Beware of Milk Safety

The study has revealed that out of 493 milk samples tested, 237 (47.9 per cent) were contaminated with Pseudomonas spp which can cause infections in the blood, lungs (pneumonia), or other parts of the body, while traces of Escherichia coli (abbreviated as E. coli) stood at 42.4 per cent (209 samples).

Some strains of E. coli are known to cause urinary tract infections, respiratory illness, pneumonia, and other illnesses.

“The presence of these bacteria points a direct finger to bad handling and poor hygiene practices, because they indicate that the milk has been in contact with faecal matter.

“Pre-and post-harvest milk handling practices greatly influence contamination and subsequently milk quality and safety. The person handling this milk is either not storing it properly or is not washing hands after visiting the washroom,” the report states in part.


The study by International Livestock Research Institute (ILRI)-Kenya, Wageningen University and Research of the Netherlands, Uppsala University- Sweden, International Livestock Research Institute (ILRI)-Vietnam and Swedish University of Agricultural Sciences was conducted in three counties of Nakuru, Laikipia and Nyandarua.

The study recommends urgent action by enforcement agencies at county and national levels, formal and informal vendors, farmers and milk value chain actors towards improving milk quality as high levels of microbial contamination of milk pose a public health risk to consumers.

According to the World Health Organization (WHO), unsafe food containing bacteria, viruses, parasites or chemical substances causes more than 200 diseases, ranging from diarrhoea to cancer.

Globally, one in 10 people falls ill after consuming contaminated food and 420,000 die of food-related illnesses every year. Under-fives carry 40 per cent of the food-borne disease burden, accounting for 125,000 deaths.

The study titled ‘Milk quality along dairy farming systems and associated value chains in Kenya: An analysis of composition, contamination and adulteration’ showed that 16.7 per cent of samples collected from farmers and a quarter of samples from vendors had been adulterated with water which can introduce contaminants and pathogens and poses a public health risk to consumers.

It was established that the food borne pathogens in the raw milk were derived from several areas including the interior of the udder, exterior surfaces of the animals, environment, milk-handling equipment and personnel.  Other prevalent harmful pathogens included Staphylococcus spp at 3.3percent while 2.9 percent of the samples tested positive for brucellosis antibodies.

The study randomly recruited 50 owners of dairy farms from randomly selected centres in a cross-sectional study. It interviewed them using a pre-tested standardized questionnaire.

The investigators used a spatial framework based on the distance to urban markets to differentiate farming systems into relatively intensive dairy systems in urban locations (UL), semi-intensive dairy systems in mid-rural locations (MRL) and extensive dairy systems in extreme rural locations (ERL).

Additionally, they visited 11 urban centres including Olkalau, Oljororok and Engineer in Laikipia county, Nakuru town, Njoro, Molo and Elburgon in Nakuru county, Nyahururu, Kinamba, Rumuruti and Nanyuki in Nyandarua county, to observe milk handling at bulking, transport and retailing in both the formal and informal value chains.

The 150-ml per sample of raw milk collected were voluntarily provided by value chain actors at formal and informal value chains in UL, MRL and ERL systems.

Also considered for this study were farmers, informal collection centres, informal retailing centres and milk vending machines (ATMs), centralized formal bulking and cooling centres, formal bulking centres and collection centres run by informal bulking agents in all locations.

The Principal Investigators included Messrs Bernard Bett and Luke Korir from International Livestock Research Institute (ILRI)-Kenya, Simon Nyokabi, J. Oosting and Imke de Boer from Animal Production Systems Group at Wageningen University and Research of the Netherlands, Pieternel Luning of Food Quality and Design Group at Wageningen University and Research of the Netherlands and Johanna Lindel of Department of Medical Biochemistry and Microbiology at Uppsala University- Sweden.

They also interviewed agricultural extension officers: three in Laikipia, three in Nakuru and four in Nyandarua, and veterinary officers: two in Nakuru, two in Nyandarua and two in Laikipia.

The researchers established that milk from mid-rural locations farming systems had higher levels of contamination by E. coliStaphylococcus spp and tested positive for milk ring test (MRT) against Brucella abortus than milk from the other locations.

