Effect of Microwave Treatment on Microbial Contamination of Honeys and on Their Physicochemical and Thermal Properties

MOLINÉ, M.P.; FERNÁNDEZ, N.; MEDICI, S.K.; FASCE, D.; GENDE, L.

Polish Journal of Food and Nutrition Sciences

Prof. dr hab. Henryk Zieliński

Año: 2015 vol. 65 p. 119 - 126

1230-0322

In recent years, microwave heating has become a common method for pasteurization and sterilization of food. Honey is a sweet substance producedby worker honeybees from nectar of fl owers. The major microbial contaminants include moulds and yeasts, as well as the spore-forming bacteria,being their counts indicative of honeys? commercial quality and safety. Paenibacillus larvae is also of interest since it causes American foulbrood(AFB) in honeybee larvae. The main quality factors that are used in the honey international trade are moisture, hydroxymethylfurfural content (HMF),and enzymatic indices. Moreover, honey exhibits several thermal events, the most important being the glass transition temperature (Tg). The aim of thiswork was to evaluate microwave effect (800 watts during 45 and 90 seconds) on microbial content in particular over P. larvae spores retained in honey,and on physicochemical and thermal properties. Microwave promoted a decrease of microbial count with time of exposure, including P. larvae. Moisturecontent diminished after treatment, while Tg increased linearly, and acidity decremented in the majority of cases. Honeys darkened and HMFexceeded the permissible value. Diastase and glucose-oxidase enzymes were totally inactivated by microwave treatment.