Previous Page Table of Contents Next Page

Chapter 4. Milk collection, processing and marketing

So far we have dealt with the issues related to forming and developing groups. This chapter describes milk collection, processing and marketing activities. In the context of this book we cannot go into the detail of every activity, but information sources will be given whenever appropriate. Other activities will be dealt with in chapter five and participatory tools in chapter six.

FAO dairy information page

4.1. Milk collection and transport

4.1.1. Milk collection

Milk collection is often one of the first activities of milk producer groups. Once the milk from several group members is collected in a central location, the milk can be processed or transported to processing centres or markets. Milk should be collected within four hours of milking.

starting a milk collection centre

A decision should be made on the number and sites of collection centres that are needed in the area covered by the group. Many factors influence this decision:

A participatory tool to decide on the numbers and the sites of the collection centres is given in section 6.2: ’milk production map‘. By discussing this map with the group members, you can decide on the best areas for starting a collection centre.

milk production map

selecting a site for a collection centre

In selecting the ideal site for a collection centre, consider the following points:

If the group plans to process the milk in the future, you might want to select a site that can also be used as a site for a processing centre. In this case it is essential that electricity is available.

constructing a collection centre

Whether you are going to construct a building or a shade depends on the funds available. An open shade is often sufficient for collecting the milk, simple testing and transporting to the processing centre. If you want to construct a building, it is best if the floor is a hard washable surface. If the group plans to expand its activities in the future and wants to include milk processing, it might want to construct a building that can also be used for this purpose.

4.1.2. Hygienic milk collection

Hygiene at all stages of milk collection and processing is very important for the quality and shelf life of dairy products. The farmer could provide containers or the group may provide and clean standard milk churns to improve hygiene. Important points for good hygiene are:

If some group members have refrigerated storage facilities, it may be necessary to provide separate collection for this pre-cooled milk.

cleaning and disinfection

There is a difference between cleaning and disinfection. Cleaning removes materials such as dirt and any residues of milk, disinfection kills most harmful bacteria. Clean the containers as follows: Rinse with cold water first, then scrub with a brush and warm water containing detergent and rinse again with cold water. Sterilize with boiling water (or use disinfecting solutions like hypochlorite), dry the cans on a drying rack (preferably in the sun).

hygienic milk handling and processing, milk processing guide series, volume 1, on FAO dairy information page

4.1.3. Milk collection records

Keeping records of all milk that is collected is important for all the reasons specified in section 2.3: ’keeping records‘. Table 2 shows an example sheet of weekly milk collection records. This includes results of milk testing, in this case the lactometer reading (density) and the fat percentage (see 4.2.2: milk testing).

Table 2: example sheet of weekly milk collection records








Sunday morning

Sunday evening

Monday morning

Monday evening

Tuesday morning

Tuesday evening

Wednesday morning

Wednesday evening

Thursday morning

Thursday evening

Friday morning

Friday evening

Saturday morning

Saturday evening




4.1.4. Milk preservation

Milk should be cooled immediately after milking, and be kept as cold as possible before processing. The best temperature to keep the milk is 4 degrees Celsius (or below), but in most developing countries this requires some kind of cooling equipment. The most important preservation methods are given below:

cooling methods

1. keep the milk in the shade not in the sun;

2. keep the milk in a well-ventilated place;

3. use cold water to cool the milk (You can for example put the milk in a water bath, or in a stream);

4. use ice to cool the milk;

5. use the following cooling equipment:

Lactoperoxidase System of milk preservation

The Lactoperoxidase System is a safe milk preservation method that can be used in situations where milk transportation from farm to processing unit takes a long time and where no cooling facility is available or affordable. It is intended for use by trained people at the level of collection points, not by individual farmers. Lactoperoxidase is an enzyme that exists naturally in milk and slows the growth of spoiling bacteria. The effect of Lactoperoxidase depends on the temperature, but even at 30-degrees Celsius, it can prevent souring of the milk for 7-8 hrs (if the initial hygienic quality of the milk is reasonably good).

