Inactivation of Escherichia coli K12 by pulsed UV light on goat meat and beef: microbial responses and modelling

Blue Light for Inactivation of Meatborne Pathogens and Maintaining the Freshness of Beef

ABSTRACT

Beef is rich in various nutrients but easily spoils due to bacterial contamination; thus, a bactericidal method is needed to inactivate meatborne pathogens while maintaining the freshness of beef. The present study was conducted to investigate for the first time the bactericidal effect of blue light (BL) at 415 nm against four meatborne pathogens (methicillin-resistant Staphylococcus aureus, Escherichia coli, Salmonella Typhimurium, and Listeria monocytogenes) both in vitro and inoculated onto the surface of fresh beef. The populations of the four pathogens on the nonirradiated control beef did not change significantly (P > 0.05), whereas a dose-dependent inactivation effect was found for BL-treated beef both in vitro and in vivo. On the beef cuts, BL at 109.44 J/cm2 inactivated 90% of inoculated cells of the tested strains (P < 0.05), and this inactivation effect was sustained during 7 days of cold storage. Insignificant changes in lipid oxidation rate, water holding capacity, and cooking loss were found during storage between the control beef and the beef irradiated at 109.44 J/cm2 at the same time. BL had a minor and nonsignificant effect on surface color and free amino acid concentrations. The pH of the treated beef increased more slowly (P < 0.05) than did that of untreated beef. These results suggest that BL could be a novel bactericide and could help maintain the freshness of beef.

HIGHLIGHTS

Preharvest Management and Postharvest Intervention Strategies to Reduce Escherichia coli Contamination in Goat Meat: A Review

Simple Summary

Goat farms and processing facilities worldwide are primarily small-scale, limited resource operations. Cost-effectiveness and practicality are critical factors to be considered before adopting any pre- and/or post-harvest strategies for pathogen reduction in goat meat. Preharvest management methods in goats that can reduce Escherichia coli in meat include minimizing animal stress, selecting diets and feed deprivation times that can reduce fecal shedding of bacteria, and adding tannin-rich feed supplements. In addition, use of appropriate postharvest nonthermal intervention technologies that can reduce microbial loads in carcasses and meat can extend the shelf-life and marketability of goat meat products. Reducing stress prior to slaughter and using nonthermal intervention methods can result in better meat quality and economic returns for producers.

Abstract

Goat meat is the main source of animal protein in developing countries, particularly in Asia and Africa. Goat meat consumption has also increased in the US in the recent years due to the growing ethnic population. The digestive tract of goat is a natural habitat for Escherichia coli organisms. While researchers have long focused on postharvest intervention strategies to control E. coli outbreaks, recent works have also included preharvest methodologies. In goats, these include minimizing animal stress, manipulating diet a few weeks prior to processing, feeding diets high in tannins, controlling feed deprivation times while preparing for processing, and spray washing goats prior to slaughter. Postharvest intervention methods studied in small ruminant meats have included spray washing using water, organic acids, ozonated water, and electrolyzed water, and the use of ultraviolet (UV) light, pulsed UV-light, sonication, low-voltage electricity, organic oils, and hurdle technologies. These intervention methods show a strong antimicrobial activity and are considered environmentally friendly. However, cost-effectiveness, ease of application, and possible negative effects on meat quality characteristics must be carefully considered before adopting any intervention strategy for a given meat processing operation. As discussed in this review paper, novel pre- and post-harvest intervention methods show significant potential for future applications in goat farms and processing plants.