Determination of Aflatoxins Strains and Nutritive Levels Associated With Rastrineobola Argentea in Selected Localities in Kenya

Abstract

Rastrineobola argentea (Omena) is the second important fish catches after Nile Perch in Lake Victoria. Although rich in nutrients, huge postharvest losses are mainly reported during rainy seasons when large catches are made. This could be due to poor handling, processing and packaging practices causing infestation by fungi and subsequent production of aflatoxin under favourable conditions. Despite the economic importance, there are no studies in Kenya to quantify the aflatoxin associated with Rastrineobola argentea and its effects on micronutrient content. This study was therefore undertaken to determine public knowledge, diversity and content of aflatoxins in sun dried Rastrineobola argentea and assess its relationship with the moisture, calcium and iron content. To assess the public knowledge, a survey was carried out around Lake Victoria landing beaches in Kisumu, Migori and Siaya counties and fish markets in Nairobi. A total of 252 samples were collected in dry and wet seasons. The samples were blended and sub-sampled for proximate calcium and iron analysis as well as aflatoxin and moisture content determination. Iron and calcium levels were determined using Atomic Absorption Spectrometry. Total aflatoxin quantification was determined using fluorescence detector in High Performance Liquid Chromatography in reverse phase. Moisture content was quantified using an oven at 130 °C. There was female dominance in fish processing in the study sites. Illiteracy levels was high with majority of the respondents having attained only primary education. Sun drying was the most widely practiced method of fish preservation. There was a wide knowledge gap with 65.59 % unaware of aflatoxins contamination and its health implications. Proximate calcium levels ranged from 1,872.21 to 2,940.90 mg/kg compared to the recommended adult’s daily intake of 1,000 – 1,300 mg. Proximate iron content ranged from 5.62 to 15.64 mg/kg. The total aflatoxin detected in singular samples ranged from 0.44 μg/kg – 4.42 μg/kg signifying Omena aflatoxin contamination. Moisture content was from 10.13 to 14.40 %. Although, total aflatoxin levels were within the accepted limits in Kenya, continued consumption can lead to chronic aflatoxicosis making one vulnerable to liver cancer, neurological area impairment, immunosuppression, and micronutrients deficiencies, stunted growth, child mortality and spontaneous abortion. Hazard analysis of critical control point and good hygiene ought to be operationalized from harvesting through processing and distribution channels of sun dried Rastrineobola argentea to reduce the moisture content as well as the levels of aflatoxin contamination. The national and county Governments of Kenya should educate the general

public on health hazards associated with consumption of contaminated Omena. The findings have contributed to science of analytical chemistry in mitigation of aflatoxin challenges while high calcium and iron content in omena helps in improved diet. The negative correlation of aflatoxin and moisture in Omena merits a further research study.