Assessment of Raw Cow Milk Quality in Smallholder Dairy Farms in Pemba Island Zanzibar, Tanzania

Evaluation of breeding objectives, breeding practices and reproductive performance of indigenous dairy cows in selected districts of Kaffa Zone, South West Ethiopia

BACKGROUND

Breeding objectives are designed to achieve targeted dairy cow production goals, which can be affected by production type, farmer preferences, environmental factors and genetic factors individually or in combination. Breeding practices, such as both controlled and uncontrolled, and artificial insemination (AI) are the tools used to obtain the desired breeding objectives. The lower reproductive performance of indigenous dairy cows affects the total milk production and calf crops that are produced during their lifetime. Designing appropriate breeding objectives and breeding practices can improve the reproductive performance of dairy cows and their overall production performance.

MATERIALS AND METHODS

The current study was conducted with the objective of evaluating the breeding, practices and performance of indigenous dairy cattle in the south western part of Ethiopia. The districts of Gesha and Chena were purposefully chosen. The study design for the 384 household surveys was a cross-sectional survey with a simple random sample approach. Data analysis was carried out by MS-Excel (2010) and the general linear model procedure of SAS of 2008.

RESULTS

The current study revealed that methods of breeding were predominantly natural-controlled mating, followed by natural-uncontrolled mating and AI in descending order. Breeding objectives were input function, output function, sociocultural and economic functions and assets and security functions in decreasing order of rank. Reproduction performance indexes of indigenous dairy cows age at first service (3.72 ± 0.05 years), age at first calving (AFC) (4.71 ± 0.07 years), calving interval (CI) (1.58 ± 0.03 years), days open (DO) (4.26 ± 0.11 months), services per conception in natural mating (1.4 ± 0.08) and AI (2.73 ± 0.14), age of bull at maturity (4.17 ± 0.74 years), interoestrus interval (23.18 ± 0.61 days), calves crop (7.53 ± 0.22) and the life span of indigenous dairy cow (11.94 ± 0.26 years) were significant (p < 0.01) between two districts, whereas the values of age of bull at maturity and number of services per conception in natural mating were significant (p < 0.05) between districts.

CONCLUSIONS

Using AI and major reproduction performances, such as AFC, CI and DO of indigenous dairy cows in the study area, were very low. Therefore, concerned bodies should intervene to improve reproduction performance through the utilization of AI techniques, with the integration of forage development activities and improvements in livestock health care.

Molecular characterization and antibiotic resistance profile of ESBL-producing Escherichia coli isolated from healthy cow raw milk in smallholder dairy farms in Bangladesh

Background and Aim

The emergence of antimicrobial-resistant bacteria, such as Escherichia coli in milk, is a serious public health concern as milk is considered a complete food and an important part of daily human diet worldwide, including in Bangladesh. However, there have been no reports on the molecular characterization and antibiotic resistance profile of extended-spectrum beta-lactamase (ESBL)-producing E. coli from milk of healthy cows in Bangladesh. Therefore, this study aimed to detect and characterize ESBL-producing E. coli (ESBL-Ec) in milk samples from healthy cows in smallholder dairy farms in Mymensingh district, Bangladesh, and assess the potential risk of consuming this milk.

Materials and Methods

A total of 100 milk samples were collected from apparently healthy cows on smallholder dairy farms. Escherichia coli was isolated from the collected samples using standard methods. The detection of ESBL-Ec was performed phenotypically using cultural methods and genotypically by ESBL genetic determinants using multiplex polymerase chain reaction. Antimicrobial susceptibility testing of the ESBL-Ec isolates was performed using the disk diffusion method with 15 common antimicrobials.

Results

In this study, out of the 100 samples tested, 70 (70%) were found to be positive for E. coli. Among these, 41 (58.6%) strains were identified as ESBL-producing, both phenotypically and genotypically, with the presence of blaCTX-M, blaTEM, and blaSHV individually or combined (blaCTX-M plus blaTEM plus blaSHV). The antibiogram of these ESBL-positive isolates revealed high resistance against commonly used antibiotics, such as ampicillin, cefotaxime, and gentamicin (100%), azithromycin (88%), oxytetracycline (27%), nalidixic acid, cotrimoxazole/trimethoprim (24%), and streptomycin (22%). In addition, one isolate showed resistance to 4th generation of cephalosporin (cefepime). Most importantly, extensive multidrug resistance was found in many ESBL-Ec isolates. However, the isolates were highly sensitive to drugs such as ceftriaxone (100%) and imipenem (100%). This is the first study to detect ESBL-Ec in raw milk from healthy cows on smallholder dairy farms in Bangladesh.

Conclusion

More than 58% of the E. coli isolated from raw milk of healthy cows tested positive for ESBL production and showed resistance to most commonly used antimicrobials which may be alarming for human health. A limitation of our study is that we had a small size of sample collected from one district in Bangladesh. Therefore, a larger sample size covering a wider geographic area, and using multi-locus sequence typing and whole genome sequencing could provide a more comprehensive understanding of the prevalence and characteristics of ESBL-Ec in Bangladesh.

From farm to table: exploring food handling and hygiene practices of meat and milk value chain actors in Ethiopia

Livestock value chains constitute a source of livelihood for meat and milk value chain actors in Ethiopia, from dairy farmers to other associated value chain actors such as milk traders, abattoir workers, public health officials, veterinarians, butcheries selling meats, milk cooperatives, artisanal milk processors, and transporters. The development of these livestock value chains, however, is constrained by poor food safety and quality, while consumers are also exposed to public health risks due to milk and meat value chain actors' food handling and hygiene practices.This study used Photovoice and participant observation to explore meat and milk value chain actors' food handling and hygiene practices in suburban areas of Addis Ababa and neighbouring Oromia in Ethiopia. The results of this study reveal that milk and meat value chain actors' food handling practices are not aligned with the recommended Ethiopian food safety and quality standards. Low compliance with food safety and quality standards reflected a combination of factors such as lack of incentives, poor road infrastructure and low enforcement of food safety standards.Participatory and visual research methods enable a researcher to collect context-aware data that can lead to the development of policies and intervention strategies that reflect local needs and priorities. The results of this study affirm the need to identify socially acceptable and economically viable policies and intervention strategies that are acceptable to all chain actors; and suggest there is an imperative to train milk and meat value chain actors on good hygiene handling practices, improve road infrastructure, and facilitate access equipment such as fridges and freezers that can contribute to maintaining food safety and quality.

Nutritional quality and adulterants of cow raw milk, pasteurized and cottage cheese collected along value chain from three regions of Ethiopia

Milk is a nutritionally rich food for humans. However, fulfilling the quality of milk is a major concern for milk factories, nutrient requirements, and public health. The objective of this research was to assess the composition of raw and pasteurized milk and cheese, evaluate change in milk and cheese composition along the value chain, and identify adulteration of milk. A total of 160 composite samples were determined using lactoscan and conventional approved methods along value chain. Results indicate that there were significant (p < 0.05) changes of in milk composition along the value chain in the study regions. The range values were; total solid (8.41-11.7%), protein (2.25-3.06%), fat (2.16-3.17%), lactose (3.33-4.76%), ash (0.52-0.73%), P (62.7-84.2 mg/100 g) and Ca (78.2-109 mg/100 g) of liquid milk were obtained in all regions. Liquid milk was found to be adulterated by water along the value chains in all regions (ranged from 0 to 24.8%). Formalin (4 samples) and starch (1 sample) were detected at farmer's and collectors' respectively. In all regions, there was no significant (p > 0.05) difference in cheese nutritional quality between farmers and retailers. The grand mean for moisture, protein, fat, total ash, Ca, P and pH values were 77.1%, 17.1%, 1.42%, 1.18%, 37.8 mg/100 g, 88.2 mg/100 g and 3.7 respectively. Comparison of liquid products with the Compulsory Ethiopian Standard (CES) indicates that 80.2% for fat, protein, and SNF in raw and pasteurized milk were below the CES. In conclusion, liquid milk had poor nutritional composition and varied along the value chain in the study regions. Moreover, there is milk fraud where all dairy value chain add water into milk and milk consumers are consuming lower nutrients and paying for substandard liquid milk. Therefore, training should be provided to all value chain to improve the quality of milk products and quantification of formalin and other adulterants need to be further studied.

The governance of quality and safety in Tanzania's informal milk markets

Despite significant economic and social transformation in Tanzania, 95% of the milk produced in Tanzania is marketed informally. Most of this is commercialized raw (unpasteurized) and distributed and sold through informal traders and vendors to low-income consumers, making it an important source of nutrition and livelihoods. While Tanzania's official dairy policy promotes pasteurization and formal industry, in practice the regulatory environment is relatively permissive of informal raw milk trade. We draw on original data from a survey with over 200 informal market actors, and insights from key informant interviews, to examine the context, perceptions and practices that affect quality and safety in the informal milk market in Tanzania. Our insights contribute to the potential for a more realistic and effective engagement with the informal sector, in Tanzania and beyond. Our results show that all informal market actors are concerned with milk quality and safety and take measures to mitigate risk. Loyalty and repeated interactions between buyers and sellers contribute to ensuring milk quality and safety in the absence of formal mechanisms such as testing. Despite this there is room for improvement. Informal actors expressed interest in training and finance to upgrade their premises and equipment and would also like to see improved communication with policymakers. Any future policy interventions should build on the indigenous practices being used by informal actors that already contribute to risk management. Efforts to better understand the informal sector and address the broader challenge of the lack of voice and representation of the informal sector in policy making in Tanzania are needed.

Raw cow milk nutritional content and microbiological quality predictors of South Gondar zone dairy farmers in Ethiopia, 2020

Background

Raw milk is a good growth medium for microbes because of its neutral pH and nutrient content. In Ethiopia; few studies were done to assess the microbial quality of raw cow milk. But, none of them focused on the nutrient content of raw cow milk. Therefore; this study aimed at evaluating raw cow milk nutrient content and predictors of microbial quality of raw cow milk among milk in the dairy farmers of South Gondar zone (SGZ), Ethiopia.

Methods

A community-based cross-sectional study was conducted from January to May 2020. 160 randomly selected raw cow milk, water, and utensil samples each were collected for microbial analysis. Besides, nutrient content indicators such as TotalSolid (TS), and Specific Gravity (SG) were analyzed from milk samples. Sequentially, The Knowledge, Attitude, and Practices (KAP) of millers were also assessed using a pretested structured questionnaire. Chi-square test and multiple linear regression models were used.

Results

The overall mean SG and TS of raw cow milk were 1.027 (95% CI, 1.013-1.039) and 12.55% (95%CI, 12.20%-12.89%) respectively.38.13% had the better nutrient content, and the rest, 61.87% of raw cow milk hadn't the better nutrient content. Besides, the mean (SD) in log CFU/100mL-1of the Escherichia coli count of raw cow milk was 15 (0.3). Educational status, milk handling experience, KAP of milkers, water microbial count, Nutrient content, and microbial load of milk utensils were independently predicted microbial quality of raw cow milk.

Conclusions and implications

The result signifies that the raw cow milk hadn't better nutrient content and the educational status and KAP of milkers, and the qualities of water were the major factors affecting the microbial quality of raw cow milk. It could greatly affect the Food and Nutrition Security of the country. Hence, measures should be taken to enhance the KAP of milkers for improving this enteropathy.

Antibiotics in Dairy Production: Where Is the Problem?

Antibiotics have long been used for the prevention and treatment of common diseases and for prophylactic purposes in dairy animals. However, in recent decades it has become a matter of concern due to the widespread belief that there has been an abuse or misuse of these drugs in animals and that this misuse has led to the presence of residues in derived foods, such as milk and dairy products. Therefore, this review aims to compile the scientific literature published to date on the presence of antibiotic residues in these products worldwide. The focus is on the reasons that lead to their presence in food, on the potential problems caused by residues in the characteristics of dairy products and in their manufacturing process, on the development and spread of antibiotic-resistant bacteria, and on the effects that both residues and resistant bacteria can cause on human and environmental health.

