Role of Microbial Fermentation in Improvement of Barley by Water Treatment.

Abstract

In experiments designed to study the mechanism(s) involved in improving nutritional value of barley by water treatment, it was found that water treated barley taken from the drying oven contained large numbers of bacteria and low numbers of molds, even though the drying temperature was 70[degree] C. The bacterial counts were much larger than for untreated ground barley. Through appropriate techniques a gram-positive rod was isolated from dust in the laboratory and used in subsequent studies. It was found that the nutritional value of sterilized barley inoculated with this organism or with Bacillus subtilis (ATCC 9943) and dried at 70[degree] C was significantly improved. In another experiment a whole culture of the organism isolated in our laboratory was grown in nutrient broth and added to a chick diet containing barley. A significant growth response was obtained but not equal to that obtained by water treatment of barley or by addition of an enzyme concentrate to the feed. These results suggest that the growth improvement obtained by water treatment may be brought about through the action of microorganisms. It was also found that the improved nutritional value of water treated barley was not lowered by autoclaving. This suggests that an irreversible change occurred in the barley and that the improvement by water treatment was not simply formation of enzymes by microorganisms which later acted in the intestinal tract of chicks.