Assessment of Microbiological Quality and Safety during the Processing of Traditional Beers made from Sorghum in the “Mandara” Mountains of the Far-North Region of Cameroon

Abstract

Indigenous beers are very popular and widely consumed by people from northern Cameroon because of its low cost. Despite their appeal, microbial quality of these beverages remains a serious call for concern. This work was aimed to investigate microbial changes and hazards of contamination during the processing of two special sorghum beers brewed in northern Cameroon. Producers were observed during the production and samples were collected at different stages for analysis of microbiological parameters such as total count, fungi, spore-forming bacteria, Coliforms and E. coli using referenced methods. Total count ranged from 13.5 x 103 to 195 x 103 CFU/mL and 0.16 x 103 to 660 x 103 CFU/mL; fungi from 0.26 x 103 to 22 x 103 CFU/mL and 0.22 x 103 to 85 x 103 CFU/mL; E. coli from 0.69 x 102 to 13.6 x 102 CFU/mL and 0.65 x 102 to 3.8 x 102 CFU/mL during the production of the red “té” and white “mepdli” beers, respectively. Spore-forming bacteria and Coliforms (total and fecal) were detected in all the collected samples. Bacterial spores were also enumerated in red (38 x 103 CFU/g) and white (62.5 x 103 CFU/g) sorghum grains used as the main raw materials for the production of “té” and “mpedli” beers. The results suggest that the processing of both turbid beers using the traditional method are exposed to microbial contamination. Increase of microbial loads after soaking, adding of the supernatant (red beer only) and malted flour (white beer only) after the heating step means that control measures are needed to prevent contamination after these sensitive stages. Proper handling of raw materials, adequate implementation of heating and fermentation were found as effective critical control points. Training of producers on the hazards analysis and good manufacturing and hygiene practices have been suggested as strategies to improve the safety of indigenous beers.

Physicochemical and microbiological changes during two-stage fermentation production of umqombothi

“…The addition of sorghum malt and fermented beer powder as inoculum, before the second fermentation stage (BSF), increased the product's total flora. Previously, LAB in the production of opaque sorghum beverages showed the same trend [ 35 ]. This category of microorganisms, according to Ref.…”

“…The U3 sample had significantly ( p < 5.36) higher LAB value than U2 and U3 respectively. During cooking (BSF), starch is converted to fermentable sugars, amino acids, and vitamins, which aids in the development of LAB and yeast to produce flavour, and fragrance, and preserve the Umqombothi beverage sensory quality profile [ 2 , 35 ]. The addition of sorghum malt and fermented beer powder as inoculum, before the second fermentation stage (BSF), increased the product's total flora.…”

“…Total coliforms were significantly ( p < 0.00) non-detected at BSF, ASF and FP sampling stages for U1, U2 and U3 respectively. These findings demonstrated that certain stages of heating and fermenting have a critical role in the reduction of coliform bacteria during the production process [ 35 ].…”

A Validated Liquid–Liquid Extraction Method for the Quantitative Analysis of Ethanol in the Different Types of Home-Brewed Alcoholic Beverages of Botswana Using Gas Chromatography Flame Ionization Detector

“…Some households generate enough income from the sale of these beverages to pay for their children's education, put food on the table and meet all the family’s basic needs [ 15 – 17 ]. There has been growing concerns about the hygienic handling of raw materials, production procedures and qualities of the final products including the rise in alcoholism, regarding home brewed alcoholic beverages in African [ 18 , 19 ]. Considerable evidence demonstrates that some beverages are contaminated with bacteria and also contain harmful impurities and adulterants [ 20 , 21 ].…”