摘要：Staphylococcus aureus , a common human pathogen, produces enterotoxin and causes intoxication when ingested through contaminated food. The aim of the present study was to investigate microbiological quality of pizza and to detect the presence of the pathogenic S. aureus in this food. Moreover, effects of gamma radiation and low temperature on inoculated pathogenic S. aureus in pizza were examined. For this purpose, 20 pizza samples were collected from 5 different shops to check the microbiological quality and the presence of S. auresu . Isolated S. aureus were then checked for toxin production by mice assay. Pre-sterilized pizza samples inoculated with toxin producing isolate were then subjected to different gamma radiation doses and kept at refrigerator followed by detecting the presence of viable S. aureus . Among the collected pizza samples, 18 samples showed the presence of high number of total bacterial count, coliform count and staphylococcal count. Microwave heating could completely eliminate the viable counts only after 2 min. Among the isolated Staphylococcus spp., 13 isolates were identified as pathogenic S. aureus and one isolate produced deadly toxin. Radiation dose of 8 kGy resulted in the total elimination of S. aureus inoculated in pizza samples. However, low temperature (4°C) storage after gamma radiation showed a drastic change on the growth of the organism. The shelf life of these pizza samples was also extended up to 14 days. Thus, irradiation at 8 kGy with combination of storage at 4°C could be the suggested treatment for the storage of such ready-to-eat food without presence of pathogenic S. aureus .
