Marketing, handling and physical quality of raw marketed milk in Tanga region of Tanzania

L Schooman and E S Swai*

Tanga Dairy Trust, PO Box 1720, Tanga, Tanzania
* Veterinary Investigation Centre, PO Box 1068 Arusha, Tanzania
ESswai@gmail.com

Abstract

Milk being a major constituent of the diet, is a highly perishable commodity, vulnerable to spoilage and consequently health risk to consumers if is not adequately handled from production to consumer chain. A rapid field survey was conducted between April and May 2005 on randomly selected 130 households (105 smallholder dairy farmers and 25 indigenous cattle keepers) and 59 Milk Marketing Agents (MMAs) to explore and describe milk production, handling and marketing practices in Tanga region of north-eastern Tanzania. Physical qualities of raw milk produced and marketed by MMAs was assessed by specific gravity (SG) to determine the level of adulteration and occurrence of brucellosis in bulk milk was assessed by performing milk ring test (MRT). Of the 130 households’ interviewed, 44.6%, 32.3% and 23.1% were classified as urban, peri-urban and rural residents, respectively.

The study revealed poor milking hygiene practices and that milk is marketed through a combination of formal and informal channels, with more than 50% of the milk is sold processed, mainly boiled. Direct delivery to primary cooperative and milk collection centres was the largest primary milk outlet for producers, while direct delivery to consumers was the second most common outlets for urban dairy production system. Of the 59 milk samples collected, 33 (56%) were Brucella MRT-positive and 78% of the samples graded satisfactorily based on SG as prescribed by East African Community standards for raw milk. It’s concluded that in order to enhance safe milk production, handling and marketing; implementation of improved hygiene practices and monitoring at all steps through training and education for all key players from production to consumers chain is needed and it should be supported by appropriate institutional  policies, regulations and improvements in infrastructures. 

Key words: Public health risk, raw milk market, Tanga, Tanzania

Introduction

In Tanzania, the dairy industry contributes 30% of the Livestock Gross Domestic Product (GDP), beef contributes 40% and other livestock contribute 30% (United Republic of Tanzania (URT) 2010). Milk production is dominated by smallholder farmers who mainly keep indigenous species. Analysis of milk production and consumption trends for the past two decades shows that production levels have been below domestic demands for milk and milk products (Swai and Karimuribo 2011). After the collapse of Tanzania Dairy Limited (TDL) as a public body at the end of 1997, some producers, particularly smallholder farmers, were suddenly left without a reliable market for their surplus milk. Private initiatives via traditional and new actors emerged to fill the milk marketing gaps. With the expectation of a more open market appearing, prices for milk and milk products were decontrolled outside the main marketing centres mainly large cities and towns. 

Though milk produced by ‘specialist’ dairy herds in Tanzania contributes only about 30% of the total production, it is estimated that it contributes more than 90% of the total milk marketed, as nearly all the milk produced by indigenous breeds is consumed by the rural producers and is not marketed (ILRI 2005; URT 2010). The little that is drawn from the indigenous breeds is derived from herds close to large urban consumption centers. The predominant milk channel for milk supply is through direct sales from farmers to consumers. The second important channel is through small milk traders, who buy milk directly from producers and sell to consumers. Most traders use bicycles, covering between 20-40 km per day, to collect milk from farms and to deliver to markets. Another outlet for milk is hotels, restaurants and milk kiosks. However, dairy co-operatives and medium- and large scale processors have become more and more important over the last years, handling a bigger percentage of the market milk (URT 2010). 

Information on milk handling, quality assessment and marketing linkages along the production to consumer chain is inadequate because no study has been carried out previously in the region. Similarly, the risk posed by the informal milk market expressed as incidence of zoonoses, chemical and drug residues is scanty and not well known (Keating 1987; WHO 2004; Karimuribo et al 2005; Mosalagae et al 2011; Addo et al 2011). Understanding the role of each player, food-borne zoonoses, marketing constraints and opportunities are essential contributing factors toward development of viable dairy industry in the region. 

Therefore, the objective of this study was to explore the dairy handling practices and to understand the milk marketing systems in the Tanga milk shed area, Tanzania.This report provides the baseline information on milk marketing, handling, physical qualities of raw milk produced and marketed in the area understudy. The overall purpose is to provide insights on informed marketing policies decision and to pin- point public health hazards that may be associated with informal milk markets in the region. 

