ULTRA-HIGH PRESSURE PASTEURIZATION OF FRESH CUT PINEAPPLE

Ultra-high pressure (200, 270 and 340 MPa), temperature (similar to 4, 21 and 38 degrees C), and time (5, 15, 40 and 60 min) combinations we re evaluated as a means to extend the shelf-life of fresh cut pineappl e chunks. Cut pineapple obtained from an industrial processor was pack ed in heat-sealed polyethylene pouches. Triplicate samples were temper ature adjusted and treated in an Autoclave Engineers IP2-22-60 isostat ic press. Surviving bacteria and total yeast and mold counts were dete rmined using plate count agar (PCA) and acidified potato dextrose agar (PDA), respectively. At the highest pressure (340 MPa) and 15 min, de cimal reductions measured by growth on PCA were 3.0 (similar to 4 degr ees C), 3.1 (21 degrees C) and > 2.5 (38 degrees C). Pressure treated pineapple pieces had PCA counts < 50 colony forming units (CFU)/g. At 270 MPa and 15 min, greater than two decimal reductions were observed only at 38 degrees C. Exposure to pressures of 200 MPa resulted in abo ut one decimal reduction in PCA counts for all temperature and time co mbinations tested. PDA counts followed a similar behavior far all pres sure treatments.