Preliminary studies on the in situ prevention of food spoilage fungi using antifungal Lactic acid bacteria

Food loss is a major threat in the world and one-third of the food produced for human consumption are wasted. Many fungal species cause loss of food/raw materials like grains, fruits and vegetables throughout the world. Chemical preservatives and fungicides when used in food have negative impacts on health and the environment. Biopreservatives such as lactic acid bacteria (LAB) are effective, safe, biodegradable and have additional health benefits. The focus of this research is to survey the occurrence of native lactic acid bacteria with antifungal activity in various food sources and to obtain a potential lactic acid bacterial isolate for strategic application to control fungal pathogen in food products. In the present study, the population of lactic acid bacteria were about 104 to 105 cells in all food samples. Sixty isolates of lactic acid bacteria were obtained from samples collected. Of these, 21 exhibited inhibition towards the growth of Fusarium oxysporum and 13 isolates towards A. flavus. Ten of the total isolates exhibited inhibition towards both the test fungi. Based on potential of antifungal activity in the dual plate technique, six isolates were selected and subjected to fungal growth inhibition analysis using microplate. Of these six isolates, the isolate LABT3 showed the highest inhibition percentage (%) against both the target fungi. The isolate was tested for its growth and maximum growth was noted at 48 h and pH at this period was 5.16.