10/18/2017 Susceptibility to physical and Listeriosis and foods chemical agents Ready-to-eat foods What foods are risky? Grows well and survives in 6.5%salt Pose a high listeriosis risk Lowering temperature increases survival for susceptible populations in high salt .20%of refrigerators have temperatures greater than Control of Listeria is best achieved by 50F multiple hurdles and environmental Refrigeration cannot ensure the safety of monitoring ready-to-eat foods Refrigeration is an environment where Listeria can outcompete mesophilic pathogens Listeriosis and foods Listeriosis and foods Milk Cheeses Raw milk is a source of L.monocytogenes L.monocytogenes survives cheese Pasteurization reduces the numbers of manufacturing and ripening Lm Temperature hardy,grows in the cold and Post-process milk contamination is a salt tolerant concern as Listeria grows faster in Soft cheeses are a risk factor for pasteurized milk than in raw milk due to listeriosis fewer competitors10/18/2017 5 Susceptibility to physical and chemical agents • Grows well and survives in 6.5% salt • Lowering temperature increases survival in high salt • Control of Listeria is best achieved by multiple hurdles and environmental monitoring Listeriosis and foods Ready-to-eat foods • Pose a high listeriosis risk for susceptible populations • 20% of refrigerators have temperatures greater than 50oF • Refrigeration cannot ensure the safety of ready-to-eat foods • Refrigeration is an environment where Listeria can outcompete mesophilic pathogens Listeriosis and foods Milk • Raw milk is a source of L. monocytogenes • Pasteurization reduces the numbers of Lm • Post-process milk contamination is a concern as Listeria grows faster in pasteurized milk than in raw milk due to fewer competitors Listeriosis and foods Cheeses • L. monocytogenes survives cheese manufacturing and ripening • Temperature hardy, grows in the cold and salt tolerant • Soft cheeses are a risk factor for listeriosis