Efficacy Evaluation of Control Measures on the Reduction of Staphylococcus aureus in Salad and Bacillus cereus in Fried Rice Served at Restaurants

摘要

The objective of this study was to assess the effect of washing on Staphylococcus aureus reduction in salads and the effect of reheating on Bacillus cereus vegetative cells and spores reduction in fried rice at restaurants using the stochastic food safety objective (FSO) tool. The leaf vegetable was inoculated with S. aureus and washed with tap water, 100ppm of NaClO, or 30ppm of slightly acidic electrolyzed water (SAEW) for either 60s or 5min. The washing effect of 30ppm SAEW was greater than that of 100ppm NaClO. Based on the FSO concept, washing leaf vegetables with 30ppm SAEW for 5min was the most efficient control measure for S. aureus in salads. In addition, the salad should be consumed within 4h at 25 degrees C and 2h at 35 degrees C after 5min of washing with 100ppm NaClO or 30ppm SAEW. The fried rice was first inoculated with B. cereus vegetative cells or spores and was then reheated in a frying pan at medium (internal temperature of fried rice: 69.2 degrees C-78.8 degrees C) or high heat (internal temperature of fried rice:103.8 degrees C-121.4 degrees C) or in a microwave oven (internal temperature of fried rice:86.3 degrees C-90.6 degrees C) for 3 or 4min. Based on the FSO, reheating rice in a microwave oven was the most efficient control measure for B. cereus vegetative cells and spores in fried rice. The holding time for fried rice can be extended up to 6h at 25 degrees C, 3h at 35 degrees C, and 2h at 45 degrees C with reheating. Microbiological hazards in salads and fried rice can be controlled by washing with a sanitizer and reheating, respectively and then by controlling of holding temperature before being served at restaurants.