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MICROBIAL CHANGES ON FRESHLY SLAUGHTERED PORK CARCASSES DUE TO “HOT” LACTIC ACID DECONTAMINATION
Author(s) -
NETTEN P.,
MOSSEL D.A.A.,
HUIS J.H.J.
Publication year - 1997
Publication title -
journal of food safety
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.427
H-Index - 43
eISSN - 1745-4565
pISSN - 0149-6085
DOI - 10.1111/j.1745-4565.1997.tb00179.x
Subject(s) - human decontamination , lactic acid , food science , chemistry , microbiology and biotechnology , biology , bacteria , waste management , genetics , engineering
We studied the microbial changes on fresh (still warm) pork carcasses immediately after electrostatic spraying of lactic acid solutions and during chilled storage. Lactic acid decontamination (LAD) included electrostatic spraying of hot (55C) solutions of 1% lactic acid for 90 s and 2%‐ and 5% lactic acid for 30 and 90 s. The treatments increased the carcass surface temperature from 22C to about 32–43C. The bactericidal activity of lactic acid killed mainly Gram‐negative bacteria. Reductions in “total” psychrotrophic Gram‐negative and Entero‐bacteriaceae counts were found reliable indicators for the efficacy of LAD. Hot 2–5% LAD treatments achieved overall reductions in Gram‐negative psychrotrophs ranging from 0.8 to more than 1.4 log 10 cfu per cm 2 . Overall reductions in mesophilic Enterobacteriaceae counts ranged from approximately 1.2 to more than 1.8 log 10 cfu per cm 2 . Treatments with 1% lactic acid achieved marginal 0.5–0.6 overall log 10 reductions in these groups of organisms. Bactericidal effects after LAD occurred during a lag period of whose duration increased with the lactic acid concentration of the spray solution. The lag lasted less than 1 day on 1% LAD, 2 days on 2% LAD and 4 days on 5% LAD meat. During these lags the meat surface pH rose from pH 2.7 to 3.2 immediately after LAD to pH 4.8 to 5.2. During aerobic chilled storage after LAD the growth of Gram‐negative psychrotrophs was controlled only temporarily. These organisms became the dominant group of organisms. The practical utility of electrostatic spraying of fresh pork carcasses with hot 1–5% LAD to improve the keeping quality is questionable .