Microbiological Assessment of Wheat and Buckwheat Sprouting Process

Abstract

Introduction. Sprouted grain can cause food poisoning, since inappropriate conditions can promote the growth of pathogenic microorganisms on the grain surface. As a result, products of long-term storage use thermally-treated sprouted grain, the parameters of which depend on the initial bacteria content. There are different ways to reduce bacterial contamination of sprouted grain, each of which has its own advantages and disadvantages. Natural substances with antimicrobial properties, such as medicinal herbs, can serve as decontaminators. However, no scientific research has been performed so far to determine the exact temperature of grain sprouting to minimize its microbiological contamination. The research objective was to investigate the effect of antimicrobial agents and sprouting conditions on the microflora of wheat and buckwheat grain. Study objects and methods. The study featured wheat grain and green buckwheat grain. A set of experiments was performed to define the effect of antimicrobial agents and sprouting conditions on the quantity of mesophilic aerobic and facultative anaerobic microorganisms (QMAFAnM), molds, and yeasts. During sprouting at 10–30°C for 90 h, the grain was irrigated with distilled water, potassium permanganate solution (KMnO4), calendula infusion, and celandine i nfusion. QMAFAnM and the count of molds and yeasts were determined by standard methods; the qualitative analysis of the microflora was based on their morphological and cultural characteristics. Results and discussion. Microflora development during sprouting of wheat and buckwheat grains was controlled by selecting appropriate conditions and grain treatment methods. The herbal infusions for sprouting reduced the total microbial insemination of grain during sprouting by 52–68%; the calendula infusion reduced the contamination with molds by 47–51%, yeasts – by 100%. Conclusion. The research revealed the total microbial count and the count of mold and yeast colonies in dry sprouted grain. The optimal temperature of sprouting wheat and buckwheat was 20 ± 2°C in the infusion of medicinal herbs: it minimized the microflora of sprouted grain and reduced the sprouting time to 46 h. Calendula infusion could be recommended for commercial use in order reduce the microbiological contamination of sprouted grain. The initial microbial population of the product was found to affect the mode of heat treatment in long-term storage products.