MILK Symposium review: Microbiological quality and safety of milk from farm to milk collection centers in Rwanda

The aim of this study was to generate knowledge on the most important milk quality and safety attributes, including somatic cell count (SCC), total bacterial count (TBC), Escherichia coli, Salmonella, and Brucella spp. antibodies and antibiotic residues in milk in the chain from farm to milk collection center (MCC) in Rwanda. In addition, we investigated farm and management factors associated with high TBC, SCC, and Salmonella counts. Raw milk was sampled at the farm and MCC levels. Milk samples were taken from dairy farms linked to 2 selected MCC in each of the 4 provinces in Rwanda. In total, 406 bulk milk samples from 406 farms and 32 bulk milk samples from 8 MCC were collected and analyzed. Farm milk average SCC varied between 180 × 103 and 920 × 103 cells/mL, whereas average SCC in milk samples at MCC varied between 170 × 103 and 1,700 × 103 cells/mL. The mean milk TBC of different farms per MCC varied between 1.1 × 106 and 1.6 × 107 cfu/mL, whereas in milk samples from different MCC, the mean TBC ranged between 5.3 × 105 and 2.4 × 108 cfu/mL. The high TBC in milk from MCC suggests proliferation or recontamination of milk by bacteria during transportation. Escherichia coli was detected in 35 of 385 farm milk samples and ranged between 5 cfu/mL and 1.1 × 104 cfu/mL, whereas in milk samples from the MCC, it was detected in 20 out 32 samples varying between 5 cfu/mL and 2.9 × 103 cfu/mL. Overall farm prevalence of Salmonella in milk samples was 14%, but no milk samples from MCC were positive for Salmonella. Five out of 22 bulk milk samples from different MCC were positive for Brucella spp. antibodies, but no Brucella antibodies were detected in milk samples from farms. The prevalence of antibiotic residues as detected by the Delvotest SP NT (DSM, Delft, the Netherlands) was low: 1.3% in farm milk samples and undetected in MCC milk samples. Lack of a separate milking area was associated with high TBC, whereas offering of supplemental feeds, keeping data of past diseases, and an unhygienic milking area were associated with high SCC. Lack of teat washing before milking was the only factor associated with Salmonella contamination of milk at the farm level. This study indicated high TBC and SCC of milk samples at the farm and MCC levels, which indicates both microbial contamination of milk and poor udder health in dairy cows. Presence of E. coli, Salmonella, and Brucella antibodies in milk was common, but finding antibiotic residues in milk was uncommon

Characterization of meat retail conditions in Kigali city (Rwanda): hygienic practices and determinants for Salmonella occurrence

Salmonella is one of the leading bacterial food borne pathogens worldwide and meat constitutes one of the major vehicles for human Salmonella infections. Salmonella illnesses represent an important public health concern particularly in countries with growing economies such as Rwanda. The objective of this study was to characterize the retail conditions and to determine the microbiological quality and safety of meat retailed within the establishments of Kigali city. A survey was carried out in 150 establishments of Kigali city to characterize the meat retail conditions through a structured questionnaire, whereas 270 meat samples were analyzed for the enumeration of hygiene indicator bacteria and the qualitative detection of Salmonella by using conventional culture methods. Furthermore, the risk factors associated to the occurrence of Salmonella in the commercialized meat pieces were identified trough a binary logistic regression analysis. The first results from this study indicate that beef is the type of meat sold the most within retail premises of Kigali city and meat from animal species other than bovines are generally commercialized in large establishments. The levels of hygiene indicator bacteria were found to be relatively high and Salmonella was detected in 19.6% of all retailed meat samples. Factors such as the exposition of retailed meat at ambient temperature, the utilization of wooden cutting boards with rough surfaces which are difficult to sanitize as well as the lack of trained personnel in hygienic meat handling practices; were found to be significantly associated to the risk of Salmonella occurrence in the retailed meat. The findings from this study highlight the need for improvements in hygienic meat handling practices particularly in small and medium meat retail establishments in Kigali cit

Main microorganisms involved in the fermentation of Ugandan ghee

Mashita, a traditional fermented butter-like product is widely produced in western Uganda. However, no detailed studies have been done to identify the microorganisms involved in mashita fermentation. Therefore, the aim of this study was to identify the microorganisms involved in mashita fermentation using culture-dependent and culture-independent techniques. The most commonly identified strains of lactic acid bacteria (LAB) in mashita using culture-dependent techniques were Lactobacillus paracasei, Lactobacillus helveticus, Lactobacillus plantarum and Lactobacillus perolens constituting 37.3%, 10.1%, 8.1% and 7.7% of total bacterial colonies isolated respectively. L. paracasei was the only bacterial species identified in all mashita samples. PCR-DGGE results indicated that acetic acid bacteria (AAB) and LAB were the dominant bacterial groups in mashita. Acetobacter aceti, Acetobacter lovaniensis, Acetobacter orientalis and Acetobacter pasteurianus were the main species of AAB identified in the mashita whereas Bifidobacterium sp., Enterococcus faecium, Lactobacillus brevis, Lactobacillus helveticus, Lactobacillus acetotolerans, Lactobacillus sp., Lactococcus raffinolactis, Lactococcus sp. and Streptococcus salivarius as the main strains of LAB in mashita. PCR-DGGE of the D1 region of yeasts showed that Brettanomyces custersianus, Candida silvae, Geotrichum candidum, Issatchenkia occidentalis, Issatchenkia orientalis, Kluyveromyces marxianus, Saccharomyces cerevisiae, and Trichosporon asahii were part of the mashita microbial community. These results indicate that AAB, LAB and yeasts are involved in mashita fermentation

