Influence of Sublethal Temperatures on Some Spore-forming and Vegetative Foodborne Bacteria and Impact on Hygienic Quality of the “Foléré” (Hibiscus sabdariffa) Beverage

Abstract

Aims: “Foléré” beverage is a refreshing locally made drink much appreciated by the populations of the hottest parts of Cameroon. This paper aims at investigating microbial contamination of “Foléré” beverage and highlights impact of the sublethal temperatures on the hygienic quality the beverage.
 Study Design: Design used for describing physicochemical and microbial profile is a random sampling and for impact of sublethal temperature on hygienic quality, we used food matrix simulations.
 Place and Duration of Study: Samples: Local markets, between August 2018 and June 2019.
 Methodology: The sample pH and soluble solids content were recorded using portables devices. Microbial analysis focused on total aerobic mesophilic bacteria, Escherichia coli, and spore-forming bacteria were determined according to accredited culture methods. Acidic “Foléré” beverage produced by an artisanal processing was sterilized and inoculated by Bacillus cereus T spores and Escherichia coli ATCC 25922 cells thermally stressed by pre-incubation at 10°C, 45°C, 50°C or 60°C for 45 min, 90 min and 180 min. The recovery method was used to determine acid pH resistance of both bacteria before and after sublethal thermal processing.
 Results: “Foléré” beverage is of poor hygienic quality according to standards, despite its very low pH (2.01). Beverages at pH 2.01 and inoculated by each one of referenced bacteria indicated that the samples which contained thermally stressed bacteria were worse hygienic quality than the same ones which contaminated with unstressed bacteria. Some of recovery percentages of bacteria thermally stressed were significantly higher (P =.05) than those of same bacteria thermally unstressed after acid treatments. That phenomenon was called thermal-induced bacterial acid resistance.
 Conclusion: it appeared that some sublethal cold and heat shock treatments (10°C/45 min, 45°C/45 min, 50°C/90 min and 180 min) could negatively affect food quality. So, the control of emergence and evolution of stress-resistant bacteria in food could help to improve food safety.

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

“…This drop in the spore sensitivity, reflected by the recovery rising, is potentially linked to an increase in the resistance of stressed spores to acidity and some organic substances produced by craft beers. This behaviour, known as thermal-induced bacterial acid resistance, has already been reported by Bayoï et al, [12,13]. These authors reported that sublethal heat stresses at 45°C, 50°C and 60 °C would increase the resistance of B. subtilis and G. stearothermophilus spores to acetic acid at pH 4.5.…”

“…The adapted method to that described by Bayoï et al [13] was used to perform this experiment. Five (5) milliliters of spores (1.6x10 7 cells/ml) suspension of each bacterial species were filled in a pyrex tube, corked, and introduced into a cooling system (Superser, China) or a water bath (Memmert GmbH + Co. KG, Germany).…”

Traditional Processing and Characterization of “<i>Alme Ardeb</i>”, an Indigenous Beverage from Far North Region, Cameroon

“…Like with other drink, the pH of "Alme ardeb" is closely related to that obtained on orange juice (pH 4.49) [22] produced in Algeria and ginger juice (pH 4.4) produced in Mali [23]. However, it is less acidic than "Foléré" juice (pH 1.57) obtained from Hibiscus sabdariffa in Cameroon [4] and cashew apple juice (pH 3.81) produced in Ivory Coast [24].…”

“…The production of beverages from local resources is a very important secular activity among rural people of Cameroon. Foléré juice (Hibiscus sabdariffa) and "kargasok Tea" for examples are the most widely consumed homemade drinks in the Far North region of Cameroon [4] [5]. A drink of the same family is also subjected to multiple handlings and hence the hygienic aspect is often questionable [5].…”

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

“…This experiment aimed to investigate germination behaviour of Bacillus and Geobacillus spores in presence of different traditional beverages with pH values lower than 4.5. To perform this simulation, we used the method earlier described by authors [30]. Sterile tube tests containing 5 mL of pasteurized "foléré" (pH 2.01), red beer (pH 2.63), and white beer (pH 2.8) were inoculated with 100 μL of heat-activated spores of each bacterial strains to result in a final concentration of 3.5x10 6 spores/mL.…”