Effect of lactic acid on Listeria monocytogenes and Edwardsiella tarda attached to catfish skin

Abstract

This study evaluated the use of lactic acid to decontaminate Listeria monocytogenes and Edwardsiella tarda attached to catfish skin with or without mucus. At the highest inoculum levels (104-105cfu skin-1), lactic acid (0.5-2.0%) exposure for 10 min reduced counts of L. monocytogenes firmly attached to catfish skin by O. 9- > 1.9 log10cfu skin-1and cells loosely attached by 2.7- > 3.7 logs. Counts of E. tarda firmly attached to catfish skin were reduced by 0.9- > 3.0 logs and cells loosely attached by 1.5- > 3.5 logs. Overall bacterial numbers of lactic acid-treated cells that were firmly attached to skin with mucus were higher than on skin without mucus. Firmly attached L. monocytogenes was more resistant to lactic acid than was firmly attached E. tarda. Catfish skin mucus decreased the antimicrobial effect of lactic acid against attached L. monocytogenes and E. tarda. © 2001 Academic Press.