摘要：Contamination in commercially sold lunches by bacterial agents was examined during summer seasons by standard and simplyfied methods. A total viable count of 54.9% in 133 lunch samples was more than 104CFU/g; samples of the higher count were from chip-packed lunches (54.5%), supplied lunches (100%), onigiri (54.5%), and sushi (41.4%). The supplied lunch was found to be the most frequently contaminated. 72.2% of 133 samples were positive for coliforms with the highest percentage for the applied lunch (100%), observed on the basis of total viable counts. Staphylococcus aureus was detected in 29.3% of all the samples. The pathogen-pesitive percent for the chip-packed lunch, supplied lunch, onigiri and sushi was 27.7%, 30.0%, 27.3% and 34.5%, respectively. Bacillus cereus was detected in 44.4% of the samples. The pathogen-positive percent for the chip-packed lunch, supplied lunch, onigiri and sushi was 45.8%, 60.0%, 72.7% and 24.1%, respectively. The total viable count of the samples increased with the number of coliform-positive samples, but no relation could be found between contamination by S. aureus or B. cereus , and the increase in total viable count. The simplyfied method using a Hygicult-TPC for total viable count and a Sun Colitep for coliforms facilitated determination of bacterial contamination levels in the food samples.
