Sylvain Leroy Sado Kamdem

Salmonella is a pathogen that causes gastrointestinal illness in consumers. Animal protection regulations are frequently disregarded by certain local populations, and the microbial risks associated with their consumption make this practice a serious public health concern. Highlighting these dangers may support state regulations and reduce consumer demand. Therefore, this study aimed to characterize the genetic diversity of nontyphoidal Salmonella isolates from bushmeat carcasses consumed in the Central Region of Cameroon. A total of 142 fresh carcass samples were collected from local markets for Salmonella isolation. Phenotypically identified isolates were subjected to multiplex polymerase chain reaction (PCR) targeting the InvA gene for the Salmonella genus, the IE‐1 gene for Salmonella ser. Enteritidis, and the Flic‐C gene for Salmonella ser. Typhimurium. For molecular typing, S . Enteritidis and S . Typhimurium isolates were further analyzed using Random Amplification of Polymorphic DNA (RAPD–PCR). Phenotypic analysis detected Salmonella spp. in 117 carcass samples (82.39%), and PCR confirmed 98 of these (69.01%) as true nontyphoidal Salmonella isolates, comprising 93 Salmonella ser. Enteritidis and five Salmonella ser. Typhimurium. Among the 98 confirmed NTS isolates, the InvA gene was detected in 45 (45.91%), and RAPD–PCR profiles were distinct for all isolates. At a similarity threshold of 80%, Salmonella ser. Typhimurium isolates were grouped into three clusters, while Salmonella ser. Enteritidis isolates were grouped into six clusters. This study shows that bushmeat is heavily contaminated with nontyphoidal Salmonella , predominantly S . Enteritidis serovars. These results may support future epidemiological research and help raise awareness of the microbial risks associated with bush meat.

Undernutrition remains highly prevalent among children and adolescents in Cameroon, while increasing rates of overweight and obesity reflect an ongoing nutrition transition and a growing double burden of disease. This systematic review aimed to provide a comprehensive overview of research conducted on nutritional status, dietary intake, and nutrition‐related practices in nursery, primary, and secondary schools in Cameroon. The review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta‐Analyses (PRISMA) guidelines. Four electronic databases (PubMed, ScienceDirect, Google Scholar, and ResearchGate) were searched for studies published between January 2000 and February 2024. The methodological quality of the included studies was assessed using the Joanna Briggs Institute (JBI) critical appraisal tool. A total of 32 studies met the inclusion criteria. Most studies were conducted in urban areas, particularly in Yaoundé (21.8%), Douala (15.3%), and Bamenda (15.3%), while no studies were identified in the South, East, and Far North Regions. Among primary school children, the prevalence of malnutrition ranged from 9.25% to 30.2%. The highest prevalence of overweight and obesity (38.4%) was observed among secondary school students. Stunting was the most common form of malnutrition among nursery and primary school children. Dietary patterns were characterized by low consumption of fruits and vegetables, with up to 57.3% of children reporting no fruit intake over a 7‐day period. These findings highlight significant regional disparities and the coexistence of undernutrition and overnutrition among school‐aged children in Cameroon. Strengthening nutrition education, improving food environments, and implementing context‐specific interventions are essential to address the double burden of malnutrition without exacerbating existing health risks.

Aim: To assess ultraviolet radiation microbial deactivation and impact of different types of packaging during the storage of dried cocoa beans. Study Design: Quasi experimental design. Place and Duration of Study: Department of Microbiology, Faculty of Science, University of Yaoundé 1, between January 2023 and May 2024. Methodology: Dried cocoa beans were used for ultraviolet radiation of 743.6 µW/cm² during 0 to 50 minutes. The total bacteria count, Enterobacteriaceae, Escherichia coli, yeasts, and moulds were enumerated, and the detection of Salmonella was performed. On the other hand, dried cocoa beans were introduced on 5 different packaging, and stored across two seasons, for 180 days and their microbial content and humidity assessed. Results: The study observed that ultraviolet radiation type C with an intensity of 743.6 µW/cm² for 50 minutes reduces total bacteria count (TBC) by 1.62 log CFU/g (98%) and fungal flora by 2.03 log CFU/g (99%). Time of exposure was a significant factor affecting the ultraviolet antimicrobial efficacy. Based on Weibull model adaptation to experimental data, moulds were more sensitive to these radiation (b=0.09) than total bacteria count (b=0.0012). Hermetic bags show the ability to reduce microbial proliferation during the rainy and dry seasons compared to microaerophilic bags and Jute bags. The Hermetic bags also show an ability to resist humidification compared to microaerophilic bags packaging. Conclusion: Ultraviolet radiation for 50 minutes and storage in hermetic packages of cocoa beans can be proposed as alternatives to the only jute bag storage commonly used today in the cocoa sector.