Materials and Methods

Study area 

The research was carried out between April and May 2005 in Tanga which is situated in the northern coastal area of Tanzania. Tanga region lies between longitudes 37º and 39º East and latitudes 4º and 6º South. The climate varies from hot humid coastal lowlands in the east to the cool Usambara Mountains in the north and semi-arid plain in the southwest. There are two rainy seasons in most years (March-May and September-November), and annual rainfall ranges from 250 to 1,400 mm. Day time temperatures vary from 23-28 ºC during the cool season (May-September) to 30-33 ºC during the hot season (December-March). The mean relative humidity is 75% (range 60-90%).

Cattle production system 

Cattle in the area are kept either in traditional herds or at smallholder dairy farms. The type of animals kept under smallholder dairy herds (≤10 graded animals of all ages, breed, and sex and intensively managed) includes taurine breed (Friesian, Ayrshire, Jersey, Simmental) and crosses of these breeds with Bos indicus breeds (Tanzania shorthorn zebu, TSHZ, boran and Sahiwal). The level of taurine blood varies from 50-85%. Traditional herds (≥30 indigenous cattle of all ages and sex and extensively managed) comprise mainly TSHZ and boran. The systems can be divided into urban, peri-urban and rural, depending on the area of farming. Traditional herds are mainly found in the lowlands, mostly in areas that are less suitable for crop production. Traditional cattle are confined in a cattle enclosure at night with dirt flooring. Animals are kept for meat and milk mainly and also for financial security. 

Smallholder dairy farmers keep their cattle under zero-grazing or grazing conditions. The cattle are kept in cowsheds, which range from simple structures with a sand floor and a thatched roof to structures with a concrete floor and iron sheets as roofing material. Whereas the smallholder production system was mainly on a subsistence basis in the past, most of it has now become market orientated. Other livestock species kept of economic importance are goats, sheep, pigs and poultry. 

Study design 

The data bases of farmers under the district livestock department and Tanga dairy development programme (TDDP 1999) were used as the sampling frame. A sampling frame of 1730 smallholder dairy and traditional livestock keepers’ households, comprising 12,500 cattle, was used to select 130 households to participate in the study based on formulae given by Noordhuizen et al. (1997). Simple random sampling using the Excel software (Microsoft Inc., 1999), was used to select the 130 households which resulted in the recruitment of 105 smallholder dairy and 25 traditional livestock keepers. 

Inventory of milk related practices on farm  

At farm level, information such as milking hygiene and practice, milk handling procedures and place of milking from randomly selected 130 farms in and around Tanga city were sought using a structured questionnaire. The questionnaire was administered using the national Swahili dialect by a Veterinary Department staff member, who was trained in participatory research methodologies. Important data recorded included household education level (binary variable: illiterate and primary education), herd size, access to training and the number of years in livestock farming. The total milk flow from smallholder and traditional livestock keepers was estimated and the milk flow was mapped. 

Inventory of milk marketing agents  

A total 107 milk marketing agents (MMAs) were inventorised. Data on milk handling practices by MMAs were collected during the inventory. Limited available information concerning milk quality coupled with logistic problems affected the ability of this study in estimating the required sample size. Similarly, given the fact that most raw milk marketing is undertaken in urban and peri-urban areas where market opportunities are high, the study sampling frame (n=107) was limited to MMAs confined to a radius of 40 km around Tanga City. Sampling frame consisted of all milk collection centres (MCCs), both cooperative and private owned, and kiosks and restaurants (KR) selling milk in town. In addition to these, bicycle boys (BB), who act as traders or middlemen and are important for marketing milk from peri-urban and rural areas around Tanga, were also included. Overall, 59 milk market agents were randomly selected and sampled. 

Data and sample collection  

Data on milk handling practices by MMA were collected during sampling. Important data collected included categorization of MMAs (cooperative/private centre, restaraunts/hotel, kiosk, bicycle boys), number of liters collected/handled per day, number of suppliers, sources of milk (from traditional herds or smallholder crossbred cow), type of containers (plastic or metals) and whether there are any quality checks conducted (based on specific gravity), or pre-treatment of milk prior to selling (cooling, boiling etc). Milk samples (30 ml in duplicate) were aseptically collected from each milk marketing agent by a sterile syringe into sterile bottles for laboratory analyses. The samples were kept in a cool box on melting ice and transported within 5 hrs of collection to the laboratory. The collected milk samples were tested for antibodies to brucella sp and for adulteration  

Determination of specific gravity (density) 

Adulteration with water was tested for by specific gravity (SG) using a lactometer at a standardized milk temperature. The lactometer was allowed to float freely in a cylinder, containing sufficient milk sample until it reached equilibrium and readings taken below the meniscus. A SG below 1.026 kg/litre (EAC, 2006) was considered suspicious of adulteration by added water. 

