THE COMBINED EFFECT OF SODIUM LACTATE, LACTIC ACID AND ACETIC ACID ON THE SURVIVAL OF Salmonella spp. AND THE MICROBIOTA OF CHICKEN DRUMSTICKS

Abstract

The poultry processing industry has been investigating the new decontamination applications to prevent foodborne pathogens and extend the shelf life of poultry products. This study investigates the effects of lactic acid, acetic acid and sodium lactate, alone and in combination, on the survival of Salmonella spp. and the shelf life of chicken drumsticks. The fresh chicken drumsticks were inoculated with Salmonella Typhimurium and Salmonella Enteritidis and they were divided into groups as control (sterile tap water), 1% sodium lactate (SL), 1.5% lactic acid (LA), 1.5% acetic acid (AA), and their combinations. The drumstick samples were immersed into the treatment solutions for 5 minutes and stored at 4˚C for eight days, and they were analyzed for aerobic psychrotrophic bacteria (APB), Pseudomonas spp., lactic acid bacteria (LAB), Salmonella spp. and pH level. On day 5, APB, Pseudomonas spp. and LAB numbers exceeded 7.0 log10 CFU ml-1 in the control, SL, LA and LA+ SL groups. The reduction levels of Salmonella spp. were 1.2 and 0.9 log10 CFU ml-1 in the LA and AA+LA groups on day 0, and they were significantly different from the control group (P<0.05). The shelf life of the chicken drumsticks that were treated with the solutions containing 1.5% AA (AA, AA+ SL, AA+ LA and AA+ LA+ SL) was at least two days longer than the control group. It is concluded that the combinations of 1.5% LA, 1.5% AA and 1% SL can be used to reduce the number of Salmonella spp. and to extend the shelf life of chicken drumstick. Key words: chicken drumstick; lactic acid; acetic acid; sodium lactate; Shelf life; Salmonella spp. KOMBINIRANI UČINEK NATRIJEVEGA LAKTATA, MLEČNE KISLINE IN OCETNE KISLINE NA PREŽIVETJE Salmonelle spp. IN OSTALIH MIKROORGANIZMOV NA PIŠČANJIH BEDRIH Izvleček: Perutninsko predelovalna industrija raziskuje nove prilagoditve za dekontaminacijo mesa, da bi preprečila prenašanje patogenih mikroorganizmov s hrano in podaljšala rok uporabnosti perutninskih izdelkov. V opisani raziskavi so avtorji proučevali učinke mlečne kisline, ocetne kisline in natrijevega laktata, samostojno ali v kombinaciji, na preživetje Salmonelle spp. in na rok uporabnosti piščančjih beder. Sveža piščančja bedra so inokulirali s Salmonello typhimurium in Salmonella enteritidis ter jih razdelili v skupine: kontrolna skupina (z dodano sterilno vodo iz vodovoda), skupina z 1% natrijevim laktatom (SL), skupina z 1,5% mlečne kisline (LA), skupina z 1,5% ocetne kisline (AA) in njihovih kombinacij. Bedra so za 5 minut potopili v raztopine za obdelavo in jih osem dni hranili pri 4° C ter jih analizirali za prisotnost aerobne psihrotrofne bakterije (APB), Pseudomonas spp., mlečnokislinske bakterije (LAB), Salmonella spp. in pH-vrednosti. Peti dan so koncentracije APB, Pseudomonas spp. in LAB presegale 7,0 log10 CFU ml-1 v kontrolni skupini, skupini SL, LA in LA + SL. Znižanje ravni Salmonella spp. so bile 0, 1 in log10 CFU ml-1 v skupinah LA in AA + LA na dan 0 in so se bistveno razlikovale od kontrolne skupine (P <0,05). Rok uporabnosti piščančjih beder, obdelanih z raztopinami, ki vsebujejo 1,5% AA (AA, AA + SL, AA + LA in AA + LA + SL), je bil vsaj dva dni daljši od kontrolne skupine. Ugotovljeno je bilo, da lahko kombinacije 1,5% LA, 1,5% AA in 1% SL uporabimo za zmanjšanje števila Salmonella spp. in podaljšajo rok uporabnosti piščančjih beder. Ključne besede: piščančja bedra; mlečna kislina; ocetna kislina; natrijev laktat; rok uporabnosti; Salmonella spp.