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Infrared Decontamination of Oregano: Effects on Bacillus cereus Spores, Water Activity, Color, and Volatile Compounds
Author(s) -
Eliasson Lovisa,
Libander Patrik,
Lövenklev Maria,
Isaksson Sven,
Ahrné Lilia
Publication year - 2014
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/1750-3841.12694
Subject(s) - carvacrol , thymol , chemistry , bacillus cereus , aroma , food science , human decontamination , spore , cereus , antimicrobial , bacteria , essential oil , botany , organic chemistry , biology , physics , nuclear physics , genetics
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 ( a w ), color, and headspace volatile compounds after exposure to IR treatment. Conditioned oregano ( a w 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 a w ( a w 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.