Effect of the lactoperoxidase system on Listeria monocytogenes behavior in raw milk at refrigeration temperatures.
Activity of raw milk lactoperoxidase-thiocyanate-hydrogen peroxide (LP) system on four Listeria monocytogenes strains at refrigeration temperatures after addition of 0.25 mM sodium thiocyanate and 0.25 mM hydrogen peroxide was studied. The LP system exhibited a bactericidal activity against L. monocytogenes at 4 and 8 degrees C; the activity was dependent on temperature, length of incubation, and strain of L. monocytogenes tested. D values in activated-LP system milk for the four strains tested ranged from 4.1 to 11.2 days at 4 degrees C and from 4.4 to 9.7 days at 8 degrees C. The lactoperoxidase level in raw milk declined during a 7-day incubation, the decrease being more pronounced at 8 degrees C than at 4 degrees C and in control milk than in activated-LP system milk. The thiocyanate concentration decreased considerably in activated-LP system milk at both temperatures during the first 8 h of incubation. LP system activation was shown to be a feasible procedure for controlling development of L. monocytogenes in raw milk at refrigeration temperatures.
Gaya
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P
Departamento de Producción y Tecnología de Alimentos, CIT-INIA, Madrid, Spain.
Medina
M
M
Nuñez
M
M
D000818:Animals; D003080:Cold Temperature; D015169:Colony Count, Microbial; D004355:Drug Stability; D004795:Enzyme Stability; D005516:Food Microbiology; D007784:Lactoperoxidase / Q000737:chemistry / Q000494:pharmacology*; D008089:Listeria monocytogenes / Q000187:drug effects* / Q000254:growth & development; D008892:Milk / Q000032:analysis / Q000382:microbiology*; D012034:Refrigeration; D013861:Thiocyanates / Q000494:pharmacology
D013861:Thiocyanates; D007784:Lactoperoxidase; C031760:thiocyanate