Risk factors for Salmonella contamination in meat based dishes consumed outside the household in Kigali, Rwanda

Meat is world widely known to be a nutrient rich food. It provides valuable amounts of proteins, vitamins such as retinol and vitaminB12 and minerals namely iron, selenium and zinc with an increased bioavailability than found in other dietary sources. Along the production chain, meat can get contaminated by a wide range of spoilage and/or pathogenic microorganisms. Salmonella is reported to be the causal agent of 33% of food borne outbreaks of bacterial origin attributable to meat. Previous studies have indicated Salmonella prevalence of 3.4% in meat based dishes consumed within the households of Kigali. However, the consumption pattern as well as the prevalence of Salmonella in meat based dishes consumed outside the household is still unknown. The objective of this study was to determine the meat consumption pattern outside the household’s level and to assess the bacteriological quality of the consumed meat based dishes

Daily intake and bacteriological quality of meat consumed in the households of Kigali city (Rwanda)

Meat is worldwidely known to be a nutrient rich food. It provides valuable amounts of proteins,vitamins such as retinol and vitamin B12 and minerals namely iron, selenium and zinc with an increased bioavailability than found in other dietary sources [1]. Along the production chain, meat can get contaminated by a wide range of spoilage and/or pathogenic microorganisms from the farm, slaughtering environment and distribution. The actual number of foodborne infections attributable to meat is difficult to assess accurately, principally because only a small proportion of illness cases is officially reported. However, by using outbreak data published internationally, Greig and Ravel [2] reported that 12.7 % of reported foodborne outbreaks were attributable to beef while 10.5 and 4.6 % were associated with chicken and pork, respectively. According to the same authors, Salmonella spp. and pathogenic E.coli, respectively, were identified as the causal agents in 32.9 and 34.6 % of foodborne outbreaks of bacterial origin attributable to beef. The objective of this study was to determine the meat consumption pattern in different socio-conomical categories of the population of Kigali city and to assess the bacteriological quality of the consumed meat

A real-time PCR method targeting a gene sequence encoding 16S rRNA processing protein, rimM, for detection and enumeration of Streptococcus thermophilus in dairy products

A real-time PCR method targeting a gene sequence encoding 16S rRNA processing protein, rimM, for specific detection of Streptococcus thermophilus was developed. The designed real-time PCR primers and probe were specific for S. thermophilus JCM20026, LMG6896, LMG18311, OJT101, OJT102 but not Enteroccocus spp., Lactococcus lactis subsp. lactis, and Streptococcus salivarius which are phylogenetically closely related to S. thermophilus and are difficult to identify using culture-based methods. The linear range of the developed real-time PCR method was from 2.7 to 8.6 log CFU ml^[-1] with an amplification efficiency of 96%. Minor differences (about 0.4 log CFU ml^[-1]) were observed between counts of S. thermophilus obtained by culture and real-time PCR method in plain yoghurt and yoghurt containing fruits. Therefore, the developed real-time PCR method could be of potential application in specific detection and accurate enumeration of S. thermophilus in a wide range of dairy products

Risk Factors and Control Measures for Bacterial Contamination in the Bovine Meat Chain: A Review on Salmonella and Pathogenic E.coli.

peer reviewedSalmonella and pathogenic Escherichia coli are known to be the major bacterial agents responsible for human foodborne infections attributable to meat. A review of the specialized literature was carried out to identify the risk factors for bovine meat contamination by these pathogens from the cattle farm to meat consumption. Animal stress during transport to the slaughterhouse and the duration of the lairage period were identified as the key factors influencing the faecal excretion of Salmonella and pathogenic E. coli as well as cattle contamination prior to slaughter. At the abattoir level, hides and visceral contents appear to be the main sources of pathogenic bacteria that contaminate carcasses along the meat production chain. Finally, temperature abuses during distribution and meat contamination by infected handlers were found to be important contributors to the post-slaughter contamination of bovine meat. The findings of this study indicate that efficient management of human food borne infections attributable to bovine meat requires an integrated application of control measures involving all actors along the meat chain, namely slaughterhouses, meat processing plants, distributors and consumers

Meat retail conditions within the establishments of Kigali city (Rwanda): bacteriological quality and risk factors for Salmonella occurrence

Meat constitutes one of the major vehicles for human foodborne infections. This study aimed to assess the retail conditions and to determine the microbiological quality and safety of meat retailed within the establishments of Kigali (Rwanda). A questionnaire survey was carried out in 150 retail outlets to characterise meat retail conditions. Additionally, 270 retail meat samples were analysed for the enumeration of hygiene indicator bacteria (total mesophilic bacteria and Escherichia coli) and for the qualitative detection of Salmonella, using conventional culture methods. The results revealed that beef was the predominant meat sold within the retail premises of Kigali city, while meat from non-bovine animal species was mainly sold in large establishments. Salmonella was detected in 19.6% of all the retailed meat samples evaluated, whereas the mean loads for total mesophilic bacteria and E. coli were 7.3 and 3.5 log cfu/g, respectively. Three factors, namely the temperature conditions of the meat under retail, the cleanability of the used meat cutting boards, and the training of personnel in hygienic meat handling practices, were found to be significantly (p ≤ 0.05) associated with the risk of Salmonella occurrence in the retailed meat. The findings from this study highlight the need for improvements in hygienic meat handling practices, particularly, in small and medium meat retail establishments in Kigali