TY - JOUR
T1 - Effects of temperature, pH, and controlled water activity on inactivation of spores of Bacillus cereus in paprika powder by near-IR radiation
AU - Staack, N.
AU - Ahrné, L.
AU - Borch, E.
AU - Knorr, D.
PY - 2008
Y1 - 2008
N2 - A process to decontaminate paprika powder using variable near-infrared (IR) radiation was tested using a closed sample holder allowing water to be retained in the powder. The reduction in the concentration of Bacillus cereus spores and changes in water activity (aw) and colour were measured during IR heating. High heat flux was applied initially to heat the powder rapidly to the desired temperature, followed by low heat flux to maintain the temperature for a given time. The water activity (aw) value of the powder could be maintained within the bulk of the closed sample, but the surface aw value decreased during heating. Due to carotenoid sensitivity to temperature, surface and overall colour values declined, though remaining acceptable values of medium red and red, respectively. For powder with an aw value of 0.88 heated to 95-100 °C, the load of B. cereus spores was reduced by 4.5 log10 CFU/g within 6 min; the final spore concentration remained approximately 2 log10 CFU/g due to tailing. Reducing pH to 4.0 from 4.5 did not significantly affect the reduction of the B. cereus spore concentration.
AB - A process to decontaminate paprika powder using variable near-infrared (IR) radiation was tested using a closed sample holder allowing water to be retained in the powder. The reduction in the concentration of Bacillus cereus spores and changes in water activity (aw) and colour were measured during IR heating. High heat flux was applied initially to heat the powder rapidly to the desired temperature, followed by low heat flux to maintain the temperature for a given time. The water activity (aw) value of the powder could be maintained within the bulk of the closed sample, but the surface aw value decreased during heating. Due to carotenoid sensitivity to temperature, surface and overall colour values declined, though remaining acceptable values of medium red and red, respectively. For powder with an aw value of 0.88 heated to 95-100 °C, the load of B. cereus spores was reduced by 4.5 log10 CFU/g within 6 min; the final spore concentration remained approximately 2 log10 CFU/g due to tailing. Reducing pH to 4.0 from 4.5 did not significantly affect the reduction of the B. cereus spore concentration.
KW - Bacillus cereus spores
KW - Infrared (IR) radiation
KW - Paprika powder
KW - pH
KW - Water activity
U2 - 10.1016/j.jfoodeng.2008.05.010
DO - 10.1016/j.jfoodeng.2008.05.010
M3 - Journal article
AN - SCOPUS:46049100966
SN - 0260-8774
VL - 89
SP - 319
EP - 324
JO - Journal of Food Engineering
JF - Journal of Food Engineering
IS - 3
ER -