Antifungal activities of lactic acid bacteria and yeast isolated from various types of Tempe

Abstract

Mycotoxin-producing fungi are harmful contaminants in food and feed products. Lactic acid bacteria (LAB) and yeast groups are known to produce antifungals. Indonesia is known as a Tempe-producing country, an important functional fermented food. Soybean Tempe has been commonly known and well-studied, while other types of Tempe such as Tempe Gembus, Tempe Koro, Tempe Lamtoro and Oncom have not been well studied. This study aimed to determine LAB and yeast population in various types of Tempe and to select antifungal activity against mycotoxin-producing fungi. Research methods included total aflatoxin analysis in Tempe products, enumeration and isolation of LAB and yeast, and antifungal assay. The results showed that the total aflatoxins in all Tempe products were 1.99 - 3.84 ppb and it was qualified as food for consumption. The total LABs were 7.16 - 8.25 log10 cfu/g while the total yeast was 4.48 - 7.38 log10 cfu/gram. The highest antifungal activities in mycotoxin-producing fungi such as Aspergillus parasiticus and Penicillium citrinum, shown by LAB G1 isolates which were identified as Lactobacillus sp. and yeast G6K1 and G6K2 which were identified as Saccharomyces spp. All the selected isolates were isolated from Tempe Gembus. The clear zone diameter of antifungals was 15-20 mm and 3.5 mm respectively for LAB G1 and G6K1-G6K2. These selected LAB and yeast had the potential to be used as natural bio-preservatives in functional food products to prevent the growth of mycotoxin-producing fungi.