MICROBIOLOGICAL QUALITY OF MECHANICALLY RECOVERED POULTRY MEAT TREATED WITH HIGH HYDROSTATIC-PRESSURE AND NISIN

The combined effect of high hydrostatic pressure processing, addition of nisin and acidification on aerobic mesophilic and psychrotrophic ba cterial populations of mechanically recovered poultry meat (MRPM) kept under refrigeration (2 degrees C) was evaluated 1, 15 and 30 days aft er pressurization. Nisin (0, 12.5, 100 and 200 ppm) and glucono-delfa- lactone (GdL, 0 and 1%) were added to MRPM. Vacuum-packaged samples we re treated at 350 or 450 MPa and 2 degrees C for 15 min using both con tinuous pressurization and three-cycle oscillatory pressurization for 5 min per cycle. in some samples a reduction of mesophile counts betwe en 3.44 and 5.38 log cfu g(-1) was found. Psychrotrophes seemed to be more sensitive,. in samples with 100 ppm of nisin and GdL treated at 4 50 MPa with cycles they were reduced to undetectable levels (a lethali ty of approximately 7.5 log units). Cycle pressurization showed slight ly better results than continuous pressurization. The combination of 3 50 MPa, 100 ppm of nisin and 1% of GdL was enough to extend the shelf life of MRPM during the 30 day chilled storage. (C) 1998 Academic Pres s.