Shell-life and microbiological quality of lamb meat as effected by high pressure, irradiation and combination treatments

The effect of gamma irradiation (1.0 kGy) and high hydrostatic pressure (220 MPa for 30 min), either alone or in combination on the shelf-life of minced lamb meat stored at 0-3 deg C have been investigated. Untreated control samples initially have total microbial counts of 105 CFU/g, 102 CFU/g of coliforms and 104 CFU/g of Staphylococcus spp. Coliforms are eliminated by all the treatments. Staphylococcus spp. however, are reduced only by 1 log cycle when treated with either irradiation alone or high pressure alone and this flora is a mixture of mannitol fermenting and mannitol non-fermenting species. In samples subjected to the combination treatment Staphylococcus spp. appears only after 3 weeks of storage and all are mannitol non-fermenting. On the basis of microbiological and sensory quality the shelf life of control sample is less than 1 week. All treated meat samples have shelf life of 3 weeks but only combination treated samples are free from potentially pathogenic Staphylococcus spp. The results demonstrate the potential application of low dose irradiation combined with high pressure treatment for shelf-life enhancement and microbial safety of meat and meat products. (author)