An endeavour to increase shelf life of milk from isolated traditional livestock keepers in Eastern Zone of Tanzania

P Y Kavana, B S J Msangi^*, Y N Msanga, E J M Shirima^* and J K A Bee

Livestock Research Institute, P.O. Box 5016, Tanga, Tanzania
lrc@kaributanga.com,     pkavana2001@yahoo.com
^*Department of Livestock Research, Ministry of Livestock Development, P.O. Box 2066, Dar es Salaam, Tanzania

Abstract

A study to establish amount of milk spoiled and usefulness of Lactoperoxidase (LPS) was conducted in Mbwad and Kilimilang'ombe villages in Kilosa and Handeni districts respectively.

Results indicated that an average of 80 to 100 l of milk/day was discarded at collection centre in Kimamba. The main reason for spoilage of milk were described as mixing of evening and morning milk as well as long distance from production sites to the collection centre. The price of milk was described by farmers as low ranging from 130 to 193 Tanzanian shillings/l of milk. The main farmers argument regarding unsatisfied milk price was that, cattle treatment cost for the period that starts from January to June was 40,000 Tanzanian shillings/animal/month. They claimed high incidences of diseases during this period that elevates maintenance costs of animals. Farmers narrated that prophylactic measures against tick borne diseases were difficult to carry out because 100 ml of acaricide sold at 6,000 Tanzanian shillings. On average, milk production during normal year was 30 l/household/day in Mbwade while production droped to 18 l/household/day in adverse years. Verification of usefulness of Lactoperoxidase indicated that treated milk could stay for 12 hours without spoilage under ambient temperature of 20 ºC. This suggests that milk from isolated traditional farms could be treated and transported to the consumers without spoilage.

Key words: Eastern zone of Tanzania, infrastructures, lactoperoxidase, shelf life, traditional livestock keepers

Introduction

Several studies conducted to characterise the nature and principal causes of poor milk production in the rural areas of the eastern zone of Tanzania have come out with milk marketing as one of the main constraints faced by smallholder farmers (Msangi 2001 and Msanga 1997). Traditional livestock keepers in the remote areas are likely to produce a significant amount of milk but cannot sell the whole produce due to poor transport facilities and infrastructures such as roads leading to difficulties in milk marketing in towns where potential buyers of milk are residing. Although farmers have some traditional methods for preserving milk, their effectiveness is still questionable. Of recently, preservation of milk using Lactoperoxidase system (LPS) was found to be quite effective.

The use of LPS methods for temporary preservation of milk could assist in situations where for technical or economical reasons such as luck of electricity, refrigeration of milk cannot be practiced. The technique involves adding small packets of thiocyanate and hydrogen peroxide to a milk container. Both of these chemicals occur naturally in milk but in quantities that only inhibit bacteria for one to two hours after which milk can get spoiled (FAO 1999). By boosting this natural process, the milk can last for eight to twelve hours long enough to get it to a refrigerated collection point or marketed to the final consumer. Traditional livestock sector in eastern zone of Tanzania is not exceptional as it is also challenged by inaccessibility of livestock products to the market. The market problem is exacerbated by poor infrastructures and unorganised livestock products market chain from isolated rural areas. However, improvement of infrastructures alone is not a panacea to the animal products market problem in rural areas of eastern zone of Tanzania. Improved infrastructures combined with increased shelf life of animal products would greatly alleviate the problem by ascertaining good quality products to distant markets.

The Livestock Research Centre considered the possibility to increase shelf life of milk from traditional isolated rural areas in eastern zone of Tanzania. The study on usefulness of Lactoperoxidase (LPS) in rural areas was conducted from October 2002 to June 2004. The objectives of the study were to establish the magnitude of milk spoilage in isolated rural areas as well as evaluation of the potential of LPS to increase shelf life of milk from traditional livestock keepers.

Material and Methods

Study Area

The study was conducted in Kilosa (036E00, 009S11) and Handeni districts (038E01, 005S26). The areas are semi-arid grasslands that are suitable for pastoralism. High biomass that available in the areas can be fully accessed and utilized for milk production by ruminants. This enables the areas to be potential milk producers. Most of the potential areas in these districts are situated in remote with poor infrastructures that limits market of milk produced.

