Effect of Pasteurized Low Acidic Indigenous Beverages Produced in Northern Cameroon on Germination of Bacillus and Geobacillus Spores Species

Abstract

The present study aimed to investigate the influence of three commercially available traditional acidic beverages on spore germination. “Foléré”, red “té” and white “mpedli” sorghum beers have been produced at the laboratory scale assisted by experimented producers, and pH of samples were adjusted at 2.01, 2.63 and 2.8 respectively, then they were pasteurized. The samples produced were tested on four spore-forming bacteria (Bacillus cereus, Bacillus megapterium, Bacillus subtilis and Geobacillus stearothermophilus) and germination was assessed both on culture plate media and by loss of optical density (OD) methods. The results obtained showed that “foléré” at pH 2.01, and both indigenous sorghum red beer at pH 2.63 and white beer at pH 2.8 were effective on spore germination, and efficacy significantly increase (p < 0.05) with the incubation time. The presence of alcohol in the pasteurized white (2.43 %) and red (4.7 %) sorghum beers has significantly (p < 0.05) improved the anti-germinating activity compared to the non-alcoholic “foléré” beverage. The sensitivity of B. cereus and B. subtilis was positively and significantly correlated (r = 0.880; p < 0.01) likewise the sensitivity of B. megapterium and G. stearothermophilus (r = 0.725; p < 0.05), and the activity of traditional white and red sorghum beers was found to be very significant (p < 0.05) for each couple respectively. The loss of OD showed an inhibitory effect of indigenous beverages germination and exhibited a microcycle on all tested spore-forming bacteria. It was concluded that if the good hygiene and manufacturing practices were applied for production of indigenous beverages, they might easily be used as natural preservatives and for prevention of gastroenteritis induced by germination and outgrowth of spore-forming bacteria like B. cereus.