Mycological quality of masmin and mycotoxigenicity

Abstract- Masmin is a traditional culinary product of Lakshadweep Islands that is prepared by cooking in sea water followed by alternate drying and smoking till the moisture content is reduced below 10%. Growth of certain types of fungi is known to enhance the acceptability of the product due to the typical flavor imparted but growth of toxigenic fungi during moulding can lead to food
poisoning.

The physico-chemical and microbiological parameters and the mycological quality of commercially produced masmin of Lakshadweeep Islands was assessed by collecting samples every month for a period of three months from two local production units each of three islands, viz., Agathi, Minicoy and Andrott.

Moisture content of masmin samples were found ranging between 7.68 and 16.83%, and water activity between 0.671 and 0.778. NaCl content was in the range 2.89- 5.42% and pH in the range 5.95-6.45. TVBN content of masmin was ranged from 30.02 to 44.83 mg%.

The total plate count was observed to be highest in samples from Andrott (1.5815x105 cfu/g) and lowest in those from Agathi (8.91 x104unit cfu /g) with average mean of 1.247 x105 (cfu/ g). The total fungal count of the product varied between 1.17x104 and 1.22x105 cfu/ g with an average of 5.20x104 cfu/ g. TFC was found highest for Agathi and lowest for Andrott. Both TPC and TFC showed an increasing trend from the month of May to July possibly on account of the onset of monsoon.

Mycoflora of masmin was dominated by the genus, Aspergillus, constituting about 60% of the total fungal flora, followed by Pencillium (20%), Fusarium (6.6%) Eurotium (3.3%), Candida, Rhizopus, Acladium and Cladosporium (1.6 % each). The mycoflora of masmin samples from each island showed more or less similar pattern with Aspergillus species dominating.

Toxigenic potential of the isolated fungi were analysed by cultural methods viz., cyclodextrin-enhanced fluorescence test, ammonium hydroxide vapour test and found that 33% (20 isolates) of them were capable of producing mycotoxins. Among them 11 were found highly positive and the remaining slightly positive based on the intensity of fluorescence. Two isolates of Aspergillus flavus from Agathi Island and one each from Andrott and Minicoy showed intense blue fluorescence under UV light (365nm) indicating aflatoxin production. One isolate from Andrott and two each from Minicoy and Agathi showed intense yellowish green fluorescence indicative of citrinin toxin production. One isolate each of A. niger from all the three islands showed blue fluorescence under UV light ( 365) indicative of ochratoxin production. Three isolates from Andrott, two from Minicoy and one from Agathi showed slight fluorescence under UV indicating their low toxin production capability.

TLC analysis of extracts of various toxigenic fungi showed fluorescent bands under UV light indicating that the isolates were capable of producing different toxins.

In order to quantify aflatoxin (B1 and B2) content of the masmin samples HPLC analysis of masmin extracts was carried out. However none of the products were found to contain measurable amounts of aflatoxin B1or aflatoxin B2. Hence it may be interpreted that the masmin samples collected from the Lakshadweep Islands, although were contaminated with toxigenic fungi, were safe for consumption. However, precautions should be taken about marketing of only safe products as variations in processing or storage conditions may encourage excessive growth of toxigenic fungi and toxin production.