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Isolation and Selection of Lactic Acid Bacteria as Biocontrol Agents for Nonacidified, Refrigerated Pickles

Reina, Laura D., Breidt, Fred, Jr., Fleming, Henry P., Kathariou, Sophia
Journal of food science 2005 v.70 no.1 pp. M7
Enterococcus, Lactobacillus curvatus, Lactococcus, Leuconostoc, Listeria monocytogenes, Weissella, biological control, biological control agents, blanching, brining, competitive exclusion, cucumbers, fruits, lactic acid bacteria, pathogens, pickles, pickling, spice oils, temperature
A nonacidified, deli‐type pickle product was used as a model system to study the potential use of biocontrol as a means to prevent the growth of pathogens in minimally processed fruits and vegetables (MPFV). Fresh pickling cucumbers were blanched and brined with sterile spices and garlic oil. The product was stored at 5 °C for 3 wk and then transferred to various abuse temperatures (16 °C, 25 °C, 30 °C). Lactic acid bacteria (LAB) were isolated and characterized as potential biocontrol agents, and the isolates were tested for bacteriocin‐like activity. A total of 118 LAB isolates were obtained. Among the LAB identified were species of Lactococcus, Leuconostoc, Lactobacillus, Weissella, and Enterococcus. Three isolates showed transient bacteriocin activity against—Listeria monocytogenes, and 7 isolates (Lactococcus) had bacteriocin‐like activity against other LAB. Although it did not produce a bacteriocin, a Lactobacillus curvatus isolate (LR55) was found to have desirable characteristics for use as a biocontrol (competitive exclusion) culture to enhance the safety of nonacidified deli‐type pickles.