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Growth and Case Studies. Roy Biggs Tegel Research and Case Studies Research on growth of Listeria in products; chicken roll, chicken bacon and pre-cooked sausages Tegel experience – case studies. Background - NZ.
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Growth and Case Studies Roy Biggs Tegel Research and Case Studies • Research on growth of Listeria in products; chicken roll, chicken bacon and pre-cooked sausages • Tegel experience – case studies
Background - NZ • Tegel is the largest producer of cooked chicken products in NZ – over 150 tonnes per week, up to one third of this is chilled, long shelf life products • Last Tegel recall for micro contamination was in January 2000
The Research - 1 • Objective – to test our assumptions (models) on consequences if contamination occurred. • 3 products • Sliced chicken roll • Chicken bacon • Pre-cooked sausages
The Research - 2 • Innoculate them with <100 per g of Listeria • Incubate at 2oC & 10oC and test fortnightly • Plot the growth • Be scared, be very, very scared!
The Research - Conclusions • If we have a low level of contamination it is serious • Need to concentrate our efforts on prevention and monitoring • Be scared, be very, very scared!
The Incidents - 1 • Product – chicken tenders • Dedicated cook plant with excellent separation & facilities • Isolation 1 – shift changeover – repair • Isolation 2 – shift changeover – wash • Isolations 3 & 4 – intermediate washes • Conclusions – conveyor, mandated wash
The Incidents - 2 • Product – shredded chicken • Dedicated cook plant with excellent separation but poor entry facilities • Isolation 1 – product produced on nightshift • Isolation 2 – 6 days later on same shift • Isolation 3 – over next 7 days 37/160 • Conclusion – shaft seal on dicer
The Incidents - 3 • Dedicated cook plant with excellent separation & entry facilities • Poor maintenance led to Lm isolations from floors over a period of months, shutdown planned in 3 months • No product isolations and product testing increased to 5 per line per day • NZFSA instruction to cease processing
The incidents – 3 - continued • Negotiated continuation of processing for most products with increased sampling and supervision by Tegel technical staff • Maintenance shutdown 2 weeks later • Sporadic incidents over the next few months followed by “deep” cleans • DNA typing • No isolations for the following 2 years
The Current Monitoring Regime • Pre-start physical check daily & ATP monitoring • First product off the line for all sliced and shredded products • Product samples and PC swabs at start up, 25%, 50% and 75% of the production run and during the last hour. • Non PC swabs (up to 20 locations) during last 2 hours of production • Any Intermediate cleans followed by product samples, PC and non-PC swabs • Escalation response
Guidance • Control of Listeria monocytogenes in the Food Processing Environment – R. B. Tompkin (2002)Journal of Food Protection, vol 65 No4, pages 709-725 • Listeria Guidelines MAF