Formation of Shewanella putrefaciens biofilms on nylon film and effects on putrefaction of large yellow croaker

Abstract

Biofilms formed on food contact surfaces cause significant economic loss in the food sector and pose a serious public health concern. In this study, the formation of Shewanella putrefaciens (S. putrefaciens) biofilms on nylon film at 30°C and 4°C was investigated. Results indicated that more biofilms were formed at 4°C, which peaked after 60 h incubation. The protease activity in biofilms was significantly higher than that in the corresponding plankton culture, and it was closely related to the development stage of biofilms. Besides, S. putrefaciens biofilms formed on nylon film in large yellow croaker juice and fresh cubes at 4°C were also investigated, and SDS-PAGE patterns demonstrated that S. putrefaciens biofilms showed a higher capacity to decompose proteins than planktonic bacteria. This work provided insight into the development of biofilms on nylon film, allowing for further controlling S. putrefaciens biofilms in food packages in the future. Practical applications Flexible plastic packaging with nylon film is widely used for packaging perishable food products including marine fish, smoked fish, processed meats such as sausage and bacon, dairy products, and prepared ready meals due to its various advantages of thermoformability, mechanical strength and toughness, transparency, and oxygen barrier properties. However, the formation of biofilms on the packaging surfaces can cause significant economic loss in the food industry and pose serious public health concerns. This study compared the formation of Shewanella putrefaciens biofilms on nylon film at 30°C and 4°C, and the results can provide further insight into the development of biofilms on nylon film, allowing for better control of S. putrefaciens biofilms in food packages, which is thus very beneficial for the food industry and consumers to ensure food safety.