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close this bookStrategies for market orientation of small scale milk producers and their organisations. Proceedings of a worshop held at Mogororo Hotel, Mogororo, Tanzania, 20-24 March 1995. (1995)
close this folderSession 4: Milk processing requirements
close this folderMilk processing requirements for satisfying the demand for various dairy products in Tanzania
View the document(introduction...)
View the documentIntroduction
View the documentMilk quality and Marketing
View the documentFermented milk
View the documentButter
View the documentGhee
View the documentMilk/Blood mixture
View the documentOrganisational set-up and training
View the documentConclusions
View the documentReferences

Milk/Blood mixture

This is common among the Maasai. They produce a popular food product of milk/blood mixture in a ratio of 4: 1. This is either during the milk shortage periods or simply to make a desired food product. Blood is drawn from a healthy animal, is beaten with a forked stick to remove fibrinogen (the ability to clot) then added to a specific quantity of milk, at a maximum of 20% by volume. This milk/blood mixture may be consumed immediately or stored and consumed after souring, or it may be boiled to coagulate and stored for future use. This product has a longer shelf life than milk alone. It is given to children or mothers who have recently give birth. It was reported that consumers of this product do not feel cold even when they walk or work in cold environment (Shallo and Hansen, 1973).

Cheese

Cheese is a good concentrated source of fat and protein (Scott, 1981) and as such it has a high nutritional value. Cheese is not much known in Tanzania but is becoming popular among the educated especially those who have lived abroad. TDL produces very little amount of cheese (Lohay, 1977; 1988).

Many cheese varieties require considerable technical skill and equipment in their manufacture. An important aspect of cheese is the treatment of milk with starter culture to produce controlled amount of lactic acid in the curd while many cheese varieties require special storage facilities for ripening. Common cheese made at a smallholder dairy in Moshi/Arusha is Alpine and Pasta filata (Ulicky, 1989). A detailed description of their manufacture is given by FAO-RDDTT (1988). They are simple to make and one women’s group in Hai district produce them (Ulicky, 1989; Kurwijila, 1990).

Five cheese varieties: Queso Blanco, Halloumi, Feta, Domiati and white cheese are relatively simple to make under small holder conditions in Africa using small scale processing techniques, have good yield, stable under tropical conditions and the product proves acceptable to consumers (O'Mahony, 1987),

Rennet availability is a limiting factor since it must be imported and needs foreign currency. Studies at SUA on the use of Bovine pepsin as a rennet substitute were carried out by Wigenge (1989) who extracted pepsin from the abomasa of adult cattle. Mghenyi (1990) produced Past filata and alpine cheese using the crude pepsin extract, with rennet cheeses as control. The results obtained are shown in Table 8.

Table 8: Comparative characteristics of crude pepsin and rennet made cheese

Type of cheese and enzyme

% Total Nitrogen (TN)

% WSN

Ripening indices (RI)

Moisture content at 4wks1

Mean sensory difference2

Bitterness scores/5pts at 6 wks³

Pasta filata:

Pepsin

7.54*

2.05

27.19

37.09

2.30

1.08 NS4

Rennet

10.37*

0.91

8.80

36.18

0.92 NS

Alpine:

Pepsin

7.59*

1.75

23.05

41.24

1.67

1.50 NS

Rennet

6.65

1.64

24.66

37.48

1.25 NS

* dry weight basis; WSN = water soluble N; RI = WSN/TN
1 = initial moisture content 15.3% and 52.6% in Pasta filata and Alpine, respectively.
2 = Sensory difference scale: 1 = slight; 2 = moderate; 3 = much; 4 = extreme
3 = Bitterness scale: 0 = no bitternes; 1 = trace; 2 = slightly bitter; 3 = bitter; 4 = very bitter; 5 = extremely bitter
4NS = Non significant < ¹ 0.05.

The trials show that pepsin dues not adversely affect the quality and yield of the cheese. These results agree with those found at ILCA (O'Mahony, 1987). These results were too few to give any recommendation to the small scale cheese processors in Tanzania. More trials on the extraction, purification and testing of the bovine pepsin are going on at SUA by a Ph.D student.

Also at SUA in the Department of Animal Science and Production, a Latin American cheese made by coagulating milk with lemon juice - "Queso Blanco" has been introduced and found to be an acceptable cheese. Although it needs refrigeration, no rennet and starter culture is needed in the manufacturers shelf life can be increased by curing or smoking. Since it is a low fat product, can be eaten fresh, is cheap because only lemon juice diluted to equal amounts of water; acidification imparts pleasant flavour to the cheese and product yield is good, the cream separated can be made into butter and ghee and the whey left can be fed to animals or consumed by humans (O'Mahony, 1987) as is the case with the Losaa womens group in Moshi, Manufacture of cheese is difficult with small quantities of milk. However, a village cooperative could make cheese and thus widen its products range just as the Losaa womens group in Hai district, Moshi have done. Preliminary observations indicate that cheese making may be a suitable milk marketing option for rural cooperatives that are far from all weather roads. Use of deep freezer technique in the preservation of lactic cultures can extend the usefulness of limited supplies of lactic cultures (Kurwijila, 1990).

Cheese could be coated so as to: increase the protection against mould/years contamination during storage/ripening; improve quality of the ripened cheese; protect the rind against chemical damage during storage and improve the appearance of the cheese (Kuyper, 1990).