Methodology

Interview was conducted in Mbwade in Kilosa district to establish amount of milk spoiled before reaching the market or consumers as well as household milk production and consumption levels. Verification on usefulness of Lactoperoxidase for increasing shelf life of milk was done in Kilimilang'ombe in Handeni district. Two sachets namely activators 1 & 2 were mixed in 50 l of milk. The rule of thumb is that thiocyanate (activator 1) is added first, stir for 30 seconds with a clean plunger or ladle then activator 2 (hydrogen peroxide) follow and the contents should be stirred for 2 minutes. Ambient temperature and temperature of milk were recorded. Variation of pH with time in treated and untreated milk was recorded. Clot on boiling test was done after every two hours to determine the time taken for milk to be spoiled after treatment. A pH meter fitted with an automatic temperature rod was used to record changes of pH with time in treated and untreated milk at the interval of 1 hour.

Results and Discussion

The interview in Mbwade revealed that the main breed of cattle is Tanzania Short Horn Zebu (TSZ) with a population of about 4000 animals. Estimated number of milking cows was 1000 providing about 1 litre/cow/day. The main market for milk was Kimamba town where there is milk collection centre. Information from milk collection centres indicated that about 650 to 1800 litres of milk was collected per day during peak milk production. An average of 80 to 100 litres per day was discarded at the collection centre due to spoilage. The main cause of spoilage was explained as a result of mixing evening and morning milk together with long distance covered from production site to the market. The price of milk ranged from 130 to 160 Tanzanian shillings/litre. The price offered by the centre was affected by storage costs that varied between years due to power interruptions. Many farmers claimed that milk price was low because high cost of treatment and prophylactic measures for cattle were not taken into account in milk price setting. It was pointed out that treatment cost per animal per month during the period that starts from January to June was 40,000 Tanzanian shillings while the cost of acaricide for tick borne diseases control was 6,000 Tanzanian shillings per 100 millilitre.

Results in Table 1 indicate that milk consumption among the family members was low despite of relatively high production during best performing years.

Need of milk to generate families' income normally tends to surpass families' milk consumption requirements in many livestock keeping households. Nevertheless, average milk consumption seemed to be above the National milk consumption target of 26 l per person per year. About 0.1 of milk produced per household was traditionally processed into either yoghurt or ghee.

Results in Table 2 indicated that treated milk could stay for 12 hours without spoilage if kept at ambient temperature of 20 ºC.

This suggests that evening milk could be treated and stored under farmers' condition and then mixed with early morning milk in the following day. However, this concept requires further observations as it has been stated earlier that the main cause of spoilage of milk was that farmers mixed evening milk with the morning milk.

Results in figure 1 indicate a four hours phase of stable pH in treated milk implying bacteriostatic period where spoilage micro organisms' activities were impaired.

Drastic drop in pH occurred after 11 hours in both treated and untreated milk. However, the decrease in pH of untreated milk was steeper than that of treated milk. This observation entails that the rate of spoilage after 11 hours was higher in untreated than that of treated milk.

Results in figure 2 indicate that both treated and untreated milk had similar trend of milk temperatures.

This suggests the influence of LPS treatment of milk was neither endothermic nor exothermic. The temperature of milk was largely influenced by changes in ambient temperature and probably  microbial activities.

Conclusion

Milk treated with Lactoperoxidase could stay for 12 hours without spoilage at room temperature.

Mixing of evening and morning milk combined with long distance of transporting untreated milk could be the main reasons for milk spoilage at milk collection centres in eastern zone of Tanzania.

Acknowledgements

The authors wish to acknowledge all colleagues from the Tanga Livestock Research Centre for technical assistant provided. The District Agricultural and Livestock Development Officers (DALDOs of Handeni and Kilosa districts) and their field staff are highly appreciated for their cooperation that smoothened execution of the study. Special thanks are given to Government of Tanzania through Tanzania Agricultural Research Project (TARP II) for provision of fund and laboratory instruments that facilitated execution of the study to a great extent.

References

FAO 1999 Manual of the LP-system in milk handling and preservation. Secretariat of Global Lactoperoxidase Programme, Rome, Italy, pp 31 http://www.fao.org/ag/againfo/subjects/documents/LPM/lpmcover.htm

Msanga Y N 1997 Smallholder dairying in Northeast Coastal Tanzania: Productivity of Crossbreed Cattle and Calf Rearing Systems. PhD Thesis, The University of Reading. United Kingdom

Msangi B S J 2001 Studies in smallholder dairying along the coast of Tanzania with special reference to influence of feeding and supplementation on reproduction and lactation in crossbred cows, PhD Thesis, The university of Reading, United Kingdom