The Codex Alimentarius Commission has approved the use of the Lactoperoxidase system of milk preservation. Whether this system can be adopted is dependent upon your country’s regulations. The Lactoperoxidase system is not an alternative for clean milk production but it delays bacterial growth and helps to maintain the milk in as healthy a condition as it was when drawn from udder. This system is only applicable if refrigeration is not available or practical.

FAO Lactoperoxidase website, on FAO dairy information page

4.1.5. Milk transport

Group transport can be arranged for individual supplies of milk. There are many ways to transport the milk; this could be by truck, rail, boat, bicycle, animal or foot. The group has to decide on the most appropriate way to transport milk in order to keep the transport costs as low as possible. The advantage of transporting milk in small containers is that poor quality milk is not mixed with good. Milk transport from the farm to the collection centre, processing centre or factory should always be as quick as possible to prevent spoilage of the milk.

Hygienic milk transport is also important. Clean the containers used for transport every time: rinse with cold water first, then scrub with a brush and warm water containing detergent and rinse again with cold water. Sterilize with boiling water (or use disinfecting solutions like hypochlorite) and dry the containers (preferably in the sun).

4.2. Milk testing and payment systems

ILRI Rural Dairy Technology Manual

When milk arrives at the collection centre, information on the milk is needed. This information could be quantity, quality, hygiene, composition, whether water has been added, etc. This is needed to determine the amount of money that milk producers will get. The level of information required depends on many factors.

4.2.1. Milk sampling

It is expensive to analyse all milk supplies on a daily basis for all parameters. To avoid this, you can sample the milk and place it in sample bottles with preservatives added. Potassium dichromate can be added to keep the samples (for fat testing) in a good condition. Testing can be done on a mix of these samples. Alternatively, milk can be sampled and tested on a random basis. Always try to keep milk samples cool (close to freezing point), but make sure the milk is heated to 40°C and then cooled to 20°C and mixed before testing. Milk must be thoroughly mixed before sampling to make sure that the fat is dispersed throughout the container. Make sure the samples are labelled and carefully recorded to avoid confusion.

4.2.2. Milk testing

The methods used for milk testing are usually related to the payment system adopted. The different methods for milk testing are briefly described below, with an emphasis on simple and cost-effective methods. These focus on milk reception tests that can be carried out at collection centres. For a more detailed description of the tests and for other tests see technical books in the information sources at the end of this book.

quality testing

Milk testing for quality can be divided into testing for hygiene and for composition. You always have to balance between the costs and benefits of the tests, because testing regularly can become very expensive! Make sure you always clean milk testing equipment thoroughly after use: you can use boiling water for at least one minute, 70% alcohol, or keep the equipment in a flame. Some examples of tests, in order of cost and simplicity are described below:

1. taste, smell, visual observation and temperature

This should always be the first screening of the milk, since it is cheap, quick and does not require any equipment. These tests are also called ’organoleptic tests‘. It is also reliable if the person carrying out the tests is experienced. The tester smells the milk, observes the appearance, tastes if necessary, checks the can for cleanliness, looks for sediment, and filters the milk to check its cleanliness. If doubts arise after the examination about the quality of the milk, other tests can be done to determine the quality.

2. density meter or lactometer test

With a lactometer the specific density of milk is measured. At 15 degrees Celsius, the normal density of the milk ranges from 1.028 to 1.033 g/ml, whereas water has a density of 1.0 g/ml. So when you read the lactometer, you can determine whether water has been added to the milk. It is best to combine the lactometer reading with the fat test: if the results of the fat test are low and the density is high (e.g. 1.035), then the milk might have been skimmed. If the results of the fat test are low and the density is low (e.g. 1.027), then water might have been added to the milk. You can use the lactometer reading together with the fat percentage to estimate the Solids Non Fat (SNF) content of the milk (see milk payment systems, method 3).

Always read the temperature of the milk first: the lactometer reading varies according to the temperature. Make sure you adjust readings as indicated in table 3 below.

Table 3: temperature adjustments for lactometer readings

Temp (°C)










- 0.007

- 0.005

- 0.003






3. clot-on-boiling

The clot-on-boiling test is simple, quick and cheap. If the milk is sour or if the milk is abnormal (colostrum or mastitis milk) the milk will not pass this test. Place test tubes with 5 ml of milk for up to 4 minutes in boiling water or in a flame. Examine the tubes and reject the milk if you can see the milk clotting. Please note that at high altitude milk boils at a lower temperature. This test is not very sensitive to slightly sour milk and an alternative is the alcohol test.

4. alcohol test

If the milk is sour or if the milk is abnormal (colostrum or mastitis milk) the milk will not pass the alcohol test. You carry out the test by mixing equal amounts (2 ml) of milk and a 68% ethanol solution (made by mixing 68 ml of 96% alcohol with 28 ml distilled water). Milk that contains more than 0.21% acid will coagulate when alcohol is added.

5. acidity test

This test measures the lactic acid in the milk. If the acidity is higher than 0.19%, then the milk quality is poor and cannot be processed. If the acidity is lower than normal (e.g. 0.10% lactic acid) then the milk is of poor bacterial quality or sodium hydroxide/bicarbonate might have been added. For this test you will need a white porcelain dish, a 10 ml pipette, a 1 ml pipette, a burette (0.1 ml graduations), a glass rod for stirring, a phenophtalein indicator solution (0.5% in 50% alcohol) and a 0.1 N Sodium Hydroxide solution. Measure 9 ml of the milk into the dish, add 1 ml of phenophtalein and from the burette, slowly add the 0.1 N sodium hydroxide solution while mixing continuously, until a faint pink colour appears. The more Sodium Hydroxide you have to add before it turns pink, the more acid the milk.

6. Gerber test for fat

This test is used to determine the fat content of the milk. 10.94 ml. of milk at 20 degrees Celsius is added to a butyrometer together with sulphuric acid and amyl alcohol. After centrifugation, the sample is put in a 65 degrees Celsius water bath and read after 3 minutes. The fat content from this reading should not be less than 3%.

4.2.3. Milk payment systems

The first thing to do before setting a price for the milk is an inventory of prices and payment systems existing in the region. Check whether the milk price has to be approved by a milk board or governmental department. Milk can be priced according to:

When the group is just starting collection, it may be possible to confine milk screening to the visual method and pay on a volume or weight basis (see Payment Method 1 below). This has the disadvantage that milk of a better quality is not rewarded and that there is no incentive to improve milk quality. Since most payment systems are based on solid contents, it is more appropriate to measure the weight of the milk (1 litre of milk averages 1.031 kg). The yield of milk products will depend on the amount of total solids present. The greater the amount of fat and protein in milk the greater the yield of cheese, and milk with a high fat content gives more butter than milk with a low fat content.

In the interests of equity and in order to promote quality improvement, it is desirable that a payment scheme with bonuses for quality is introduced at an early stage. You will have to make sure the cost of such a payment and testing system is not higher than the advantages gained (see payment method 2 and 3 below).

There are many other, more complex payment systems based on protein, cell count or other parameters, but in the context of this book these will not be described. For the examples below, the following background information is used:

payment method 1. Based on volume or weight

Background information for examples: (@ is a money unit)

Base milk price: 5 @/kg
Milk Producer 1: 20 kg milk with 4.2 % fat, density 1.036
Milk Producer 2: 20 kg milk with 3.5 % fat, density 1.032
Milk Producer 3: 20 kg milk with 2.8 % fat, density 1.028

This is the simplest method and it is easy to calculate. You can use a weighing machine or a spring balance. Be aware that a spring balance easily gives inaccurate readings and you might have to adjust the balance frequently.

example method 1:

Producer No.

Kg milk


Total price
















@ is a money unit we use in this book

advantages of method 1:

disadvantages of method 1:

To make this method more sophisticated, you can refuse any milk below a certain density to deter milk producers from adding water to it. You can also think of a penalty for low fat (see below):

Penalty for low fat

You could introduce a penalty for milk delivered with a fat percentage below 3.0 %, for example with a 2.8 % fat content:

Penalty below 3.0 % fat = -2.0 @ x (3.0 - fat %) x kg milk

The milk producer number 3 will now get less money for his/her milk:

His/her penalty will be: -2.0 @ x (3.0 - 2.8) x 20 kg = -8.0 @

Price = 20 kg milk x 5 @ = 100 @ - penalty = 100 - 8 = 92 @

payment method 2. Based on fat amount

This payment method is based on the amount of fat a producer delivers. In this example we use the amount of fat (in kg) rather than fat percentage, because this will discourage farmers from adding water. If you use fat percentages, this means that a farmer would get more money if he or she adds water to the milk. For example:

To prevent this from happening, it is better to use a payment system based on kilograms of fat. For example:

Milk price for 3.2% fat is 5.0 @ per kg

Milk price for 4.0 % fat is 5.2 @ per kg

A farmer with 20 kg milk with 4% fat (total amount of fat is 0.8 kg) will get (20 x 5.2 @ =) 104 @. If this farmer adds 5 kg of water to his milk, his fat percentage will go down to 3.2 % (0.8 kg fat/25 kg), but he will get more money for his milk despite the lower price per kg (25 x 5.0 @ =) 125 @!!!

example method 2:

Milk price is 142.90 @ per kg of fat

Producer No.

Kg milk

fat %

total kg fat

Total price



















@ is a money unit we use in this book

advantages of method 2:

disadvantages of method 2:

payment method 3. fat and solids non fat (SNF)

This method is based on the fat and SNF content of milk. The yield of milk products will depend on the amount of total solids (TS) present. The greater the amount of fat and protein in milk the greater the yield of cheese, and milk with a high fat content gives more butter than milk with a low fat content.

calculation of TS and SNF

Total Solids can be estimated from the corrected lactometer reading (L).

Once you have the TS, you can estimate SNF as follows:

example of SNF calculations:

Producer No.

fat %


TS %

















payment system

The payment system is based on a price for fat and a price for SNF. The price of the milk can be calculated according to the formula:

example method 3:

Milk price for fat is 50.9 @ and for SNF is 33.9 @ per kg.

Producer No.

Kg milk

fat %


Total price



















@ is a money unit we use in this book

advantages of method 3:

disadvantages of method 3:

frequency of milk payments to members

Frequency of milk payments can be daily, weekly, once every two weeks or on a monthly basis. Where the milk price is based on average composition for a period of two weeks or monthly averages, the interval between payments is normally two weeks (4 to 6 weeks after first delivery). Intervals longer than 6 weeks should be avoided. On the other hand, daily payment for very small quantities of milk increases administration work and raises costs.

seasonal variations in price

In all countries, whether in temperate or tropical zones, there are strong seasonal variations in the milk volume produced and often there are two prices for milk; low and high seasonal prices.

how to calculate the base producer milk price?

You will first have to calculate all the costs for the group. Consider the following:

From these data you will have to determine the market price for milk or milk products. If all the milk goes to the factory and quantities are substantial, you may be able to negotiate the price. If the group wishes to sell the milk themselves you will have to know the market price of milk in the area, and decide on the price at which you want to sell the milk. You may already have some information on milk prices from the participatory dairy survey (see step 2 of section 2.1: forming groups step by step). You will have to increase the milk price if you want to establish a fund for the group or if you want to make a profit. More information can be found in the description of the feasibility study in section 4.4.

cost of dairy support services

You should think of how to pay for the dairy support services the group is going to introduce. You could for example start a ’dairy development fund‘ whereby you lower the milk price by 10% for milk producers. These funds can then be used for training, to buy animal feed, to set up an artificial insemination service or any other dairy support service.