Antimicrobial Residues in Food from Animal Origin-A Review of the Literature Focusing on Products Collected in Stores and Markets Worldwide

The extensive use of antibiotics leads to antibiotic residues in frequently consumed foods. Generally, the main use of antibiotics in animals is to treat and prevent diseases and growth promotion. However, the residues and their breakdown products have several side effects on the human body and, in a broader sense, on the environment. In relation to the human body, the frequency of mutations is increased, the bone marrow is damaged (chloramphenicol), and the reproductive organs of humans are affected. Carcinogenic effects have been found with antibiotics such as sulfamethazine, oxytetracycline, and furazolidone. We summarized data from 73 scientific studies reporting antimicrobial residues in animal products that were freely available for sale. The studies were published in English starting from 1999 till 2021 and identified through the Pubmed search engine. The aims were to find out which antibiotics, legal or illegal, could be found in animal foods worldwide. Which are stable to get into the food chain and exceed the maximum residue limits (MRL) regarding the EU guidelines as a comparison. Reducing antimicrobial residues in food from animal origin and, in addition to this, fighting the tremendous growth and spread of antimicrobial resistance will undoubtedly be one of the most difficult food safety challenges in the coming years.

Microbial quality of raw cow milk and its predictors along the dairy value chain in Southwest Ethiopia

Raw milk may contain pathogenic microorganism that can seriously affect the health of consumers. In Southwest Ethiopia, raw cow milk is consumed more than the processed products, but its microbiological quality and its predictors are not studied well. The aim of this study was to determine the microbial quality of raw cow milk and its predictors along the dairy value chain in Southwest Ethiopia. A total of 150 milk and 300 environmental samples were collected randomly from dairy farms, milk distribution centers, and retailer outlets for microbiological analysis using standard protocols. One milk handler from each milk production or distribution stage was also interviewed to assess the knowledge, attitude, and practices regarding milk handling. Descriptive statistics and multiple linear regression models were used to summarize the data and to identify predictors of milk microbial quality, respectively. As the milk transported from dairy farm to milk retailer outlet, the mean total bacterial count has increased from 5.0 ± 0.3 to 7.2 ± 0.1 log CFU/ml respectively. The mean coliform count of the milk sample was 4.4 ± 0.4 log CFU/ml at the dairy farm and 7.0 ± 0.2 log CFU/ml at milk selling points, indicating the deterioration of milk quality along the dairy value chain. All of the analyzed water samples were positive for fecal coliform bacteria. The highest coliform bacteria were reported from milk storage equipment found at milk retailer outlet with the count of 4.8 ± 0.5 log CFU/ml. Educational status and attitude of milk handlers and the quality of water used to wash milk equipment and hands of milk handlers were the major factors affecting the microbial quality of raw cow milk. The findings of this study revealed that the microbial quality of raw milk in the study area was poor. Hence, improving the attitude and educational status of milk handlers, and the quality of water is an important step to enhance milk quality and consequently to prevent milk borne diseases.

Efficacy of Reuterin and Bacteriocins Nisin and Pediocin in the Preservation of Raw Milk from Dairy Farms

Research background

In the current scenario of milk production in developing and developed countries, several factors influence the shelf-life of raw milk and add significant numbers of microbial contaminants that drastically lower the initial microbial quality leading to milk spoilage by the time it reaches the processing units.

Experimental approach

The present study was undertaken to investigate the biopreservative efficacy of reuterin system along with different combinations of bacteriocins in controlling the initial microflora of raw milk at farm level. Lactobacillus reuteri strain LR47, having effective antimicrobial activity, was shortlisted from our previous study and further characterized for reuterin production and tested in raw milk system.

