MSc

The study entitled “Investigation on the mycoflora of nutmeg in storage and the associated mycotoxin.” was carried out in the Department of Plant Pathology, College of Agriculture, Vellayani during the year 2012-2014 with the objective to isolate the fungi associated with nutmeg and mace in storage, detection and estimation of mycotoxin and methods to minimize fungal infection.
Survey was conducted in Kozhikode and Thrissur districts during February- March and June-July 2013 and collected 40 samples each of nutmeg and mace. Quantitative estimation of the fungal population revealed that samples of nutmeg and mace collected during June-July had the highest population. Positive and significant correlation was obtained between moisture content of the sample and fungal population. Qualitative estimation of the fungi indicated the presence of 13 different fungi, among which Aspergillus flavus and A. niger, were the predominant ones. The study on the detection of mycotoxin revealed that aflatoxin (805-964 ppb) was present in three samples of nutmeg and mace.
Nine isolates of A. flavus and12 isolates of A. niger were tested for their ability to elaborate aflatoxin in culture and substrate, among which five isolates of A. flavus and seven of A. niger obtained from nutmeg was aflatoxigenic in culture media. Similarly two of the four isolates of A. flavus and all the five of A. niger from mace produced aflatoxin in culture.
Studies on the production of aflatoxin in the substrate indicated that five A. flavus and seven A. niger isolates elaborated aflatoxin in nutmeg, whereas, two A. flavus and five A. niger isolates produced aflatoxin in mace.
A. ochraceous isolates were tested for their ability to produce ochratoxin in culture and in substrate and found that all the five isolates produced ochratoxin A, 970.43 - 1835.95 ppb in culture and 6.01 - 212.33 ppb in nutmeg.
Studies on the methods to minimize fungal infection in nutmeg and mace revealed that among the treatments: essential oil, leaf powder/plant extracts and packing materials, plastic bag was found to be the cheapest, had comparatively lower moisture content and lowest fungal population; whereas nutmeg treated with garlic extract (10 per cent) and mace with onion extract (10 per cent) and stored in polypropylene bag recorded higher fungal population throughout the period of observation (12 weeks).
The results of the study clearly indicated that nutmeg and mace collected during June – July had the highest population of fungi with positive and significant correlation on the sample moisture. Aspergillus flavus and A. niger occurred in the highest frequency and aflatoxin B1 was the predominant mycotoxin. Also, storing in the plastic bag was the cheapest method to reduce fungal spoilage and elaboration of mycotoxin.