|WANG, LUXIN - Auburn University|
|ZHAO, LIANG - Auburn University|
|YUANG, JING - Auburn University|
Submitted to: International Journal of Food Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/9/2015
Publication Date: 8/6/2015
Citation: Wang, L., Zhao, L., Yuang, J., Jin, Z.T. 2015. Application of a novel antimicrobial coating on roast beef for inactivation and inhibition of Listeria monocytogenes during storage. International Journal of Food Microbiology. 211:66-72.
Interpretive Summary: Although ready-to-eat (RTE) meats contain salts such as sodium chloride, nitrite and nitrate that have antimicrobial activities, they do not inhibit the growth of pathogenic L. monocytogenes during storage at refrigeration temperatures. Therefore, antimicrobial coating on the meat surface is an additional means to decontaminate Listeria on RTE meats. This study demonstrates the effectiveness of antimicrobial coatings with a novel formulation against L. monocytogenes inoculated on roast beef. The findings of this study may provide a new approach for applications of this proposed coating solution in deli counters or consumers’ homes as a meat coating or spray to better ensure the safety of ready-to-eat meat products.
Technical Abstract: The antilisterial efficacy of novel coating solutions made with organic acids, lauric arginate ester, and chitosan was evaluated in a three-stage study on inoculated roast beef for the first time. Ready-to-eat roast beef was specially ordered from the manufacturer. The meat surface was inoculated with five-strain Listeria monocytogenes cocktail inoculums at two different levels, 3 and 6 Log CFU and treated with the stock solution (S1), the 1:5 diluted solution (S2), and the 1:10 diluted solution (S3) (stage 1). During the 20 min contact time, the antimicrobial coatings reduced the Listeria populations by approximately 0.9–0.3 Log CFU. The higher the concentrations of the antimicrobial solution, the better the antilisterial effects were. The treated inoculated beef samples were then stored at 4 degree C for 30 days. During storage, Listeria growth inhibition effects were observed. While no growth was seen from the S1-treated samples, a 1.6 Log CFU increase was observed for S2-treated samples, a 4.6 Log CFU increase was observed for S3-treated samples, and a 5.7 Log CFU increase was observed for control samples on Day 30 (3 Log CFU inoculation level). In the second stage, the impact of the roast beef storage time on solution's antilisterial effect was evaluated. Results showed that the effect of the antimicrobial solution was dependent on both the initial inoculation levels and storage times. In stage 3, the effect of the antimicrobial solution on roast beef quality was studied with both instrument measurement and sensory evaluation. Minor changes in color, pH, and water activity were found. However, only limited sensory differences were found between the treated and untreated samples. When panels were able to accurately find color differences between samples, they preferred the treated samples. The findings of this research proved the antilisterial efficacy of the novel antimicrobial solution and showed its potential for being used as a roast beef cut surface coating to control Listeria contamination and for color protection.