Assessment of Microbial Source Tracking Marker and Fecal Indicator Bacteria on Food-Contact Surfaces in School Cafeterias

Abstract

Food poisoning outbreaks in schools can affect many students, causing physical and psychological damage and time and economic loss. Fecal indicator bacteria (FIB) have been used to monitor the contamination; however, the detection is time-consuming and confirms the contamination from all warm-blooded animals. Microbial source tracking (MST) is a molecular-based detection method that is host specific. This study aimed to evaluate MSTs and FIBs for tracing contamination in the school cafeteria. The average total aerobic count was 0.89 to 3.63 log CFU/100 cm2, and the faucets in the cooking area showed a significantly high aerobic count. The stove valve, faucet, and hand-washer were the most contaminated area, with a concentration of 1.90 to 6.80 log CFU/100 cm2 from the frequent hand contact. Escherichia coli was not detected on any surfaces, and coliform was detected on five surfaces: the sink and faucet in the food preparation area, the faucet in the cooking area, the hand-washer, and the toilet seat in the restroom with 0.33 to 3.64 log CFU/100 cm2. Human-specific crAssphage appeared on a faucet in the food preparation area, while HF183 was not detected. The result indicates that the continuous monitoring of frequent hand-contact areas is recommended to maintain the hygiene condition in the school cafeteria.

Keywords

• CrAssphage
• Human feces
• Microbial source tracking
• Real-time PCR
• School cafeteria