The probe was part of the ‘Local and International business collaboration for productivity and Quality Improvement in Dairy chains in South East Asia and East Africa (LIQUID) project’ which is supported by the Netherlands Organization for Scientific Research (NWO) Science for Global Development department (WOTRO) through the Food and Business Global Challenges Programme (GCP).

According to records from the Ministry of Agriculture, Livestock and Fisheries Kenya yields over five billion litres of milk per year and is the leading milk producer in the region. The dairy sector contributes to approximately 40 percent of the livestock gross domestic product (GDP), 14 percent of the agricultural GDP, and 3.5 percent of the overall GDP in Kenya.

Smallholder dairy farmers produce about 75 percent of Kenya’s total milk supply. Milk consumption rates in Kenya are among the highest in sub-Saharan Africa: between 50 and 150 Litre per capita per year.

Rapid population growth, urbanization and changing food preferences of the middle class have led to a 5 percent increase per annum in the demand for milk and milk products, over the last decade.

The investigation revealed that milk in the informal value chain within the three counties was bulked by small-scale transporters at the sides of the road in unhygienic conditions exposing it to contamination by pollutants and insects.

Milk was transported using motorcycles in its unrefrigerated form in a warm environment, which could enable bacterial growth and lead to milk quality deterioration.

“In the formal, as well as the informal value chains, actors rarely used any protective clothing while handling milk as required by the public health regulations. Some actors operated without the required certificates such as public health certificates and milk movement certificates. In the informal value chain, actors had limited access to sanitation facilities, including toilets and hand washing facilities,” the findings indicate.

According to Kenya Dairy Board (KDB) the formal value chain accounts for approximately 30percent of the total traded milk and is controlled by entities licensed to operate by the KDB.

Informal value chains account for the remaining 70 percent of milk traded in Kenya. These informal value chains commercialize dairy products which have not been industrially-processed, i.e. raw and traditionally-pasteurized milk and dairy products.

Observations revealed unhygienic milk handling practices at the farm level. Some smallholders in mid-rural locations (MRL) and extreme rural locations (ERL) milked their cows in open environments with potential for contamination by flies and dust, which made it difficult to maintain ideal milk hygiene standards.

In extreme rural locations (ERL), the researchers observed that some farmers used calf suckling to stimulate milk trickle down the udders which could contaminate milk. In all locations, the majority of farmers cleaned their hands; however, cleaning was not thorough, i.e. with soap, followed by drying.

Although farmers cleaned cow udders and teats before milking, they used the same water and drying towels for all cows, which increased the risk for transmission of diseases such as mastitis between cows. The majority of farmers did not perform teat dipping,” states part of the report.

According to the investigators in the majority of farms, farmers did not adhere to regulations as regards proper animal waste disposal (i.e. heaps of manure and open slurry pits), proper handling of chemicals (i.e. chemicals in close proximity to cows and feeds), and animal welfare standards (i.e. muddy and wet floors denied cows resting places).

Urban locations (UL) farms had concrete floors and iron sheets covered cowsheds, while mid-rural locations (MRL) and extreme rural locations (ERL) farms kept cows in open grazing areas or in mud floored iron sheet roofed cowsheds.

Overall, the cleanliness of cowsheds in UL was higher than in MRL and ERL, however, manure disposal was a problem in UL. In UL, MRL and ERL, handling and storage of animal feeds were poor, which exposed feeds to weather elements and increased the risk of growth of aflatoxin producing fungi.

Globally, a World Health Organization study found that food-borne illnesses were disproportionately more common in developing countries, noting that “people in developing countries often have difficulty coping with food-borne disease,” For many living at or below the poverty line, food-borne illness perpetuates the cycle of poverty.

The symptoms of food-borne diseases range from mild and self-limiting (nausea, vomiting and diarrhoea) to debilitating and life-threatening (such as kidney and liver failure, brain and neural disorders, paralysis and potentially cancers), leading to long periods of absenteeism and premature death.

And according to statistics from the Institute of Health Metrics and Evaluation, children are especially vulnerable. Diarrhoeal diseases are the number one killer among children aged five years and below and the second deadliest killer among all other age groups.

“Food safety, food security and nutrition are linked. Unsafe food causes diseases, affecting food intake, which, in turn, leads to malnutrition. In the long term, malnutrition affects productivity, physical and cognitive development in children, fueling a vicious cycle of poverty and food insecurity,” WHO says.