Survival of Escherichia coli O157 : H7 on vacuum-packaged raw beef treated with polylactic acid, lactic acid, and nisin

The antimicrobial effect of 2% low molecular weight polylactic acid (LMW-PLA), 2% lactic acid (LA), 200 IU nisin (Nisaplin(TM))/mL, and combinations of nisin and each acid on Escherichia coli O157:H7 on raw beef was investigated. Fresh beef, inoculated with E. coli O157:H7 and treated with each solution, was vacuum packaged and stored at 4degreesC for 28 d. At day 28, counts of samples treated with LMW-PLA, NPLA, LA, and NLA were significantly reduced to 3.13, 2.91, 2.99, and 2.83 log(10) CFU/cm(2), respectively. However, the antimicrobial effect of LMW-PLA and LA was not significantly different from each other and Nisaplin did not enhance the effects of either acid against this organism.