Survival of Listeria monocytogenes in a simulated recirculating brine chiller system

• Published in: Journal of food protection 2003-10, Vol.66 (10), p.1840-1844
• Main Authors: Gailey, J.K, Dickson, J.S, Dorsa, W
• Format: Article
• Language: English
• Subjects: bacterial contamination; Biological and medical sciences; brining; Chlorine - pharmacology; Colony Count, Microbial; cooling systems; Dose-Response Relationship, Drug; food contamination; Food Handling - instrumentation; Food Handling - methods; Food industries; food pathogens; food processing equipment; food safety; Fundamental and applied biological sciences. Psychology; hot dogs; Hydrogen-Ion Concentration; Hygiene; inoculum density; Listeria monocytogenes; Listeria monocytogenes - growth & development; Meat and meat product industries; Meat Products - microbiology; pathogen survival; plate count; postcooking contamination; processed foods; recirculating aquaculture systems; salt concentration; Salts - pharmacology; sodium chloride
• ISSN: 0362-028X; 1944-9097
• DOI: 10.4315/0362-028X-66.10.1840

Contamination by Listeria monocytogenes of processed meats after cooking presents a significant food safety risk. The purpose of this study was to determine the survival of L. monocytogenes in a simulated recirculating brine chiller system using pH values of 5, 6, and 7 with free chlorine concentrations of 0, 3, 5, and 10 ppm in 20% salt brine at -12°C. At pH values of 5, 6, and 7 with chlorine concentrations of 2 and 3 ppm, using 10(8) CFU in a test tube system, an immediate drop of 0.28 log CFU/ml with no significance between treatments (P > 0.05), followed by a steady survival phase with a slope close to 0, was observed. In brine at a pH of 5 with 5 and 10 ppm of chlorine, an initial drop of 0.8 log CFU/ml was observed, which was followed by a steady survival phase with a destruction slope close to zero. At an inoculation concentration of 10(2) CFU in a test tube system (pH values of 5 and 7 with 0 and 10 ppm of chlorine), the average initial drop for all treatments was 0.1 log CFU/ml, which was followed by a steady survival phase. In a recirculating system, very few cells were destroyed during the brine chilling process, but only low numbers of L. monocytogenes were recovered from the brine and uninoculated hot dogs. Although little destruction of L. monocytogenes was noted, the dilution effect observed during the study indicates that environmental contamination of a brine chiller system poses little danger of postcooking contamination for processed meats if the system is regularly cleaned and sanitized.