4.3. Milk processing

ILRI Rural Dairy Technology Manual

Milk processing converts liquid milk into dairy products like pasteurized liquid milk, yoghurt, butter, cheese, ghee and so on. Reasons for processing are:

Small-scale processors can produce a wide range of dairy products. In deciding which dairy products the group is going to make, it is best to carry out a detailed market/feasibility study (see section 4.4). Milk products can be processed as illustrated in figure 4.

pasteurized milk

Pasteurization is the most commonly used heat treatment for milk. Before processing, the milk should preferably be tested for bacterial quality. You then filter the milk to remove particles. Pasteurization is the process of heating milk just enough to kill harmful micro-organisms without destroying flavour and nutritional qualities. Milk is heated to either 63-65°C for 20-30 minutes or 72-75°C for 15-30 seconds. The simplest equipment required is an open boiling pan over a fire. A steam jacketed pan (or pressure cooker) would improve the heating process and can be fitted with a stirrer to improve the efficiency of heating. Pasteurized milk has a shelf life of 2-3 days, and up to 12 days if kept at 4°C.

figure 4: milk processing options

STANDARDIZATION: making milk with constant butterfat through partial skimming.
HEAT TREATMENT: destroying any potential pathogenic germs by heating to a minimum of 63°C for 30 minutes.
CLOTTING: changing from liquid to (semi-) solid by adding starters and rennet;
CURD SEPARATION: after coagulation the milk is separated into whey and cheese curd;
RIPENING: cheese texture becomes homogeneous and develops aroma;
CHURNING: cream is churned to produce a semi-solid product that becomes butter;


When milk is left to stand for some time, fat globules rise to the surface forming a layer of fat (or cream). This can be separated leaving behind skimmed milk as a by-product. There are different types of cream each with different fat concentrations: single (or light) cream contains 18 per cent milk fat whereas double (or heavy) cream normally contains 48 per cent milk fat. Cream is a luxury item and may be used in coffee, as a filling in cakes, or as an ingredient in ice cream. Separation can be very simply achieved by removing the cream with a spoon, but this is a slow process during which the cream may spoil. For this reason it is more usual to use a manual or powered centrifuge separator.


Butter is a semi-solid mass, which contains approximately 80-85 per cent milk-fat, 15-16 percent water and 2 percent solid-non-fat. It is yellow/ white in colour, with a bland flavour and a slightly salty taste. Butter is a valuable product that has a high demand for domestic use in some countries and as an ingredient in other food processing (e.g. for confectionery and bakery uses).


Ghee is almost entirely butterfat and contains practically no water or SNF. Milk or cream is churned and then the water is evaporated at a constant rate of boiling. Ghee is a more convenient product than butter in the tropics because it keeps better under warm conditions. It has low moisture and SNF contents, which inhibits bacterial growth.

fermented milk

In various countries, milk is fermented with a mixture of bacteria (and sometimes yeast). The acidity (and alcohol) prevents the growth of micro-organisms, and the fermentation preserves the milk for a time. As an example, yoghurt is produced by adding a mixed culture of Lactobacillus bulgaricus and Streptococcus thermophilus (in a ratio of 1:1), to convert lactose (milk sugar) to lactic acid. Milk is normally heated to 70°C for 15-20 minutes, using an open boiling pan, or a steam jacketed pan. The milk is cooled to 30-40°C and then the culture is added. The product is left at a temperature of 32-47°C for approximately five hours for the fermentation process to be completed, and then immediately cooled to 4°C.


