Effect of high pressure processing on refrigerated shelf-life of sliced smoked cooked ham

The objective of this study is to evaluate the microbiological, physico-chemical and sensory properties of sliced vacuum-packaged smoked cooked ham after high pressure treatment and determine if high pressure processing (HPP) is a valid preservation method to reduce the growth of spoilage microorganisms without modification of its quality properties. Slices of cooked vacuum-packaged ham were submitted to high pressure treatments at 400 and 600 MPa for 10 min at 12℃ and then stored at 4℃. Counts of aerobic mesophiles, lactic acid bacteria, enterobacteria and psychrotrophs were determined 0, 2, 4, 6, 8, 10, 12, 14 weeks after treatment, respectively. In addition, TBA, colour, Aw as well as sensory analysis were performed at the same time on the treated and non-treated (NT) slices. It was found that HPP caused a degree of microbiological inactivation, which increased with pressure level. The NT samples proved to be spoiled by lactic acid bacteria (around 106 cfu/g) after 2 weeks of refrigerated storage, while the shelf-life of those submitted to HPP of 400 and 600 MPa could prolonged to 8 and 10 weeks, respectively. High pressure treatment inactivated lactic acid bacteria at a rather low level (＜104 cfu/g) for a long period, Enterobacteriaceae were detected below the detection limit during the whole storage period (102 cfu/g), and the initial competition abilities of Psychrotrophs and Enterobacteriaceae were lost after HPP. the pH values of the sliced cooked hams were significantly increased after HPP. The firmness of pressurized hams was decreased a little, no other changes were found in sensory parameters after HPP and during refrigerated storage. The application of HPP on meat products after final packaging is an efficient method for delaying the growth of spoilage microorganisms in sliced smoked cooked ham and extending the shelf life of the pasteurized cooked meat products.