Investigating meat-borne bacterial profiles related to biofilm formation: An in situ and in vitro assessment

Abstract

Foodborne spoilage bacteria may pose a serious risk to food quality by forming biofilms that adhere to food processing devices and food surfaces, thus causing cross-contamination and deterioration of food products. In order to effectively control microbial contamination, understanding the bacterial profiles related to biofilm formation in situ is crucial. Pseudomonas, Aeromonas, and Serratia are typically considered as prevalent spoilage organisms in chilled meat, which is particularly susceptible to deterioration during storage and transportation. In this study, four strains (Serratia liquefaciens F5, Aeromonas salmonicida H8, Pseudomonas saponiphila G7, and Aeromonas veronii G8) were cultured in situ in chilled chicken claws as the experimental group and in Tryptic Soy Broth (TSB) as the control group. The results showed that tested strains differed in ability to adhere, with S. liquefaciens F5 significantly exhibiting the highest biofilm formation capacity (P < 0.05). Moreover, it was discovered that higher protein and polysaccharides concentrations enhanced bacterial auto-aggregation and that the protein content of extracellular polymeric substances (EPS) positively correlated with bacterial surface hydrophobicity. On the 4th day, the protein content in EPS of each strain was significantly higher in vitro than in situ (P < 0.05). Furthermore, the rate of increase in auto-aggregation capacity and surface hydrophobicity proved faster in vitro than in situ for each strain due to higher polysaccharides and protein contents. The primary components (proteins, polysaccharides) in the EPS of the four strains increased as the biofilm formation process progressed, further confirmed by Attenuated Total Reflection Fourier Transform Infrared Spectroscopy (ATR-FTIR) spectra. Scanning electron microscopy revealed that A. salmonicida H8 can create biofilms on the surface of chicken claws, which severely disrupts the tissue structure of chilled meat. These observations will offer a theoretical foundation for a thorough investigation of the spoiling outcomes and adhesion characteristics of various meat-derived spoilage bacteria.