Milk Tests Pdf

From this, the percentage of lactic acid can be calculated. The Alcohol-Alizarin test The procedure for carrying out the test is the same as for alcohol test but this test is more informative. Different indicators that cover various pH ranges are used. Equipment used in alcohol test. However these may not be easily available to the emerging small scale to medium scale processors in Kenya.

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Milk from individual farmers or bulked milk from various collecting centres. After the time has elapsed, observe the colour change using a lovibond comparator.

Milk tests pdf

If still unable to make a clear judgement, taste the milk, but do not swallow it. Avoid wetting of the neck of the butyrometer. It is desirable that milk producers should see their milk being tested, and the records should be made available to them if they so require. As milk is essential for health, it should regularly be consumed. When water is added, the specific gravity is lowered towards one.

The freezing point of milk is regarded to be the most constant of all measurable properties of milk. Specific gravity Lactometer test Lactometer is a hydrometer used to measure specific gravity of milk and scale is limited to the specific gravity of milk. If it is positive, it means the pasteurisation process was inadequate and the milk may not be safe for human consumption and will have a short shelf life. Given that fat is the lightest portion of the milk, its removal will increase the lactometer reading. Equipment used in Gerber Butterfat test.

These substances react in the milk and produce acidity. The level of acidity in milk can be expressed in two ways. The test is quick and simple. If the reading is consistently lower than expected and the milk supplier disputes any wrong doing arrange to take a genuine sample from the supplier i.

Immediately smell the milk. Liquid milk in cans and bulk tanks should be thoroughly mixed to disperse the milk fat before a milk sample is taken for any chemical control tests. Butterfat tests are also done on milk and milk products in order to make accurate adjustments of the butterfat percentage in standardised milk and milk products.

Back to Facts for Farmers. Lactometer is a hydrometer used to measure specific gravity of milk and scale is limited to the specific gravity of milk. Negative charges keep the proteins repellant from each other hence they do not agglomerate into lumps.

This usually results from using a weak acid, which fails to break the fat globule membrane. Any deviation in temperature from the recommended reading temperature is adjusted by either adding or subtracting accordingly. Acid determination should not be used as the sole basis of accepting or rejecting milk because milk can have acceptable acidity but suffers from flavor defects and other bacterial problems. The butyrometers should be emptied into a special container for the very corrosive liquid of acid-milk, and the butyrometers should be washed in warm water and dried before the next use. Labelling and records keeping Samples must be clearly labelled with name of farmer or code number and records of dates, and places included in standard data sheets.

The Resazurin solution can later be used to test the microbial activity in a given milk sample. Your email address will not be published. This test works on the principle of a dye indicator, novel karya fredy s pdf which changes colour when oxidized. It is determined using two methods a.

This is a simple and quick method used to test the acidity of milk. Butterfat determination is important because it can be used to value the milk for payment purposes and to determine how to standardize the milk.

Simultaneously various enzymes present in milk, and which might affect its flavour, are destroyed. The displaced fluid has equal weight as the floating body. Since the test is accurate and sensitive to added water in milk, it is used to detect whether milk is of normal composition and adulterated. Moreover, its high nutritive value makes it an ideal medium for the rapid multiplication of bacteria, particularly under unhygienic production and storage at ambient temperatures. Let the Lactometer sink slowly into the milk.

Cheese processing also depends on acidity Natural acidity of freshly drawn milk is due to its constituents e. This makes freezing point test the most accurate test for milk adulteration by water addition. How to determine the amount of water in adulterated milk. The result of the test is obtained instantly, and the cost of the test are low.

Look at the can lid and the milk can to check cleanliness. Resazurin is a dye indicator. If a milk sample fails in the test, the milk must contain many acid or rennet producing microrganisms or the milk has an abnormal high percentage of proteins like colostral milk. It is based on the observation of the blue colour imparted in the milk, which will disappear with time.

If there is clotting, coagulation or precipitation, the milk has failed the test. The unknown substance with indicator added to it will match the colour of solutions with known pH. Natural acidity of freshly drawn milk is due to its constituents e.

This test has low correlation with other tests especially those that show presence of bacteria. All the glassware used must be sterile. Store this buffer-substrate solution in a refrigerator and protected against light. Under specified conditions Resazurin is dissolved in distilled boiled water.

This method involves measuring the difference in two different voltages of two electrodes in a sample. It may also result from putting insufficient acid or insufficient mixing of milk and acid. If the milk coagulates, it is an indication that the milk will not be able to withstand processing conditions due to high acidity. Destabilizing these forces will lead to flocculation of the proteins.

If acid production as suspect sample is less than in the normal milk sample, then, the suspect sample contains antibiotics or other inhibitory substances. Acidity test is performed to determine the level of natural or developed acidity in milk. There might be too much acid causing the milk to burn.

The accuracy of this method can be increased by using a comparator which will compensate for the turbidity of the milk. But look to see if there is an unusual sediment from the milk at the bottom of the milk can and taste to find out if the milk is too sweet or salty to be normal. Prepare a blank sample from boiled milk of the same type as that undergoing the test. Boil a small amount of milk in a spoon, test tube or other suitable container. Experiences from Ethiopia.

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