereus counts. Aerobic plate
counts (APC) was made on plate count agar
(Oxoid CM463) at 35oC for 72h. Counts of
Enterobacteriaceae, Staphylococcus aureus, and
Bacillus cereus were made using Violet Red
Bile Lactose agar (Oxoid CM107), Baird–
Parker agar (Oxoid CM275) and B. cereus
selective agar (Oxoid CM617) respectively.
After appropriate incubation, dilutions with
30–300 colonies were selected and counted.
Predominant colonies were picked and purified
on Nutrient Agar plates. The number
of colony-forming units per gram (cfu/g) of
food was calculated by multiplying the
number of bacteria by the dilution.