Delaying the spoilage of fresh and processed meats

Abstract

<p>Various anti-microbial treatments were studied with respect to their use for the shelf-life extension of meat and meat products. The treatments studied were bacteriocins (pediocin AcH and nisin), organic acids, immobilization, ion chelators, high pressure and irradiation. These were then compared using statistical analysis so as to identify treatment effects on the dynamics of growth of the spoilage bacteria. The experiments focused especially on exploiting the potential of pediocin AcH for this purpose;A scale-up method was developed for the purification of pediocin from 50 liters of culture;Pediocin was seen to act in combination with lactic acid on Listeria monocytogenes cells both in broth and meat systems. This combined action was adversely affected by increased salt levels. Meat microflora that survived pediocin application were identified to be primarily grain-negative spoilage organisms like Pseudomonas spp., Acinetobacter spp and some lactic acid bacteria (LAB), and Bacillus spp;The bacteriocin activity persisted in sterile raw ground meat for up to 4 d at 25°C, for 15 d at 7°C, and more than 6 months in frozen samples, and in cooked meat, 6 d when stored at 25°C and for more than 3 months at 4°C. The bacteriocin also remained unaffected by irradiation up to doses of 7.0 kGy and high hydrostatic pressure of up to 100 kpsi;Finally, a treatment combining bacteriocins, ion-chelators, detergent, acetic acid, and high pressure successfully extended the shelf-life of raw meat for more than 15 days and cooked meat for more than 20 days at 15°C. Statistical modeling using non-linear regression was used to identify treatment effects on spoilage populations.</p>