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/cm2 and treated with the stock solution (HAMS),
the 1:5 diluted solution (MAMS), and the 1:10 diluted solution (LAMS) (stage 1). During the 20 min contact
time, the antimicrobial coatings reduced the Listeria populations by approximately 0.9–0.3 Log CFU/cm2
.
The higher the concentrations of the antimicrobial solution, the better the antilisterial effects were. The treated
inoculated beef samples were then stored at 4 °C for 30 days. During storage, Listeria growth inhibition effects
were seen. While no growth was seen from the HAMS-treated samples, a 1.6 Log CFU/cm2 increase was
seen for MAMS-treated samples, a 4.6 Log CFU/cm2 increase was seen for LAMS-treated samples, and a 5.7 Log
CFU/cm2 increase was seen for NoAMS-treated samples on Day 30 (~3 Log CFU/cm2 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 seen 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