Thermal resistance characteristics of PA 3679 in the temperature range of 110-121 degrees C as affected by pH, type of acidulant and substrate.
The influence of mushroom extract, acidification and type of acidulant (citric acid or glucono-delta-lactone) on the thermal resistance of PA 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 (acidified mushroom extract). Spores were less heat resistant in the non-acidified mushroom extract than in phosphate buffer. However, acidification of the extract had an effect on D values which was dependent on the specific pH. At pH 6.22, D values were higher than those in non-acidified extract, for both type of acidulants, but the difference between D values in both substrates was affected by temperature, the higher the temperature, the less the difference. Acidification at other pH levels did not significantly affect D values obtained, neither did the type of acidulant. The z value ranged from 9.79 to 12.09 degrees C for citric acid and from 8.18 to 10.18 degrees C for glucono-delta-lactone. When pH was decreased the z value increased for both acidulants.
Ocio
M J
MJ
Instituto de Agroquímica y Technología de Alimentos, Valencia, Spain.
Sánchez
T
T
Fernandez
P S
PS
Rodrigo
M
M
Martínez
A
A
D001487:Basidiomycota; D002951:Citrates; D019343:Citric Acid; D003013:Clostridium / Q000254:growth & development*; D003470:Culture Media; D005516:Food Microbiology; D005524:Food Technology; D005942:Gluconates; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D007783:Lactones; D013171:Spores, Bacterial / Q000254:growth & development
D002951:Citrates; D003470:Culture Media; D005942:Gluconates; D007783:Lactones; D019343:Citric Acid; C010730:beta-glucono-1,5-lactone