17H-5 |
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Z. LIU1, B. Swem2, and Y. Li1. (1) Department of Biological and Agricultural Engineering, University of Arkansas, O-419 Poultry Science Building, Fayetteville, AR 72701, (2) Center of Excellence for Poultry Science, University of Arkansas, O-420 Poutry Science Building, Fayetteville, AR 72701 Recirculated brine is widely used as chilling medium for ready-to-eat meat products, but it may cause post-cooking microbial recontamination. USDA recommends maintaining a chlorine concentration of 1-5 ppm in recirculated brine. However, it is difficult to keep a desired concentration of chlorine during the chilling process because organic solids at high concentration consume chlorine quickly. The objectives of this research were to design a pilot-plant-scale in situ chlorine generation system and to evaluate its antibacterial effect on recirculated chilling brine. Bacon brine and hot dog brine (150 L) were recirculated in the portable chiller system from ALKAR for 4 days continuously at –4 ± 1 °C. Listeria innocua was inoculated into the bacon brine at a level of 106 log CFU/ml and 3 A DC current was applied to the chambers throughout the chilling process. For the hot dog brine, 3 log CFU/ml L. innocua was inoculated at every 2nd, 3rd, or 4th h, and simultaneously 13.5 kg naked fresh hot dog was placed in the chiller. 8-10 ppm free chlorine was kept in the hot dog brine by adjusting the electric current. Brine and hot dog samples were tested for both total aerobic microorganisms and L. innocua using direct plating and MPN method, respectively. 6 log MPN/ml reduction of L. innocua in 12 h and 3 log CFU/ml reduction of total aerobic microorganisms in 23 h were obtained in the recirculated bacon brine. For the hot dog brine, a reduction rate of 1.5 log MPN/ml per min for L. innocua was obtained and no microbially recontaminated hot dog was found during the whole chilling process. The results indicated that the flow-through electrolyzing system could effectively reduce microorganisms and prevent recontamination of ready-to-eat food products during chilling process by keeping a steady concentration of chlorine in the recirculated chilling brine.
Session 17H, Food Engineering: Thermal processes
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