Research – Role of blue light in bactericidal effect against meat-borne pathogens and freshness maintaining of beef 

Journal of Food Protection

Beef is rich in various nutrients while easily spoils due to contamination by pathogens, thus it is of great significance to develop a bactericidal method to inactivate meat-borne pathogens and meanwhile maintain the freshness of beef. For the first time, the present study investigated the bactericidal effect of blue light (BL) at 415 nm against four meat-borne pathogens (methicillin-resistant Staphylococcus aureus , Escherichia coli , Salmonella Typhimurium and Listeria monocytogenes ) in vitro and inoculated on the surface of fresh beef, respectively. When the non-illuminated beef was used as control, the population of the four pathogens did not change significantly ( P > 0.05), while BL-illuminated beef showed dose-dependent inactivation effect in both in vitro and in vivo studies. The experiments on beef cuts showed that 109.44 J/cm 2 of BL inactivated 90% of inoculated cells for the tested strains ( P < 0.05), and the impact of BL inactivation could be sustained in 7 days of cold storage. Notably, changes of lipid oxidation rate, water holding capacity and cooking loss value between the control and beef illuminated by 109.44 J/cm 2 at the same time were scarcely detected during the storage. BL had a minor but insignificant influence on surface color and free amino acid content. Moreover, the pH of illuminated beef increased slower ( P < 0.05) than that of non-illuminated beef. The present work demonstrated that BL could be a novel bactericidal and freshness-maintaining method for fresh beef.

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