High-pressure processing applied to cooked sausages: bacterial populations during chilled storage

Vacuum-packaged cooked sausages were pressurized at 500 MPa for 5 or 15 min at mild temperature (65 degrees C) and later stored at 2 and 8 degrees C for 18 weeks. Counts of aerobic mesophiles and psychrotrophs, lactic acid bacteria, enterobacteria, Baird-Parker microbiota, and Listeria spp. were determined 1 day and 3, 6, 9, 12, 15, and 18 weeks after treatment and compared with those of cooked sausages treated at 80 to 85 degrees C for 40 min. Pressurization generated reductions of about 4 log CFU/g in psychrotrophs and lactic acid bacteria. Enterobacteria and Listeria proved the most pressure sensitive; insignificant or no growth was detected throughout the study. Heat treatment inactivated psychrotrophs and enterobacteria similarly to pressure treatment. Listeria monocytogenes and enterotoxigenic Staphylococcus aureus were not found in treated samples. In general, there was no significant difference in counts of any bacterial populations either among treatments or between storage temperatures. High-pressure processing at mild temperature is an effective preservation method that can replace heat pasteurization applied to some cooked meat and poultry products after packaging.