Prevalence of Listeria contamination and its relationship with microplastics and Coliform in dairy products: a...

Listeria species are among the most significant foodborne pathogens, with dairy products providing a conducive environment for their growth and the potential development of listeriosis. This study aimed to investigate the prevalence of Listeria contamination in various dairy products and its relationship with coliform bacteria, as well as the association between Listeria contamination and microplastics in cheese packaging. A total of 179 samples, including different types of cheese and butter, were analyzed using chromogenic culture media, PCR, and actA gene identification. The presence of coliform contamination in these products was also examined. Additionally, 20 brands of cheese, resembling Italian cheese types, were selected for analysis. Cotton swab sampling was performed to detect biofilms on the surfaces of cheese packaging containing microplastics. PCR and dendrogram analysis revealed that Listeria monocytogenes was the most prevalent contaminant in cheese, with a strong association with the presence of the actA gene. Additionally, clustering and dendrogram analyses showed that Listeria innocua was the primary contaminant in butter samples. Microbial interaction network analysis and regression analysis further indicated a significant relationship between Listeria contamination and the presence of coliform bacteria in dairy products. Furthermore, a strong relationship was observed between Listeria contamination in cheese and the presence of microplastics in packaging. The actA gene plays a critical role in Listeria infections, particularly in relation to Listeria monocytogenes. A significant relationship was observed between Listeria contamination and coliform presence in dairy products, underscoring the need for rigorous monitoring to prevent foodborne illness. Future studies should further explore the interactions between microbial contaminants and microplastics.