29G-23 |
Study of Listeria monocytogenes survival/inactivation on a new conveyor design |
J. WELLER1, A. A. Lathrop1, S. FEDERSPIEL2, M. A. Cousin1, and A. K. Bhunia1. (1) Dept. of Food Science, Purdue Univ., 745 Agriculture Mall Dr., West Lafayette, IN 47907-2009, (2) Shuttleworth Inc., 10 Commercial Rd., Huntington, IN 46750 Conveyor systems are used in the food processing industry to transport raw or processed foods throughout a factory. Since processed foods are transferred often the ability to sanitize them is important. The goal of this project was to determine the potential for contamination, survival and decontamination of the new conveyor design. The conveyor prototype (19.5”× 11.5” × 6”) used for the challenge study was manufactured locally. This conveyor was placed inside a biosafety cabinet and inoculated with Listeria monocytogenes(LM), at concentrations from 103 to 106 cells/ml. The conveyor was run for one hour and then sprayed with luke warm tap water using a hose. Then the conveyor was sanitized using MatrixxTM or OxoniaTM sanitizers prepared according to the manufacturers recommendations and the conveyor was allowed to run for ten more minutes. Swabs were taken from various areas of the conveyor, placed into Modified Listeria Enrichment Broth, and incubated for 72 hours. Positive swab samples were confirmed by the genomic fingerprinting system (Riboprinter®) Positive samples were recorded after 24, 48, and 72 h. Trials with 106 cells/ml inoculation and without sanitizers, swab samples were positive 65.3% of the time. Following OxoniaTM application 3.41% of the swabs were positive, while with MatrixxTM application 1.54% were positive. No positive swabs were found after sanitizer treatment when inoculated with 103 LM cells/ml. All positive samples had similar genetic fingerprint patterns as the inoculated strain. Overall, the new conveyor was easy to clean, showing little to no survival of the LM applied. Positive samples from trials in which no sanitizer was applied confirmed that the LM could survive in various parts of the conveyor. Positive samples from trials in which sanitizers were applied were likely due to improper application of the sanitizers that did not contact all areas of the conveyor.
Session 29G, Food Microbiology: General
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