Microbial threats in raw food products: prevalence of bacterial pathogens

Abstract

Food safety has emerged as a major global public health concern due to microbiological risks associated with raw food products. This study aimed to determine the prevalence of bacterial pathogens in raw beef, raw chicken, fish, leafy greens (lettuce, parsley, spinach), and raw milk samples collected in Kocaeli, Türkiye, between May and October 2024. A total of 220 samples were analyzed using standardized microbiological methods for Escherichia coli, Staphylococcus aureus, Salmonella spp., Listeria monocytogenes, and Shigella spp. The colony counts were determined and expressed as CFU/g or CFU/mL according to ISO protocols. E. coli was detected in 59.54% of the samples analyzed, S. aureus in 31.81%, Salmonella spp. in 10%, and L. monocytogenes in 0.9%. The detected microbial counts, particularly for E. coli and S. aureus, exceeded the limits established by the Turkish Food Codex and EU regulations for raw food products, indicating potential health risks. The elevated microbial counts may be explained by hygiene deficiencies during production, handling, and storage, including inadequate sanitation, contaminated equipment, and environmental exposure. E. coli was the most frequently detected bacterium, particularly in raw milk (80%) and leafy greens (75%). Salmonella spp. was mainly found in raw chicken (17.5%) and fish meat (11.9%), while S. aureus was most prevalent in raw milk (53.33%) and fish meat (47.61%) samples. L. monocytogenes was detected at low levels only in raw beef (2.04%) and raw chicken (2.5%), while Shigella spp. was not detected in any of the samples. The results suggest that hygiene deficiencies may be among the potential factors contributing to contamination, along with other possible contamination sources throughout the production and handling chain.