Changes in Acid-pH Resistance of Food Spoilage and Pathogens Spore-Forming Bacteria in Cameroonian Indigenous Sorghum-Based Acidic Beers before and after Sublethal Thermal Stresses

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James Ronald Bayoï
Roger Djoulde Darman
Francois-Xavier Etoa


Fermented alcoholic beverages play a major role in the socio-cultural lives of people of Northern Cameroon. However, reports of shelf-life and health problems associated with indigenous sorghum-based alcoholic beverages are a major call for concern. This study aimed to highlight the additional effects of sublethal temperatures (no thermal treatment and 10, 45, 50 and 60°C for 45, 90, 180 min) and acidic pH of beers (2.79 and 2.63 for 45, 90, 180 min) on fate of four food spoilage and pathogens spore-forming bacteria. The experiments were carried out on real food products formed by two indigenous sorghum-based alcoholic beverages. Pasteurized traditional beers were significantly efficient on all unstressed bacterial spores after 180 minutes of treatment. In addition, spores of B. megapterium and G. stearothermophilus were more sensitive in white beer pH 2.79 and red beer pH 2.63 respectively. Previous thermal treatments of spores at certain sublethal temperatures have significantly (P=0.05) decreased the effect of both acidic beers on stressed spores. It was noticed that the spores of B. subtilis  stressed at 10°C, G. stearothermophilus (former Bacillus stearothermophilus) spores submitted at 45°C and the spores of B. cereus thermally stressed at 50°C and 60°C for 45, 90, 180 minutes were significantly (P=0.05)  less affected by the white beer at pH 2.79. Whereas, in the red beer at pH 2.63, the spores of B. subtilis sublethally stressed at 10°C and the spores of B. cereus stressed at 45°C, 50°C and 60°C were more acid resistant and very weakly affected by acid pH of the alcoholic beverages. The study delivered some overview on the potential microbial (stability and safety) consequences of the current tendency towards milder cold and heat treatments which are greatly used in the food-grade industry.

Bacillus spores, alcoholic sorghum-based beverages, acid pH, sublethal thermal stresses, food safety.

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How to Cite
Bayoï, J. R., Darman, R. D., & Etoa, F.-X. (2021). Changes in Acid-pH Resistance of Food Spoilage and Pathogens Spore-Forming Bacteria in Cameroonian Indigenous Sorghum-Based Acidic Beers before and after Sublethal Thermal Stresses. Journal of Advances in Microbiology, 20(12), 57-69.
Original Research Article


Attchelouwa CK, Aka-Gbézo S, N’guessan FK, Kouakou CA, Djè MK. Biochemical and microbiological changes during the Ivorian sorghum beer deterioration at different storage temperatures. Beverages. 2017;3(43):1-13. Available:

McGovern PE, Zhang J, Tang J, Zhang Z, Hall GR, Moreau RA, Wang C. Fermented beverages of pre- and proto-historic China. Proc Natl Acad Sci. 2004;101(51):17593–17598. Available:

Hames G. Alcohol in world history. Ed. Routledge, Taylor and Francis Group, 711 Third Avenue, New York, USA; 2014. Available:

Dietler, M. Alcohol: Anthropological/ archaeological perspectives. Annu Rev Anthropol. 2006;35(1):229–249. Available:

Tamang JP, Watanabe K, Holzapfel WH. Review: Diversity of microorganisms in global fermented foods and beverages. Front Microbiol. 2016;7. Available:

Bamba S, Zida A, Sangaré I, Sondo A, Cissé M, Sirima C, Guiguemdé TR, Hennequin C. Characterization of the fungal flora of dolo, a traditional fermented beverage of Burkina Faso, using MALDI-TOF mass spectrometry. World J Microbiol Biotechnol. 2017;33(9). Available:

Minamor AA, Mensah AL, Laryea EN, Afutu E, Tetteh-Quarcoo PB. Microbiological quality of a locally brewed alcoholic beverage (pito) sold in a community within the greater Accra region, Ghana. Preprints; 2017. Available:

Bayoï JR, Darman DR, Etoa F-X. Technologie de fabrication, propriétés physico-chimiques et microbiologiques de la bière «kapsiki blanche » produite dans les monts Mandara au Nord-Cameroun. Afr Sci. 2016;12(6):23-134. French.

Bayoï JR, Djoulde DR, Aboubakar D, Essia-ngang JJ, Etoa F-X. Processing and Quality of “red kapsiki” an Opaque. Bri Biotechnol J. 2015;9(1):1-11. Available:

Lei V, Friis H, Kim FM. Spontaneously fermented millet product as a natural probiotic treatment for diarrhoea in young children: An intervention study in Northern Ghana. Int J Food Microbiol. 2006;110(3): 246-253. Available:

Abdoul-latif FM, Bayili RG, Obame LC, Bassolé IHN, Dicko MH. Comparison of phenolic compounds and antioxidant capacities of traditional sorghum beers with other alcoholic beverages. Afr J Biotechnol. 2012;11(81):14671-14678.

Bayoï JR, Darman DR, Kamga PB, Nyegue M, Olugu VS, Bakary D. et al. Activity of acetic acid on Bacillus stearothermophilus and Bacillus subtilis spores after sublethal heat pretreatments. Int J Innov Sci Res. 2014; 10:570-575.

Bayoï JR, Djoulde, RD, Ehawa FE,Etoa F-X. Influence of sublethal temperatures on some spore-forming and vegetative foodborne bacteria and impact on hygienic quality of the “foléré” (Hibiscus sabdariffa) beverage. Microbiol Res J Int. 2019; 29(6):1-11. Available:

Iciek J, Błaszczyk I, Papiewska A. The effect of organic acid type on thermal inactivation of Geobacillus stearothermophilus spores. J Food Eng. 2008;87(1):16-20. Available:

Dortu C, Thonart P. Les bactériocines des bactéries lactiques: Caractéristiques et intérêts pour la bio-conservation des produits alimentaires. Biotechnol Agron Soc Environ. 2009;13(1):143-154. French.

Zalan Z, Hudacek J, Stetina J, Chumchalova J, Halasz A. Production of organic acids by Lactobacillus strains in three different media. Eur Food Res Technol. 2010;230(3):395-404. Available:

Ganzle GM, Holtzel A, Walter J, Jung G, Hammes PW. Characterization of Reutericyclin produced by Lactobacillus reuteri LTH 2584. Appl Environ Microbiol. 2000;66(10):4325-4333. Available:

Berendsen EM, Zwietering MH, Kuipers OP, Wells-Bennik MH. Two distinct groups within the Bacillus subtilis group display significantly different spore heat resistance properties. Food Microbiol. 2015;45:18-25. Available:

Marshall KM, Nowaczyk II L, Morrissey TR, Loeza V, Halik LA, Skinner GE et al. Effect of sporulation temperature on the resistance of Clostridium botulinum type a spores to thermal and high pressure processing. J Food Protec. 2015;78(1): 156-167. Available: