89D-9 |
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R. BEVERLY, M. E. Janes, and W. Prinyawiwatkul. Dept. of Food Science, Louisiana State Univ. Agricultural Center, 111 Food Science Bldg., Baton Rouge, LA 70803-4200 Chitosan is a biopolymer that has antimicrobial properties against foodborne pathogens and could possibly be used to control Listeria monocytogenes (Lm) on the surface of ready-to-eat (RTE) meat products. Our study investigated the use of chitosan as an edible coating for the control of Lm on the surface of RTE roast beef (RB). An 18h Lm culture was decimally diluted and 1 ml was inoculated onto the surface of RTE RB cubes (5g). The samples were allowed to air dry for 1h then dipped into high (HMW) or low (LMW) molecular weight chitosan solutions that were dissolved with acetic (AA) or lactic acid (LA) at 0.5% or 1% concentration. The samples were refrigerated at 4oC and bacterial counts determined on day 0, 7, 14, 21, and 28. Samples examined by plating onto Oxford agar plates, incubating at 37°C for 48 h and determining the Log CFU/g. An initial 6.5 Log CFU/g of Lm inoculated onto the surface of the non-coated RTE RB had grown to 11.50 Log CFU/g by 28 days. On day 7, all chitosan coated RTE RB Lm counts were significantly different from the control counts and remained significantly different through-out the study. By day 21 the 1.0% LA LMW chitosan reduced Lm counts by 1.06 Log CFU/g whereas 1.0% AA LMW chitosan reduced Lm counts by 3.13 Log CFU/g on the surface of RTE RB. By day 28 the most effective coatings were the AA chitosan reducing Lm counts on the surface of RTE RB from 2.20 to 3.30 Log CFU/g. The control AA and LA treated RTE RB had reduced Lm counts by 1.30 Log CFU/g on the surface of RTE RB by day 28. Our study indicated that chitosan coatings could be used to control Lm on the surface of ready-to-eat roast beef.
Session 89D, Food Microbiology: Antimicrobial effects on foodborne microorganisms
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |