Processing of fish offal waste through fermentation utilizing whey as inoculum

Abstract

Background: Lactic acid fermentation is a strong tool to convert biodegradable wastes into food ingredients for animal husbandry. Experiments were made to evaluate if lactic acid bacteria of whey, a by-product of dairy industry, could be exploited to ferment fish offal waste (FOW) and to compare the effectiveness of whey as fermentation inoculum with that of a pure culture of Lactobacillus acidophilus. Results: Although fermentation of FOW by whey required 5 days to complete in contrast to 3 days required for fermentation by L. acidophilus, removal of hazardous microorganisms like Staphylococcus, Clostridium and coliform bacteria was better in the whey-fermented fish offal (WFFO) than that of L. acidophilus-fermented fish offal (LAFFO). Protein and lipid contents of the wastes were almost completely recovered in both the fermented products, with WFFO showing a higher amount of free amino acid than the LAFFO. Both the fermented products were stable against the growth of mould and yeast. Conclusion: It is concluded that whey is a viable and easily available inoculum to ferment FOW and convert it to a microbiologically safe and nutrient-rich end product suitable for use as feed supplement in animal feed formulation.