Efficacy of Ozone to Reduce Fungal Spoilage and Aflatoxin Contamination in Peanuts

Peanuts (Arachis hypogea L.) are important substrates for the growth and subsequent aflatoxin production by different members of Aspergillus. The aims of the current study were to identify the toxigenic fungi associated with peanut and to study the effect of ozone gaseous (O3) on fungal spoilage and aflatoxin concentration in peanuts. Peanut samples were collected from three Egyptian governorates i.e. Sharkia, Cairo and Ismailia during winter season of 2007. Peanut samples were exposed to O3 at doses of 20 ppm for 5 min, 40 ppm for 10 min and 50 ppm for 5 min. Total fungal counts were estimated in ozonated and non-ozonated peanuts shells and seeds using tow different media and aflatoxin concentration was determined in the ozone treated and non-treated peanuts. The results indicated that all the shell and seed samples were infected with fungi and the samples from Sharkia were the most infected while contained the highest total fungal counts followed by the samples collected from Cairo governorate. Aspergillus flavus was isolated from all seed samples but did not isolated from peanut shells. Exposure to O3 gaseous was effective to reduce total fungal counts in a dose dependent manner and succeeded to eliminate A. flavus in seed samples. All seed samples were contaminated with aflatoxin and O3 at 40 ppm for 10 min succeeded to degrade aflatoxin in peanut seeds to reach the maximum level set in the Egyptian standards regulation.