POTENTIAL OF LACTOBACILLUS-CASEI, CULTURE PERMEATE, AND LACTIC-ACID TO CONTROL MICROORGANISMS IN READY-TO-USE VEGETABLES

The effects of various treatments (i.e., the addition of a strain of L actobacillus that produces antimicrobial agents, Lactobacillus casei I MPC LC34, its sterile permeate, and 0.5 or 1% lactic acid) on the grow th of microorganisms associated with ready-to-use mixed salad vegetabl es were compared during refrigerated (8 degrees C) storage. The additi on of 3% culture permeate to mixed salads reduced the total mesophilic bacteria counts from 6 to 1 log CFU/g, and suppressed coliforms, ente rococci, and Aeromonas hydrophila after 6 days of storage at 8 degrees C. A similar effect was shown when the L. casei culture was inoculate d in the vegetables. One percent lactic acid had a bacteriostatic effe ct on the bacterial groups examined, except for total and fecal colifo rms, which were reduced by about 2 and 1 log unit, respectively, while 0.5% lactic acid did not affect the indigenous microflora of the vege tables. The potential of these new hurdles to prevent the growth of sp oilage and pathogenic bacteria in ready-to-use salad vegetables is sug gested.