Results and conclusions

Preliminary testing of the cell-free supernatant from L. reuteri LR47 demonstrated significant growth inhibition of the majority of the tested bacterial indicators of milk spoilage. Further genetic analysis of the L. reuteri LR47 revealed the presence of two genes (pduC and dhaB) involved in the utilization of glycerol to produce reuterin via two different pathways. The strain LR47 was also found to possess comparatively higher capacity to convert glycerol into reuterin when checked through colorimetric assay. In the raw milk biopreservation experiment with reuterin alone or in combination with bacteriocins, the highest level of growth suppression in the total bacterial load and coliform counts was observed in the sample that was treated with a combination of reuterin, nisin and pediocin. The treatment combining these three natural biopreservatives at specific concentrations was able to maintain the initial microbial quality and extend the shelf-life of raw milk by 6 h at 37 °C based on the microbial counts and physicochemical properties, viz. pH and titratable acidity. In conclusion, the results confirm that the use of reuterin in combination with bacteriocins is a promising approach for temporary control of the raw milk microflora and extension of its shelf-life until further processing.

Novelty and scientific contribution

This study demonstrates for the first time the use of reuterin for the extension of shelf-life of raw milk as an alternative treatment method.

A review of microbes and chemical contaminants in dairy products in sub-Saharan Africa

Animal milk types in sub-Saharan Africa (SSA) are processed into varieties of products using different traditional methods and are widely consumed by households to support nutritional intake and diet. Dairy products contain several microorganisms, their metabolites, and other chemical compounds, some with health benefits and many others considered as potential health hazards. Consumption of contaminated milk products could have serious health implications for consumers. To access the safety of milk products across SSA, studies in the region investigating the occurrences of pathogens as well as chemical compounds such as heat stable toxins and veterinary drug residues in animal milk and its products were reviewed. This is done with a holistic view in light of the emerging exposome paradigm for improving food safety and consumer health in the region. Herein, we showed that several published studies in SSA applied conventional and/or less sensitive methods in detecting microbial species and chemical contaminants. This has serious implications in food safety because the correct identity of a microbial species and accurate screening for chemical contaminants is crucial for predicting the potential human health effects that undermine the benefits from consumption of these foods. Furthermore, we highlighted gaps in determining the extent of viral and parasitic contamination of milk products across SSA as well as investigating multiple classes of chemical contaminants. Consequently, robust studies should be conducted in this regard. Also, efforts such as development cooperation projects should be initiated by all stakeholders including scientists, regulatory agencies, and policy makers to improve the dairy product chain in SSA in view of safeguarding consumer health.

Pastoral community practices, microbial quality and associated health risks of raw milk in the milk value chain of Nakasongola District, Uganda

The informal milk value chain in Uganda controls most of the raw marketed milk, albeit of poor quality. A study was conducted to assess the milk handling practices, the bacterial quality and the associated health concerns of raw milk along the informal milk value in Nakasongola District. The cross-sectional study used both qualitative and quantitative methods to obtain information from key players. The qualitative data was categorized and presented into emerging themes. Bacterial contamination of 200 milk samples was determined by morphological and biochemical tests. The antibiotic susceptibility test was done by the disc diffusion method.

Hand milking was carried out mainly by men (92.5%), and most never or rarely practised hand washing (67.5%) during milking. Milk was mainly delivered to mobile milk-collecting centres located under tree shades (50%). The quality of raw milk was affected by poor hygienic, handling and transportation practices. Most participants (75%) were aware of the dangers of drinking raw milk and the requirements to transport milk in metallic cans. Viable bacterial counts above the recommended limit were recorded in 76 samples (38%) that included Staphylococcus aureus (46%), coagulase-negative Staphylococcus (29%), Escherichia coli (12%), Streptococcus agalactiae (8%) and Salmonella spp. (5%). The overall antibiotic resistance was 45% (34/76), which included resistant isolates of S. aureus (17/34), coagulase-negative Staphylococcus (11/22), S. agalactiae (3/6), Salmonella spp. (2/4) and E. coli (2/9).

The raw milk contaminated with antibiotic drug-resistant bacterial pathogens is of public health concern. Thus, measures to improve the quality of milk need to be designed for the pastoral community in Nakasongola district.