Cocoa beans are often obtained from exposed fermentation and hence may carry many microbial hazards in the production of cocoa‐derived products. The aim of this work was to assess the microbial quality along the production chain of cocoa mass and the effect of mild heat (ambient temperature, 50°C, 55°C, 60°C and 65°C) and cold storage (refrigeration and freezing) of the latter on deliberately inoculated Klebsiella oxytoca , Escherichia coli , Saccharomyces cerevisiae and Aspergillus brasiliensis survival. It was observed that steam pasteurisation and cocoa roasting can reduce the level of cocoa bean mould from 4.82 Log CFU/g to nondetected levels and total bacteria counts from 6.63 Log CFU/g to 1.94 Log CFU/g in cocoa nibs. The refining process was a critical contamination stage as it contributed to increased microbial contamination. Regarding the challenge testing with the four strains, the deactivation potential of the different cocoa mass treatments was directly proportional to the increase in temperature. In general, the order of sensitivity to cocoa mass treatments was Klebsiella oxytoca , Saccharomyces cerevisiae , Escherichia coli and Aspergillus brasiliensis. The results obtained in this work will contribute in providing new approaches to food safety assurance in the cocoa industry, in particular during the production of cocoa mass.

This study aimed to evaluate the effects of Yellow Star on some disorders and risk factors of comorbidity associated with COVID-19. These effects were evaluated in male and female rats by daily gavage (5 mL/Kg of body weight) for 7 and 14 days. The effects on the composition of the intestinal microbiota were evaluated in the feces, and the effects on coagulation, oxidative stress, lipid profile, and atherogenicity were assessed in plasma. Administration of Yellow Star inhibited the growth of Bacteroidetes and stimulated the growth of Bifidobacterium, Lactobacillus, and Lactococcus in both sexes. Yellow Star (p <0.05) inhibits coagulation in rats regardless of sex. We noted an increase in the antioxidant status and a decrease in pro-oxidant status in both sexes. At the same time, a decrease in plasma levels of MDA was noted. Finally, the administration of the Yellow Star resulted in a decrease in the plasma levels of triglycerides, total cholesterol, VLDL, total lipids, and the TC / HDL-c ratio; and an increase in HDL-c. At the end of this work, it seems justified to recommend the consumption of Yellow Star in the prevention and management of certain disorders accentuated by a SARS-CoV-2 infection. Keywords: Yellow Star, COVID-19, dysbiosis, coagulation, oxidative stress, and dyslipidemias.

The present study investigated the seasonal variation of microbial quality of irrigation water and vegetables produced at Nkolondom, Ebogo1 and Meyo farms in the Centre region of Cameroon. The physicochemical analysis of irrigation water was also studied. A total of 81 fresh horticultural products were harvested in the three farms and 27 water samples collected. For microbial quality, total aerobic mesophilic bacteria, total coliforms, E.coli and Vibrio spp were researched. Parameters such as pH, temperature, electrical conductivity, turbidity and total dissolved solids were measured at the water sampling sites. Data collected were analyzed using Statgraphics version 7.1 software. Results showed that total aerobic mesophilic bacteria had the highest count (9.78 log cfu/g) followed by total coliforms (7.5 log cfu/g), while faecal coliforms and Vibrio were the least represented. The maximal number of aerobic mesophilic bacteria was counted in parsley during the dry season (9.78 log cfu/g). The microbiological quality of irrigation water and vegetables was unacceptable, exceeding the standards accepted by WHO and International Commission on Microbiology Standards for Foods limits for safe consumption. These results indicate that the microbial hazard of these vegetables is alarmingly high and that consumers should be aware to take correct actions while consuming them.

Aim: Starchy products are very important in the fight against food insecurity in developing countries, where they are widely consumed. This study is aimed to assess the impact of cooking and storage methods on the spoilage of some cooked starchy products by spore-forming bacteria Place and Duration: Department of Microbiology of the University of Yaoundé I between June 2020 and September 2022 Methodology: In order to better understand the alteration of these foods by spore-forming bacteria, a survey was carried out among some households and restaurant owners in the city of Yaoundé to determine the cooking and preservation methods for cassava, maize and rice couscous. Then, cooking parameters and conservation modalities from the survey were simulated in the laboratory in order to assess the deactivation kinetics of Bacillus cereus. Results: It emerged from this experiment that cooking time varies according to the foodstuffs, the most important being maize. The packaging is mainly done in non-food plastic bags, and the thermos is used more often than the fridge and the pot. Cassava flour was more contaminated in aerobic spore (1.10⁵ spores/g) than maize and rice (5.10³ and 9.10³ spores/g) after cooking of different starchy food enriched with Bacillus cereus spores, their inactivation was more important in rice followed by cassava and maize couscous as indicated by the Weibull scaleparameters which were respectively 1.1; 0.52 and 0.08. It was also noted that increase in cooking time also reduced the time for spores to initiate outgrowth and this time was affected by the type of flour. These two parameters also affected the time of spore outgrowth to 5logufc/g. Conclusion: Storage in the fridge is still the best way to store food, but the thermos flask is more often used. The use of electric thermostats set at temperatures around 60°C would increase the optimal shelf life and significantly reduce the risk of spoilage and foodborne illness.