Brucella Milk Ring Test (MRT) 

The MRT was performed by adding 30 μl of haemotoxylin stained Br. abortus antigen (VLA, UK), both to a volume of 1 ml and 3 ml, of whole milk that has been stored at least 24 h at 4 ˚C refrigerated after collection. The tube was rocked gently to allow for proper mixing of the antigen and the milk. The tubes were thereafter incubated at 37 ˚C for 1 hour. The test is read using a uniform light source. MRT was performed and interpreted according to protocols described by Shafee et al 2011; Gumber et al 2004; Al-Mariri et al 2011.  

Data analysis 

Data collected were entered and managed in an Epi- Info database (CDC, version 6.04). Descriptive statistics were computed for different variables. Continuous and the proportions of categorical variables were computed and compared for statistical significance by Chi-square test at a critical probability of P <0.05. 

Results

Characteristics of the study households 

A total of 25 traditional livestock keepers and 105 smallholders’ dairy farmers participated in the questionnaire. Based on the location of the interviewees, 44.6%, 32.3% and 23.1% were classified as urban, peri-urban and rural residents, respectively. Traditional livestock keepers keep cattle for longer than small-holder dairy farmers, with an average of 19.1 (median 14) compared with 9.4 (median 9) years, respectively. Forty-percent (n=42) of the smallholders dairy farmers had more than primary education compared to 12% in the traditional sector. Two-thirds (66.6%) of the smallholder dairy farmers had at least received training in cattle management through workshop or seminars, whereas traditional farmers learned cattle management alone or from parents (P<0.001). Smallholder dairy farmers had an average herd size of six animals, with larger herds being kept under grazing than under zero-grazing conditions (P<0.001). On the other hand, traditional livestock keepers had an average herd size of 46 animals (median 30) and all were grazers. 

Milking related practices on farm 

Milking at smallholder dairy farms is mostly done in a special crush and in some other cases in the cowshed often with concrete floor, whereas in traditional herds milking takes place in the kraal, with dirt flooring. Washing hands and cleaning the udder before milking is more common practice in smallholder dairy farms than in traditional herds. In case the udder was cleaned, this was done with water. Only a minority of smallholder dairy farms and almost none of the traditional farms cooled milk on farms. All farmers used plastic, not metal, utensils for milking and transporting milk (Table 1). Smallholder dairy farmers sell their milk more often to MCCs or to their neighbors, whereas traditional farms mainly sold their milk to middlemen, who purchased milk on farm and transported it by bicycle to Tanga city. Urban farmers sold their milk more often straight to neighbors or to restaurants and milk kiosks, whereas milk producers in peri-urban and rural areas relied more on MCCs for their market.

Inventory milk marketing channels in Tanga 

The milk marketing channels for dairy production are shown in Figure 1. Twenty-five percent of the milk produced on dairy farms is consumed at home, both family and calf consumption. Twenty percent is direct sales from farmers to consumers in their neighborhood. The other 55% is marketed through dairy cooperatives, middle men, kiosks and restaurants and private processors. Primary cooperatives and private milk collection centers handle most of the milk. It is estimated that 40% of this marketed milk reaches the consumers as raw milk, through direct sales, middlemen and milk kiosks and 60% as processed milk through processors and restaurants.

Figure 1. Milk marketing channels and milk flow from dairy producers in Tanga (2005)

Characteristics of milk marketing agents 

Descriptive statistics for the 59 sampled MMAs are given in Table 2. On average, 800 liters of milk are handled daily by the three categories of agents and most (82%, 662/799) of the market raw milk is handled by MCCs. A quality check of the collected milk is mainly performed at the MCCs owned either privately or cooperatively. The quality check consists of testing SG by using a lactometer, doing an acidity test by adding alcohol and a visual cleanliness check. The MCCs do not process milk, but mainly cool bulk milk for delivery to bigger processors in the region, although some centers do undertake some milk retail. Most of the restaurants and kiosks pre-treat milk, mainly by cooling and boiling, before they sell it to their customers. The MCCs and BB receive 40% and 42% respectively of the milk from traditional herds whereas smallholder dairy sector is the main (91%) supplier of milk for kiosks and restaurants.

 Physical quality of whole milk 

The quality of milk as defined by SG is summarized in Table 3. Milk samples (n=1, 6%) from MCCs, RK (n=6, 19%) and BB (n=5, 42%) had a SG below the standard of 1.026 kg/l. Milk from agents which reported receiving milk mainly from traditional herds had a significant lower SG compared to that from to agents which reported receiving milk mainly from smallholder dairy farms (P<0.05).

B. abortus antibodies were found in more than 50% of all milk samples, with a lower proportion of milk samples positive in the bicycle boys group.

