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.