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Learn about the 4 types of Halal meat tests: Physical, Biochemical, Molecular, Slaughtered/Dead tests. Understand importance of Glycogen Test in differentiating Halal and Haram meats. Methods like Brautigam and Edelmann’s are explained.
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Halal (حلال, ḥalāl, Halaal) is an Arabic term designating which is widely used to designate food seen as permissible according to Islamic ٍ law (Sharia) - (الشريعة الإسلامية). It is the opposite of haraam. It is estimated that 70% of Muslims worldwide follow halal food standards.
HALAL MEAT CERTIFICATION TESTS It involves 4 types of test. Physical tests Biochemical tests Molecular tests Slaughtered or Dead tests
Physical testsPhysical Differentiation of Halal And Haram Meats
Glycogen Test of Meat Objective/Introduction • It is particularly abundant in horse meat and foetal flesh • Glycogen is a reserve polysaccharide in the carbohydrate metabolism of animals. • Main store houses of glycogen in animal body are liver but it is present in very small varying amounts in muscles • animal tissue particularly in liver (4-8%) • muscles 0.5-1%. • As the glycogen is present in much higher amounts in horseflesh and foetal flesh • it is done mainly to differentiate horse and foetal flesh.
Important Features • It is doubtful that whether consumption of the flesh of unborn or stillborn calves would be prejudicial to health, but the sale of such flesh is unjustifiable for the following reasons: • Consumption of flesh of unborn animals is repugnant to the most of the civilized races. • To prevent the entry of Brucella abortis in a human system. • A proportion of cow suffering from tuberculosis metritis give birth to stillborn calves effected with congenital tuberculosis. So, the flesh of foetal or stillborn calves must be condemned
Principle of Glycogen Test • Iodine solution forms an adsorption complex with glycogen molecule, and this adsorption complex is responsible for the appearance of colour. Intensity of colour depends upon the strength of that complex. • Complicated branching of glycogen imparts dark brown or wine red color with iodine. • Straight glycogen molecules gives blue colour with iodine. • Methods for Glycogen Test • For this test it is important to extract glycogen from sample by causing the • decomposition of fibers and precipitation of proteins by treating with boiling water, KOH, and certain other reagents. Some important methods for glycogen test are:
Brautigam and Edelmann’s Method • Apparatus and Reagents • Meat • Distilled water • Burner • Nitric acid • Filter • Saturated aquous solution of iodine or the reagent containing 2 part iodine, 4 parts of KI and 100 parts of water. • Beakers • Pipettes
Procedure • Take 50g of finely divided meat. • Add 200cc of water and boil for ½ hrs. • After cooling, dilute nitric acid is added to the broth to precipitate the protein and to decolorize it. • The broth is filtered. • The portion of the filtrate is treated with freshly prepared saturated aquous solution of iodine or the reagent (2 part iodine +4 part pot.iodide +100 part water) being carefully added so as not to be mixed with broth, but form a layer above it.
Result • Glycogen presence = wine coloured ring at the junction of two layers which disappears on heating and reappears on cooling the tube. • If the colour is not apparent clearly, the chopped meat is heated on water bath with a solution of KOH (3% of wt of flesh) till the fiber is decomposed, then broth is conc. To half its volume treated with nitric acid to precipitate the protein, filtered and treated with iodine. • Conclusions • It is only applied on horse flesh but never in case of flesh of ox, , sheep, pig, dog or cat. It could detect as little as 5% of horse flesh in a mixture. • Drawbacks • Dextrinsdrived from starch also give the same colouration as given by glycogen on reaction with iodine.
Bastien’s Method • Bastien made slight modifications in the previous method and get the most satisfactory result capable of detecting 5% of horse flesh even in the presence of starch. • Apparatus and Reagents • 20gm sausage • Water • Burner • Filter • Iodine water or reagent containing 1gm iodine, 2 gm of pot. Iodide and 100 cc of water • Pipettes • Beakers • Dropper
Procedure • Take 20 gm of finely divided sausage. • Add 100 cc of water. • Boil for 30 minutes to one hour ,so that the volume of the liquid is reduced to about 30 cc. • When cold, the broth is filtered. • About 10 cc of broth is treated with 2 or 3 drops of iodine water, or of a solution of iodine (1 gm iodine, 2 gm of pot. iodide, 100 cc of water ). • Result • A fugitive reddish-violet colour is obtained with horse flesh. When starch is present, acetic acid is added.
If minced meat available then the following tests are done to differentiate the halal and haram meats. • ELISA • Elisa Kits are available that tell about the halal and haram meat. • PCR • This test kits also available in the market that tell about the haram and halal meat.
Malachite green test for the efficiency of bleeding Principle • The test is based upon the principle that oxidized haemoglobin on addition of acidic solution of malachite green produces a green coloured complex. Procedure • 0.7 ml of clear meat extract is taken in an agglutination tube. • To it one drop of acid malachite green solution is mixed. • After mixing, 1 drop of hydrogen peroxide is added and tube is shook till foam develops. • The tube is allowed to stand for 20 minutes for the development of colour. Result • A clear blue colour indicates normal bleeding. • Cloudy and green colour reaction shows imperfect bleeding. • While as a cloudy fluid of olive green colour shows very unsatisfactory bleeding (emergency slaughter of dead animal).
Resazurin test to determine the suitability for human consumption • Four resazurin tablets are dissolved in 100 ml of water. • Filter paper strips are dipped in the above solution and dried in dark and cool room. • For testing, strip is moistened and the piece of meat to be tested is placed on it for one minute. • The strip is then removed and placed on a polythene bag and is kept in a dark room (22-23Cº). • Time taken for the blue colour of the paper to change to red is noted . Result • 10 minutes meat is not acceptable • 10-30 minutes may be acceptable • 30-60 minutes good quality • over 60 minutes very good quality
