Recent studies indicated the inhibitory effects of lactic acid bacteria (LAB) strains isolated from different origins on both fungal growth and aflatoxin production. This study aimed to investigate the inhibitory effect of Lactobacillus plantarum and L. delbrueckii subsp. Lactis on Aspergillus parasiticus ATCC15517 growth. Quantification of aflatoxin was performed using high‐performance liquid chromatography technique. Quantitative changes in the expression of the aflR gene were analyzed by measuring the cognate aflR mRNA level with quantitative real‐time reverse‐transcription polymerase chain reaction. Our results demonstrated the inhibitory effect of LAB on A. parasiticus growth at 2 × 103 cfu/ml of L. plantarum and L. delbrueckii subsp. Lactis. Aflatoxin G2 production was significantly inhibited to lower than level of detection. The level of aflR gene expression was considerably decreased after the exposure of fungal cells with used LABs. Assessment of the used LABs on A. parasiticus revealed antifungal properties and effective ability to decrease aflatoxin production. Practical applications Fungi spoilage is widespread among different types of food that may result in huge amounts of waste and economical lost. In addition, side effects raised by using chemical additives as preservative, are a serious source of health concern. Therefore, natural agents such as lactic acid bacteria which are also commonly used as probiotics in recent years, could play a good role as inhibitors of fungal growth as well as mycotoxin production both in food and feed. Different media like dairy foods and so on, can be formulated with Lactobacillus plantarum and L. delbrueckii subsp. Lactis, to prevent Aspergillus parasiticus growth and mycotoxin excretion. LAB can be added to processed food during inoculation step and even for protection, they can be capsulated with edible materials to improve their efficiency.

Aspergillus parasiticus is one of the most common fungi able to produce aflatoxins, which are naturally occurring carcinogenic substances. This study evaluated the effects of the safe yeast, Kluyveromyces lactis, on fungal growth, aflatoxin production and expression of aflR gene in A. parasiticus. Antifungal susceptibility was evaluated by exposing A. parasiticus to different amounts of K. lactis, and aflatoxin production was measured using high-performance liquid chromatography. Expression of the aflR gene was determined by measuring the cognate aflR mRNA level by quantitative real-time reverse-transcription polymerase chain reaction assay. The growth of A. parasiticus was inhibited by 7 days of incubation at 30°C with a minimum population of 1.5 × 105 CFU/ml of K. lactis, which also suppressed expression of the A. parasiticus aflR gene, reducing the total production of aflatoxins by 97.9% and aflatoxins B1, B2, G1 and G2 by 97.8, 98.6, 98 and 94%, respectively. Accordingly, K. lactis could be considered as a potential biocontrol agent against toxigenic molds in food and animal feed.

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