Me. Parish, HIGH-PRESSURE INACTIVATION OF SACCHAROMYCES-CEREVISIAE, ENDOGENOUS MICROFLORA AND PECTINMETHYLESTERASE IN ORANGE JUICE, Journal of food safety, 18(1), 1998, pp. 57-65
Decimal reduction times (D-values) for Saccharomyces cerevisiae ascosp
ores inoculated into pasteurized orange juice ranged from 4 to 76 s at
pressures between 500 and 350 MPa. At the same pressures, D-values of
S. cerevisiae vegetative cells ranged from 1 to 38 s while those for
the native microflora in nonpasteurized Hamlin orange juice were betwe
en 3 and 74 s. Corresponding z-values were 123, 106 and 103 MPa for as
cospores, vegetative cells and native microflora, respectively. Native
microorganisms that survived high pressure treatments included yeasts
, gram-positive and gram-negative bacilli Pectinmethylesterase activit
y in nonpasteurized Hamlin orange juice was reduced to 5% of initial a
ctivity after 30 s at 900 MPa.