Comparison of biofilm formation between non-pathogenic Listeria strains under different stress conditions

Abstract

Micro-organisms can attach to food surfaces and develop biofilms which present a concern in food and environmental safety. The main goal of the current study was to investigate the biofilm formation of six non-pathogenic Listeria strains under different stress conditions using a microplate assay. The effect of the weak biofilm-forming non-pathogenic Listeria strains on the biofilm formation of a strong biofilm-forming pathogenic Listeria strain (Listeria monocytogenes #8) was also examined. Listeria innocua CCM4030, Listeria innocua 2885 and Listeria seeligeri/welshimeri 292 showed the same patterns of biofilm formation with increasing NaCl concentrations from 0.05 to 15%, but all the other strains showed a continuously decreasing trend of OD595 in the same conditions. This study showed that in the case of non-pathogenic Listeria strains, higher concentrations of NaCl do not present a stress condition that enhances biofilm formation. Decrease in pH inhibited biofilm formation for all the non-pathogenic Listeria strains. The weak biofilm forming non-pathogenic Listeria strains (Listeria innocua 2885 and Listeria innocua CCM4030) overgrew the strong biofilm-forming Listeria strain (Listeria monocytogenes #8) during biofilm formation. This phenomenon could be beneficial and potentially be used as a novel control strategy to prevent the colonization of the pathogenic Listeria at food processing facilities such as in meat industry.

Effect of lactic acid and lysozyme on river fish fillets during cold storage

“…Studies proved that fishes are continuously exposed in nature to a wide range of microorganisms, particularly in water and their feed (Ringø and Gatesoupe, 1998). Additionally, minimally processed food might be infected in the supply chain as well (Hasani et al, 2020;Kim and Marshall, 2001). According to recent studies in the topic, there is high demand for standard protocols preventing severe contamination and maintaining quality as long as possible (Nogueira et al, 2019;Park et al, 2017).…”