TY - JOUR

T1 - Infrared Decontamination of Oregano

T2 - Effects on Bacillus cereus Spores, Water Activity, Color, and Volatile Compounds

AU - Eliasson, Lovisa

AU - Libander, Patrik

AU - Lövenklev, Maria

AU - Isaksson, Sven

AU - Ahrné, Lilia

PY - 2014/1/1

Y1 - 2014/1/1

N2 - Infrared (IR) heating, a novel technology for decontaminating oregano, was evaluated by investigating the reduction of inoculated Bacillus cereus spores and the effect on water activity (aw), color, and headspace volatile compounds after exposure to IR treatment. Conditioned oregano (aw 0.88) was IR-treated in a closed heating unit at 90 and 100 °C for holding times of 2 and 10 min, respectively. The most successful reduction in B. cereus spore numbers (5.6 log units) was achieved after a holding time of 10 min at 90 °C, while treatment at 100 °C for the same time resulted in a lower reduction efficiency (4.7 log units). The lower reduction at 100 °C was probably due to a reduced aw (aw 0.76) during IR treatment or possibly to the alteration or loss of volatile compounds possessing antimicrobial properties. The green color of oregano was only slightly affected, while the composition of volatile compounds was clearly altered by IR heating. However, two of the key aroma compounds, carvacrol and thymol, were only slightly affected, compared to the effect on the other studied compounds, indicating that the typical oregano aroma can likely be preserved. In conclusion, IR heating shows potential for the successful decontamination of oregano without severe alteration of its color or the key aroma compounds, carvacrol and thymol. Practical Application: This study investigated the potential of infrared heating as a technology for decontaminating oregano. The study outcome contributes to the development of new decontamination solutions to improve the sensory and microbial quality of herbs and spices.

AB - Infrared (IR) heating, a novel technology for decontaminating oregano, was evaluated by investigating the reduction of inoculated Bacillus cereus spores and the effect on water activity (aw), color, and headspace volatile compounds after exposure to IR treatment. Conditioned oregano (aw 0.88) was IR-treated in a closed heating unit at 90 and 100 °C for holding times of 2 and 10 min, respectively. The most successful reduction in B. cereus spore numbers (5.6 log units) was achieved after a holding time of 10 min at 90 °C, while treatment at 100 °C for the same time resulted in a lower reduction efficiency (4.7 log units). The lower reduction at 100 °C was probably due to a reduced aw (aw 0.76) during IR treatment or possibly to the alteration or loss of volatile compounds possessing antimicrobial properties. The green color of oregano was only slightly affected, while the composition of volatile compounds was clearly altered by IR heating. However, two of the key aroma compounds, carvacrol and thymol, were only slightly affected, compared to the effect on the other studied compounds, indicating that the typical oregano aroma can likely be preserved. In conclusion, IR heating shows potential for the successful decontamination of oregano without severe alteration of its color or the key aroma compounds, carvacrol and thymol. Practical Application: This study investigated the potential of infrared heating as a technology for decontaminating oregano. The study outcome contributes to the development of new decontamination solutions to improve the sensory and microbial quality of herbs and spices.

KW - Bacillus cereus spores

KW - Color

KW - Infrared heating

KW - Oregano

KW - Volatile compounds

U2 - 10.1111/1750-3841.12694

DO - 10.1111/1750-3841.12694

M3 - Journal article

C2 - 25393824

AN - SCOPUS:84919371930

VL - 79

SP - E2447-E2455

JO - Journal of Food Science

JF - Journal of Food Science

SN - 0022-1147

IS - 12

ER -