Cheese is made from milk by the combined action of lactic acid bacteria and the enzyme rennin (known as rennet). Cheese is a concentrated form of milk-fat and milk-protein. Hard cheeses have most of the whey drained out and are pressed. Soft cheeses contain some of the whey and are not pressed. In making cheese, pasteurized milk is heated in an aluminium or stainless steel vessel, then starter-culture is added at the rate of approximately 2 per cent of the weight of milk. Rennet is added to facilitate curd forming and should be added at the rate of 1 per cent of the weight of milk. The milk is allowed to stand until it sets to a firm curd. The curd is cut into cubes to separate the whey from the curd. The curd is then cooked at 40°C for a period of twenty minutes to firm it. After cooling, the whey is drained off. The curd is pressed to ensure that most of the whey has been removed, and is then placed in cheese-moulds, and finally pressed with weights. Next, ripening allows the development of texture and flavour. Ripening usually takes place in ripening rooms, where the temperature and humidity are controlled for the optimum development of the cheese. There are many types of cheese, often specific to particular areas of the world.

selecting a processing site

When selecting a site for a processing centre, you should consider the same things that were mentioned for selecting a site for a collection centre (section 4.1): reliable supply of clean water (on average 5 litres of water are used when producing one litre of processed milk); close to the road; good drainage; accessible, close to other buildings, easy to construct a building, no dust, electricity supply. In addition, a site for a processing centre should preferably be close to a market to reduce transport costs; the site should be cool and well ventilated. The collection centre can also be used as a processing centre.

cleaning milk processing plants

When selecting a site for a processing centre, you have to consider the following points. It is best if the floor is a hard washable surface and there is water and electricity available. Walls should be smooth and washable, windows should have mosquito proof netting and doors must be self-shutting.

All equipment you use for liquid milk must be cleaned immediately after use and at least once a day. Equipment you use for butter and cheese must be cleaned as required and not less than once a week. Rinse with hot water first (40-80°C), then wash with a detergent until the surfaces are clean, and rinse again with potable water to remove the detergent. To disinfect the equipment you can use hot water (80°C), steam, or detergents/disinfectants (water temperature 45- 60°C).

4.4. Milk and milk product marketing

In order to generate more income from milk production, the group can decide to market the products themselves, as it is easier to access markets as a group. Knowledge of the markets is essential if you want to make profit, and you should gather as much information as possible.

feasibility Study

Before deciding which products to make, you need to know whether there is a market for the products and whether or not they are likely to make money for the group. It can be harmful for the group, if a product is chosen that does not make any profit. To know whether there is a market, you need to do a feasibility study. You will be able to use some information from the participatory survey (see 2.1, forming groups step by step).

Choose a product that seems to offer the most potential for meeting consumer demands. Please note that the feasibility study will usually take at least a month, but the information collected will be essential for choosing the activities. It will help you avoid investing money, time and energy in an activity that will not make any profit. These are the steps to take:


You first need to know the customers. Finding out what the consumer wants is the key to successful marketing as well as the key building block for a successful milk producer group. You need to be able to answer the following questions:


Secondly, you need to know who is competing with the group for the same customers. You need to be able to answer the questions below:

Some of the information may be available in reports and official statistics, but other information will have to be gathered by talking to or watching customers, sellers and producers. See also section 6.4 on “semi-structured interviewing”.


The next step is to determine what is required to make the product. You have to consider all the costs involved, the labour and financial resources needed, materials and equipment, skills (is training needed?), time, buildings or land (does the group want to start a shop?), transport, licenses, is other support needed? Make a list of all the requirements; it is easy to forget things! Then you need to know where these things come from, and make an estimate of all the costs involved.


When all the information is gathered, it must be analysed. Before making a decision, you have to consider the following opportunities for competing with other products already in the market. Can the group have:

Normally a combination of these methods will be used in order to compete effectively.


Once you have considered all aspects of the previous steps, you have to make a last but crucial assessment before deciding to go ahead. You have to discuss the risks involved with all members, and you need to make sure you can make a profit on each product.

Previous Page Top of Page Next Page