Studies on the Effectiveness of Wild and Commercialstrains of Lactic Acid Bacteria Starter Culture during Backsloping for Yoghurt Production

Abstract

Yogurt is one of the traditionally fermented dairy products which are usually prepared with lactic acid bacteria cultures containing Streptococcus thermophilus and Lactobacillus bulgaricus. This starter culture could be prepared in addition to other bacteria as probiotics. Yoghurt has gained widespread consumer acceptance as a healthy diet. Yoghurts products are produced in Nigeria by using the imported starter culture bacteria and has played significant roles in helping dairy farmers convert their short-life, highly perishable fresh milk to fairly more stable products like cheese and yoghurt which are highly nutritious too for both low-and high-income earners. However, there are concerns over the growing food and food-related import dependency in the sub-African countries and Nigeria in particular which have increased during the last few years. The selection of indigenous starter culture strains withthecapacity for backsloping in yoghurt production might reduce importation and improve economy in a way. A foundamental benefit of backsloping is that it reduces the fermentation time while successfully maintaining sensory attributes of the product. The goal of this study was to determine the effects of backsloping fermentation of milk using indigenous and commercial (Exotic) strains of Lactic Acid Bacteria. Yoghurt fermentation was carried out by backsloping method using three commercial (Exotic) formulated cultures of Lactobacillus bulgaricus and Streptococcus thermophillus; ES07, ES32 and ES14 respectively as well aswild (isolated) formulated culture strains; WS11, WS65 and WS13 respectively and were used to produce yoghurt using backsloping method.. The overall sensory attributes of yoghurts produced using exotic compared with indigenous strains showed no significant (p > 0.05) difference in term of acidification and coagulation ability. The pH of fermented products using commercial cultures ranged from 4.53-5.32,  While pH of yoghurts produced using isolated cultures ranged from 4.35 – 4.72, total plate count 2.7 x 107- 2.3 x 108cfu/ml during the 10 hour fermentation times.The overall acceptability were in the decreasing order; WS65>WS11>ES07>WS13>ES14>ES32.. From this order, backloping has equal advantages when both local and commercial starter cultures are used. Therefore, Starter culture formulation using indigenous strains could be further developed genetically for commercial applications because they compete favourably with their exotic counterparts. Hence, the current challenges of importation due to Covid-19 economic reality and foreign exchange will reduce to a minimal if the indigenous strains are utilised.