Detecting and Identifying Bacterial Contamination in School Canteens in Al-Marj City, Libya

Abstract

School canteens constitute an important component of the food supply system for children and may represent potential sources of foodborne infection when appropriate hygiene and sanitation practices are not maintained. Food handlers, food-contact surfaces, and water sources can contribute to the transmission of pathogenic microorganisms. This study investigated the occurrence and distribution of bacterial contamination in selected school canteens in Al-Marj City, Libya.

A cross-sectional study was conducted between January and April 2025 in selected public and private school canteens in Al-Marj City. A total of 60 swab samples were collected from 15 school canteens, with four samples obtained from each canteen. Sampling sites included food handlers’ hands, food preparation surfaces, food preparation tables, and water sinks. Samples were transported under refrigerated conditions to the laboratory and subjected to microbiological examination, including culture, Gram staining, and conventional biochemical tests for bacterial identification.

Bacterial growth was detected in 32 of the 60 samples, corresponding to an overall contamination rate of 53.33%. Gram-negative bacteria accounted for 21 isolates (65.63%), whereas Gram-positive bacteria accounted for 11 isolates (34.37%). Among the identified organisms, Escherichia coli was the predominant isolate, comprising 14 isolates (43.75%), followed by Staphylococcus aureus with 11 isolates (34.38%) and Proteus mirabilis with 7 isolates (21.88%). E. coli was detected across all sampling locations, with the highest proportion reported from the snack/food-service table and water sink. S. aureus was most frequently recovered from the snack/food-service table, whereas P. mirabilis was primarily detected on food preparation and snack/food-service surfaces.

The detection of bacterial contamination in more than half of the sampled canteen sites indicates important deficiencies in hygiene and sanitation practices. The predominance of E. coli, S. aureus, and P. mirabilis highlights potential risks associated with inadequate hand hygiene, contaminated food-contact surfaces, and insufficient sanitation of water-related areas. Strengthening hygiene training for food handlers, improving cleaning and disinfection procedures, and implementing routine microbiological surveillance are recommended to reduce the risk of foodborne illness among schoolchildren.