The Microbial Evaluation of Raw Milk From a Dairy Farm
CHAPTER ONE
Objectives of Study
The main objective of this study was to evaluate the quality of milk from small-scale dairy farmers in the Emene Fulani cattle farm in Nigeria.
Specific objectives
The specific objectives of the study were to:
- Assess the knowledge of farmers on quality milk production and dairy animal management practices under small-scale dairy production conditions.
- Evaluate microbial quality of milk from farmers and vendors.
- Assess the milk composition wholesomeness and freedom from drug residues from farmers and vendors
CHAPTER TWO
LITERATURE REVIEW
Contribution of Small-Scale Dairy Farmers in Nigeria
Improved Nutrition
Milk production in Nigeria is estimated to be 2.5 billion litres per year with a population of 45 million the per capita consumption is therefore about 50 litres per person per year (Kaush et al, 2015). This amount is less than the per capita consumption in Kenya which is 100 litres per person per year (Muriuki, 2011) and the world average which is 108 litres per person per year and the amount recommended by FAO of 200 litres per person per year (Kim et al, 2009). The low milk production is due to low milk yield due to few improved dairy cattle estimated to be about 680 000 cattle against the desired number of 3 000 000 improved dairy cattle (Njombe, 2011). In addition, more than 90% of milk from small-scale dairy farmers is marketed informally (Njombe, 2011).
Due to the high nutritive value of milk, it is essential to increase the consumption level so as to improve the nutrition status especially for children and infants less than 5 years of age. Since infants are vulnerable to protein-energy malnutrition this requires that milk provided to this group must comply with the standard nutritive value for milk to form an important component of their diet (Nwankwo et al, 2015). Milk supplies high-quality protein, minerals and vitamins (Achchuthan and Kajananthan, 2012).
Improved Livelihood
Small-scale dairying can be a viable tool in poverty and malnutrition alleviation in low- income societies (Uddin et al, 2012). Sales obtained through selling milk help farmers to earn money that is used to pay for other important services. Small-scale farmers combine crops and livestock. Manure from the animals is used to fertilise their farms and contribute to crops productivity. Dairy production acts as an extra source of income to rural populations which depend only on crops (Amarja, 2013).
Employment
Dairy production has been considered as a potential means of alleviating large scale unemployment, especially in rural areas (Marichamy et al, 2014). There is employment creation along the milk value chain. People are in dairy input supply business, production of milk, marketing of milk and processors. Dairy helps people in increasing the income through selling raw milk and processing of dairy products in small-scale basis which is commonly run by women groups.
Constraints Faced by Small Scale Dairy Farmers
Seasonal and Low-Quality Feeds
There are plenty of feeds during the rainy season and are in deficit in the dry season. This causes milk productivity to fluctuate depending on the feed availability. A study by (Kivaria, 2006) in Dar-es-Salaam Nigeria showed that during the rainy season the distance to forage source was half a kilometre but during the dry season the average distance travelled was over 20 kilometres.
The additional milk produced during the rainy season when feed is in abundance can be processed into high-value products which have longer shelf life and are of high microbial as well as nutritional quality. Examples of such products include sterilised milk, UHT milk and milk powders. Products with long shelf life are available to consumers during the dry season when feed is scarce and milk yields are low.
CHAPTER THREE
MATERIALS AND METHODS
Study Design
Five in Enugu state was include in this study. A total of 180 farmers and 30 vendors were interviewed and data were collected from the participants included the study. Simple random sampling was carried out to select farmers and for the vendors, the available ones were included in the study.
Sample Collection
Milk samples were collected from small-scale dairy farmers who brought their milk to collection centres and milk vendors in respective villages. Labelled pre-sterile 30mls bottles were used to collect the milk sample. Milk samples were collected directly from farmers’ containers at the milk collection centres. The samples were immediately cooled and transported in cool boxes filled with ice packs to the laboratory for analysis.
Determination of Total Bacterial and Coliform Counts
Standard procedures described by (USDA, 2011) was used for Total Bacterial Count and Coliform Count of the collected milk samples.
Preparation of Diluent
Peptone water was used as the diluent. This was prepared by diluting 15.23 grams of peptone water powder into 1000ml of the distilled water. Then 9mls of this solution was added into clean test tubes. The tubes were stoppered by the use of cotton wools and sterilised at 121°C for 15minutes in an autoclave. After sterilisation the tubes were cooled to room temperature and then stored in the refrigerator ready for use in the next day.
Determination of Bacterial Counts in Milk Samples
For Total Bacteria Count, the media used was Plate Count Agar (HIMEDIA REF M091). Standard Plate Count Agar was prepared by dissolving 23.5grams and in 1000mls of distilled water. The solution was heated on a gas cooker to dissolve the media. Thereafter it was sterilised in an autoclave at 121°C for 15minutes. After sterilisation bottles with Agar were cooled to 45°C in water bath ready for inoculation. For Total Coliform Count, the media used was Violet Red Bile Agar (HIMEDIA REF M049). Red Violet Bile Agar was made by dissolving 41.53grams in 1000mls of distilled water. The solution was then heated to dissolve the agar then cooled in a water bath to 45°C.
Plating
For each milk sample tenfold serial dilution (10-1 to 10-6) were made in sterilised test tubes with peptone water. One millilitre each of 10-2 to 10-4 was used for Total Bacterial count and 10-3 to 10-5 for Total Coliform Count as well as E. coli. Plating was done in triplicate in sterilised petri dishes. Twenty millilitres of agar and the diluted milk sample were mixed thoroughly. Plates were allowed to cool and solidify then they were incubated in an inverted position at 37°C. The incubation time for Total Bacterial Count was 48hours and for Total Coliform Count and 24 hours for E.coli.
