Control of Yersinia enterocolitica in raw pork and pork products by γ-irradiation

γ-Radiation response of Y. enterocolitica 5692 and 152 was studied at 0°C and at −40°C in phosphate buffer (pH 7.00) as well as in 10% raw meat/salami homogenate. The strains investigated did not differ in their response and were found to be sensitive to γ-radiation but exhibited a tailing phenomenon in the survival curve. The D10 in homogenate was 0.25 kGy at 0°C. This response was not affected at −40°C. Storage studies of packs, inoculated artificially with heavy inoculum of Y. enterocolitica (106 cfu/g) showed that while samples of salami and cooked ham could be decontaminated at doses of 4 and 3 kGy respectively; cells could not be eliminated from raw pork meat even at the higher dose of 6 kGy. The role of different treatments given prior to irradiation for revival of Y. enterocolitica after irradiation storage was also studied. The dose of 1 kGy at −40°C was efficient in eradicating low numbers (<103) of naturally occuring Y. enterocolitica from raw pork meat without any revival during storage at refrigeration temperature.