In this study, a risk assessment on Vibrio parahaemolyticus infections was carried out in order to estimate the likelihood of gastroenteritis for Cameroonians after consumption of roasted shrimp (Penaeus monodon). The Codex Alimentarius Commission framework was used in this study. Based on the distribution of total V. parahaemolyticus in shrimp and literature information indicating that nonhaemolysing carrier strains could be pathogenic to humans, the cooking, and consumption patterns, the daily exposure level generated in this study, and the dose-response model from other studies, the infectious risk was evaluated and quantified by the Monte Carlo simulation. This simulation was realized based on 10,000 iterations using the Model Risk software, version 4.0, in combination with Microsoft Excel. To better quantify the exposure of consumers and the resulting risk of infection, several scenarios reflecting the minimal, average, and maximal exposures were undertaken. According to the results, the 90 confidence intervals for minimum and maximum exposures ranged from 15 to 24 colony-forming units per day (cells/day) and from 160 to 228 cells/day, respectively. Based on the modal scenario, 90 of the population consuming this shrimp is exposed to V. parahaemolyticus loads ranging from 74 to 110 cells/day, indicating a risk of infection ranging from 1.2 to 1.8 cases per million of consumption. The estimated number of annual disease cases based on annual production is between 1 and 10 cases. This reflects a relatively low risk of infection for roasted shrimp. Good hygiene practices during handling, cooking, and storage may help reduce the actual risk.

Aims: Lovastatin is a cholesterol-lowering drug produced by several filamentous fungi as a secondary metabolite. Its concentration in mushroom can be affected by many post-harvest processes. In this study, fruiting bodies of Pleurotus ostreatus grown on corn cobs were used to evaluate the effect of conservation techniques on their lovastatin concentration. Methodology: acid and blanching treatments combined to different processes of fruiting bodies conservation like sun drying, oven drying and canning by autoclave cooking were tested to evaluate their effect on lovastatin concentration. Results: Sun drying, oven drying at 60°C/70°C and canning using autoclave cooking at 100°C did not significantly affect lovastatin concentration. On the contrary, oven drying at 80°C caused the reduction of this compound up to 45.4% with respect to fresh product irrespective of the precedent use of citric acid or blanching treatments. Also, during canning, the use of autoclave heat treatments at temperatures 110 and 121°C for 15 minute caused a significant reduction of lovastatin concentration of about 52.2% and 48.9% respectively compared to the control. In this regards, it can be concluded that processes that use dry thermal treatments higher than 80°C and autoclave heat treatments higher than 100°C will contribute to the reduction of lovastatin, the cholesterol-lowering compound in Pleurotus ostreatus.

Aims: The aim of this study was to assess the in vitro antibacterial activity of selected antibiotics and essential oils alone or in combination, on selected presumptive probiotic lactic acid bacteria. Study Design: Experimental studies. Place and Duration of Study: Department of Microbiology of the University of Yaounde I between August 2017 and December 2017 (5 months). Methodology: The chemical composition of five essential oils was determined by gas chromatography coupled with Solid-phase micro extraction. Then the sensitivity of four lactic acid bacteria to the essential oils and four antibiotics was assessed by the well diffusion and macrodilution method. Subsequently, two essential oils active on these bacteria and broad spectrum antibiotics were combined according to the central composite design plan. Results: In general, the chemical composition of essential oils is very diverse, with the example of carvacrol found only in Origanum compactum at 53.24% and thymol in Thymus vulgaris at 56.19% and in Origanum compactum at 15.28%. The antibacterial activity shows that the majority of antibiotics used are active on the bacteria in the study compared to the essential oils where two were active (Origanum compactum and Cymbopogon winterianus). The evaluation of the combinations of essential oils and antibiotics in terms of kinetics has given us three cases: the first case is the one with no acidity or no growth at all; the second is the one where growth is normal; the third where growth is delayed with a more pronounced latency phase. Conclusion: This study suggest that the effect of essential oils and medicinal plant used alone or in combination to antibiotics on the gut microbiota have to be evaluated for validation as well as their toxicity activities before using them for human therapy.