CHAPTER FOUR
DATA ANALYSIS AND RESULTS
Descriptive Statistics
The results on the grades of the milk in respective to the source basing on EAC legal limit standards shows that the large proportion of milk falls within the acceptable grades. (Table 4.1)
Results for milk samples from both farmers and vendors show a significant difference in TCC and TBC with farmers having a significantly lower TBC and TCC (p<0.05). (Table 4.2)
Table 4.3 shows the mean bacterial counts of milk from farmers in the villages that participated in the study. The highest and lowest counts for TCC were found in Nronga and Lyamungo Kati villages respectively. For TBC mean counts the highest and lowest counts came from samples collected from Foo and Wari villages.
Table 4.4 is showing the mean bacterial counts of milk from vendors in the villages participated in the study. The highest and lowest counts for TCC were found in Nronga and Foo villages respectively. For TBC mean counts the highest and lowest counts came from milk samples collected from Nronga and Foo villages.
Table 4.5 shows that milk samples from both farmers and vendors tested positive for the presence of E.coli all samples tested were negative for the pathogenic strains of E.coli
CHAPTER FIVE
GENERAL DISCUSSION CONCLUSION AND RECOMMENDATIONS
General Discussion
The observed levels of bacteria load for both TBC and TCC in milk from the study area were in the acceptable limits according to EAC Standards because they were below 2×10⁶cfu/ml indicating the improved milk handling by the participants in the study area. There were some few farmers in the study area with mean bacterial count above two million in their milk, the high count in milk samples for these groups of farmers can be explained as the failure of adherence to clean milking and milk production storage and handling as many farmers were using plastic jerry cans to transport their milk to collection centres. The types of containers used were difficult to clean thoroughly. Although the majority of milk samples was within grade II of the milk quality there is need to educate farmers so that quality use of approved milking structures like milking parlours would help in lowering the bacterial counts in milk from farmers in the study area and so the proportion of farmers with high-quality milk increases.
High levels of the total bacterial count of milk from vendors compared to the samples from the farmers can be explained by the lack of cold chain for vendors when transporting milk so increases bacterial multiplication in their milk.
The presence of E.coli in some milk samples for both farmers and vendors reflects the contamination of milk with faecal materials. It poses a risk to the health of consumers of raw milk and milk products from such milk. Milk and dairy products should be free from E.coli (EAC, 2006). Recovery of E.coli from fresh raw milk is an indicator of the possible presence of other pathogenic microorganisms such as Salmonella which are also of faecal origin.
The presence of Sulphonamides and Tetracyclines in milk samples Hai, Turiani and Mlandizi is an indication of lack of adherence to the drug withdrawal period after administration of antibiotics to sick milking animals. This is an indication of dishonesty since from the interviews, farmers admitted that they should not be selling such milk and indicated that they do not sell the milk from animals on treatment. Lack of adherence to the practice can be due to fear of financial losses a farmer will incur due to throwing away the milk.
The fat and total solids content meet the minimum standards required for processing of dairy products. The low levels of adulteration with water could be due to fear of financial loss since most MCC’s use the lactometer as the basis for accepting milk from farmers.
In conclusion, information generated from this study on milk quality in this study can be used in the development of strategies to boost the small-scale dairy sector in Nigeria. The information will also be useful to all stakeholders in the dairy sector in Nigeria.
General Conclusion
The Total Bacterial Count and Total Coliform Count observed results indicate that there is some level of use of hygienic practices among some farmers. While the Coliform Counts in the analysed milk samples were in the acceptable level of raw milk qualities as per EAC. The use of proper containers made of stainless and seamless aluminium cans will reduce this figure even further.
The presence of E.coli reflects milk contamination of faecal origin. Even though no pathogenic strains of E.coli were identified, the coliforms are of public health concern and there is a need for the small-scale dairy farmers to introduce additional measures such as cleaning their hands before start milking, avoid contamination of the milk utensils and milk to ensure proper milking and milk handling hence reduce milk contamination. The physical- chemical properties of milk for all the participated villages were in the acceptable quality for processing.
The study confirmed the presence of Tetracycline and Sulphonamide antibiotics residues in milk from farmers but not from vendors in the study area. The source of these drugs is mostly due to lack of compliance to withdrawal period after administering drugs to the sick milking animals. The presence of antibiotic residues in milk is of public health concern.
Recommendations
Extension of education in all aspects of clean milk production is important in developing awareness among small-scale dairy farmers to follow the set standards procedures for milking and proper milk storage.
The available laws and regulations need to be revised and developed where they are not available to take care of possible sources of spoilage for example replacement of plastic milk storage containers with the use of stainless steel cans for milk storage. These can be easily cleaned and removes the bacteria that build up in milk storage containers and lowers the bacterial counts in milk from the Emene Fulani cattle farm.
Establishing a system in which milk will be graded and priced according to the quality will involve introducing a quality-based payment system. This will have financial rewards for milk which are clean and penalties for low-quality milk. Such a scheme can screen for antibiotic residues and adulteration with other materials such as flour and butter at MCC’s. Other milk tests apart from the use of lactometer at MCC’s such as alcohol test, Resazurin test and Clot -On Boiling test can be included as platform tests.
Educational programmes and awareness campaigns should be conducted by all dairy stakeholders to enlighten dairy producers and consumers on dangers posed by drug residues in milk to public health and the dairy processing industry. The existing food regulations and Acts should be reinforced to take care of drug residues in milk and other dairy products. A weak regulatory structure such as the one currently exists allows farmers to sell milk containing drug residues due to fear of financial losses that occur due to the discarding of the milk with antibiotic residues.
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