Mj. Ocio et al., THERMAL-RESISTANCE CHARACTERISTICS OF PA-3679 IN THE TEMPERATURE-RANGE OF 110-121-DEGREES-C AS AFFECTED BY PH, TYPE OF ACIDULANT AND SUBSTRATE, International journal of food microbiology, 22(4), 1994, pp. 239-247
The influence of mushroom extract, acidification and type of acidulant
(citric acid or glucono-delta-lactone) on the thermal resistance of P
A 3679 spores has been studied. The pH values were 7 (phosphate buffer
), 6.7 (non acidified mushroom extract), 6.22, 5.34 and 4.65 (acidifie
d mushroom extract). Spores were less heat resistant in the non-acidif
ied mushroom extract than in phosphate buffer. However, acidification
of the extract had an effect on D values which was dependent on the sp
ecific pH. At pH 6.22, D values were higher than those in non-acidifie
d extract, for both type of acidulants, but the difference between D v
alues in both substrates was affected by temperature, the higher the t
emperature, the less the difference. Acidification at other pH levels
did not significantly affect D values obtained, neither did the type o
f acidulant. The z value ranged from 9.79 to 12.09-degrees-C for citri
c acid and from 8.18 to 10.18-degrees-C for glucono-delta-lactone. Whe
n pH was decreased the z value increased for both acidulants.