Discussion

This study revealed that the main actors involved in milk marketing are dairy co-operatives, private wholesalers, vendors, hawkers and retailers (Figure 1). Most of these co-operatives own cooling facilities and collect milk from their members and vendors and resell the milk to wholesale processors and household consumers. Most wholesale processors also operate milk collection/cooling centres. As a consequence, the largest single informal market outlet for smallholder farmers, comprising over 20% the marketed milk, consists of direct sales of raw milk from producer to consumer, typically through farmer delivery to nearby households. Other important players in the informal market are small milk traders (mainly kiosks and restaurants), who handle about 7% of marketed milk, and who deliver milk to consumers or other retail outlets. In the more formal market, dairy farmer cooperatives are the largest players, while private dairy processors are thought to capture only some 2%. Dairy cooperatives play an intermediary role, by supplying milk directly to consumers and large dairy processors. The factors driving the continued importance of the informal market are weak regulatory policies, traditional preferences for fresh raw milk, which is boiled before consumption, and unwillingness to pay the costs of processing and packaging. By avoiding pasteurizing and packaging costs, raw milk markets offer both higher prices to producers and lower prices to consumers (De Leeuw et al 1999). Previous surveys in the Kenyan highlands consistently show some 15% higher farm-gate prices and 25-50% lower retail prices through the raw milk market compared to the formal packed milk market (Hooton and Omore 2007). 

Overall, 22% of samples from the three MMAs had a SG below 1.026 kg/l, indicative of adulteration by added water (either intentionally or accidentally), which may also likely to be of poor bacteriological quality. It should be noted that the SG can also be lowered if the milk is aerated, e.g., by shaking during transport. According to Arimi et al (2005) and Kivaria et al (2006), adulteration of milk by addition of water may introduce chemical or microbial health hazards and reduce the nutritional and processing quality, palatability and marketing value of the milk. All the samples with a low SG came from agents where no quality check was done and majorities (42%) were derived from traditional herds and often using plastic bucket containers. Compared to metal utensils, plastic materials are difficult to clean. Moreover, plastic containers are cheap and readily available in the area understudy. Ellis and Goodacre (2006) reported that the practice of adulteration of milk by adding water is more common during the dry season when milk is scarce and market demand is high. Verification of this observation could not be ascertained in the present study due to the reason that sampling was only once carried out during the wet season. 

The results of the present study further revealed that 56% of the bulk milk samples showed ring test positive for Brucella suggesting that more than half of the market milk is derived from herds or animals infected or previously exposed to Brucella spp. pathogen. It must, however, be realized that since pooled milk samples were studied, the finding do not directly reflect the status of individual cows or herds. The proportion of MRT brucellosis positive samples from MCCs was significantly higher than from BB. This could be due to the fact that MCCs bulk milk from a larger number of animals and herds compared to BB. The detection of Brucella antibodies in the milk samples might be due to excretion of the antibodies by infected, carrier or vaccinated cows (Arimi et al 2005; Cadmus et al 2008). This result differs from the findings of Bertu et al (2010) in Nigeria and Omore et al (2002) in Kenya, who reported 13.5% and 3.5% prevalence of Brucella antibodies in bulk milk, respectively. The apparent geographical variation in the prevalence between reports may reflect differences in the levels of natural immunity, management and husbandry practices employed, vaccination status of the animals as well as genetic variation in disease resistance among the breeds maintained in the systems (Omer et al 2000; Martínez et al 2008). 

Conclusions

• Milk in Tanga is marketed through a combination of formal and informal milk marketing channels. Most of the milk, which is marketed through formal channels is quality checked. The quality check, however, does not include testing for microbial contents or brucellosis.
  
  
• The findings of this study highlight the poor quality of milk handled by the producers and MMAs in the region. This is most likely due to poor milking and handling hygiene at farm level, the use of unsterile milk transport equipment and adulteration as reflected by lower SG, and high ambient temperature prevailing in the study area.
  
  
• The presence of Brucella antibodies and the high levels of adulteration are indicative of a potentially hazardous product which is likely to be posing a serious public health risk to consumers, particularly if the milk is not pasteurized or adequately boiled.

Recommendations

• The findings of this study highlight the need to implement improved hygiene practices and to apply effective monitoring throughout the production to delivery chain. Training and education is also needed for all persons who deal with milk production, marketing and processing.
  
  
• Further research and extension is urgently needed to characterize critical quality points and hazards in order to ensure that good quality dairy products are produced and consumed.

Acknowledgments

The authors are very grateful to the livestock keepers and agents who volunteered to donate milk and gave their time to this research. In addition, thanks are due to the laboratory and veterinary field staff of Tanga for their cooperation. 

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Received 29 June 2011; Accepted 14 August 2011; Published 1 September 2011

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