Nutritional and microbiological quality of sun-dried silver cyprinid during storage

Abstract

Silver cyprinid is a cheap, accessible, highly nutritious food that is incorporated diets of infants as a fortified protein source. However, this silver cyprinid is prone to degradation during storage but the effect of storage practices and packages on its nutrient and microbial quality is not known. There was need for to quantify variation in quality of silver cyprinid from different sites and influence of storage practices on nutritional and microbial changes. Methodology: Field surveys were used to collect data about the storage practices at landing sites (n for sites= 4 and n for respondents = 71) and in markets (n for markets= 5 and n for respondents=41). Samples of silver cyprinid obtained from the landing sites (n = 41) and markets (n =30) were analyzed for nutritional quality (crude protein, crude fat, ash, moisture content, free fatty acids, peroxide value, Thiobarbituric acid (TBA) and pH) and microbial safety (total fungal count, total plate count, total coliforms, TMA and TVBN). An 8-week simulated storage experiment of silver cyprinid in open and closed gunny bags was also set up to establish the effect of packaging on stability of nutrition and microbial properties.: Storage was at room temperature of 21.3-27.3o C with most people (60%) storing in closed gunny bags and the rest stored in the open (40%). Majority of the respondents (98%) stored silver cyprinid for less than 3 months. There is was no established official quality criteria followed during handling and storage of silver cyprinid. The average nutrient quality of silver cyprinid was 16.6±5.6%, 8.6±2.4%, 13.5±2.3%, 52.2±5.1%, 18.5±8.7mg/100g, 0.7±1.9 meq/kg, 6.6±2.6 mg KOH/g, 6.4±0.2 for moisture content, crudefat, crude ash, crude protein, iron content, peroxide, acid values and pH, respectively. The microbial quality parameters were 79.3±31.9 µmolMDA/g, 8.4±4.5 mgN/100g, 7.5±7.4 mgN/100g, 6.7±1.3 cfu/g, 3.9±1.2 cfu/g, 4.2±1.0 cfu/g for TBA, TVBN, TMA, TPC, TC, yeasts and moulds respectively. The nutritional and microbial quality of silver cyprinid samples in the markets was lower than that from the landing sites. The nutritional and microbial quality of silver cyprinid obtained from different landing sites varied significantly (p<0.05). The rate of deterioration was lower (most parameters were not significantly different (p>0.05) except for TVBN (p = 0.037)) in closed gunny bags than in open gunny bags. Stored silver cyprinid was generally nutritious though not safe for utilization in baby foods since aflatoxin content of all samples was higher than 0.05ppb which is the maximum allowable limit. It is recommended that silver cyprinid should be stored using closed gunny bags, further research should evaluate the use of hermetic storage to prevent quality deterioration and the possibility for safer silver cyprinid.