Reduction of sterigmatocystin biosynthesis and growth of food-borne fungi by lactic acid

Abstract

Corresponding author: Sunčica Kocić-Tanackov, e-mail: suncicat@uns.ac.rs, Tel: +381 14 21 485 3715, Fax: +381 21 450 413 15 16 Running head: Reduction of sterigmatocystin biosynthesis by lactic acid 17 18 Abstract 25 26 2Food contamination by fungi and mycotoxins presents a problem for food safety even today. 27Since lactic acid (LA) has Generally Recognized As Safe (GRAS) status, the aim of this 28 research was to determine its potential in protection of food against mycological and 29 mycotoxicological contamination. In this study, LA showed an inhibitory effect on the growth 30 of food-borne fungi (Penicillium aurantiogriseum K51, Aspergillus parasiticus KB31, 31 Aspergillus versicolor S72, and Aspergillus niger K95) and on biosynthesis of 32 sterigmatocystin (STE). For the antifungal effect of LA on the growth of food-borne fungi, 33 the disc diffusion and microdilution methods were performed. The effect of LA on the STE 34 biosynthesis by A. versicolor was determined using an LC-MS/MS technique. The largest 35 inhibition zone was observed for A. versicolor (inhibition zone of 24±0.35 mm), while there 36 were no inhibition zones for A. niger and A. parasiticus at all tested LA concentrations. The 37 minimal inhibitory concentration (MIC) of LA on fungi ranged from 25.0 mg/mL to 50.0 38 mg/mL, while the minimum fungicidal concentrations (MFCs) ranged from 50.0 mg/mL to 39 100.0 mg/mL. Complete inhibition of STE biosynthesis by A. versicolor was observed at an 40 LA concentration of 50.0 mg/mL. The obtained results showed that LA could be efficient for 41 protection of food against mycological and STE contamination. 42 43