How to identify adulteration of feed materials?

(agricultural Wealth Network) how to identify adulteration of feed materials? First, the appearance of soybean cake (meal) is light yellow or light yellow irregular fragments, the color is the same, no fermentation, mildew, caking, moth and peculiar smell. Common directed soybean meal mixed with peanut shell powder, fine sand, etc., can be detected by water precipitate, appearance, microscopic examination and so on. The raw and mature degree of soybean meal affects the feeding effect. The lighter the color is, the worse the feeding effect is. The pH value can be measured by pH test paper, and the better pH value is 3. Furthermore, it can be used to determine the index of urease activity, and the measured value should not exceed 0.4. Often mixed with sediment, 5% Mel 10% stone powder or chopped corn. The identification methods are as follows: 1. Take 25 grams of soybean cake (meal) by water immersion, soak it in a glass cup containing 250 ml of water for 2-3 hours, then stir it gently with a wooden stick. If adulterated, you can see that the upper layer is soybean cake (meal) and the lower layer is sediment. 2, iodine identification method to take a little soybean cake (meal) on a clean white porcelain plate, spread thin, drop a few drops of iodine on it, 1 minute later, if some of the substances become blue-black, indicating that it may be mixed with corn, wheat bran, rice husk and so on. 3. Raw and cooked bean cake examination method: raw soybean cake is used as raw material instead of raw bean cake, because raw bean cake contains antitrypsin, saponin and other substances, which affect the palatability and digestibility of feed. Put 0.1g urea in 250ml triangle flask, add 0.1g bean cake powder to be tested, add distilled water to 100ml, cover with bottle cork and heat in 45 ℃ water for 1 hour. Take a piece of red litmus test paper and dip it into a triangular flask. If the litmus test paper turns blue, it means that the bean cake is 1: 10%. When identifying, insert the hand into a pile of wheat bran and pull it out. If there is white powder on the fingers and it is not easy to shake off, it is mixed with talc powder. If it is easy to shake off, it is residual flour. Then grab a handful of bran with your hands and hold it hard. If it is easy to form a ball, it is bran; if you have a feeling of rising in your hand, it may be mixed with rice bran. Second, the appearance of corn for feed should be neat, uniform, yellow or white in color, no fermentation, mildew, caking, peculiar smell, and no infiltration of other substances. New corn should pay special attention to whether the moisture is too high. -the shell powder generally contains about 28% calcium. Good shell powder should contain more than 70% of the shells the size of sorghum grains and less than 30% of the broken noodles. It is best to choose unprocessed and crushed large shells and process them by yourself. after crushing, the calcium content should be more than 36%. Good bone meal contains 25% calcium and 13% phosphorus. Adulterated bone meal often contains insufficient phosphorus, which can easily cause paralysis of livestock and poultry. Undegummed bone meal is prone to decay and deterioration, which often causes poisoning in livestock and poultry. Artificial bone powder is often mixed with stone powder, shell powder, fine sand and other sundries. The main results are as follows: 1. Naked eye observation: pure bone powder is grayish white powder or granular, some particles are honeycomb, emitting inherent smell; adulterated bone powder has only a few honeycomb particles, or no honeycomb particles, stone powder, shell powder bone powder color white. 2. if the bone powder is poured into the dilute hydrochloric acid solution by dilute hydrochloric acid solution, if it is pure bone powder, there will be a short-term "rustling" sound, there are no air bubbles on the surface of bone powder particles, and finally all of them are dissolved, and the solution is turbid. There is a very small amount of organic matter floating on the surface of the hydrochloric acid solution of degummed bone powder, and there are more floating substances on the surface of steamed bone powder and raw bone powder, and there is no above chemical phenomenon in false bone powder. 3. In the incineration method, a little bone powder is put into the test tube and burned on the fire. The pure bone powder produces steam and produces a pungent smell of singeing hair, while the adulterated bone powder produces less steam and smell; the false bone powder has no steam and smell; the undegummed metamorphic bone powder has a peculiar smell. Methionine some marketed methionine contains only 50% amino acid due to the addition of false starch, glucose powder, stone powder and other sundries, which is much lower than the national standard. 1. Sensory examination: true methionine is pure white or yellowish, glossy crystal, slightly sweet taste; fake yellow or gray, very few flash crystals, strange taste and astringent feeling. 2. Take a porcelain crucible with 1 gram of methionine, carbonize it in an electric furnace, and then burn it on a 55 ℃ Maofu furnace for 1 hour. After burning, the residue of true methionine should be less than 0.5%. 3. Dissolve a 250ml beaker, add 50 ml distilled water, then add 1 gram of methionine, stir gently with a glass stick, pseudo-methionine is not completely soluble in water, while true methionine is almost completely soluble in water. -- 6. Common adulterants of wheat bran include talc powder, rice bran, etc., with a general adulteration amount of 8% to 10%. When identifying, use the hand grip method, insert the hand into the wheat bran, and then pull it out. If there is a lot of white powder on the finger, and it is not easy to shake off, it means that it is mixed with talc powder, if it is easy to shake off, it is residual flour. Then grab a handful of bran with your hand and hold it hard. If the bran is easy to form a ball, it is pure bran. If you have a rising feeling in your hand, it means you have rice chaff. Calcium hydrogen phosphate is a mineral raw material that provides available phosphorus and calcium for livestock. The appearance is white powder, the texture is loose, the specific gravity is light, the particle is fine, the feel is delicate, the phosphorus content is more than 16.0%, the calcium content is more than 21.0%, and the fluorine content is < 0.18%. Calcium hydrogen phosphate adulteration is mainly mixed with stone powder or crushed phosphate rock to add stone powder, because of many impurities, dark appearance, light orange or grayish black, large specific gravity, coarse particle size, you can feel the existence of larger particles. There are two qualitative identification methods, one is hydrochloric acid test, put a few samples on the glass surface plate, add a few drops of hydrochloric acid immersion, such as violent bubbles, it is proved that there is stone powder in the sample, which is fake calcium hydrogen phosphate, if there is no blistering or slight blistering, the sample is not mixed with stone powder. The other is silver nitrate test, put a few samples on the surface plate, add a few drops of silver nitrate, if all become bright yellow precipitation, it is calcium hydrogen phosphate, if it becomes light yellow incomplete precipitation, it is not calcium hydrogen phosphate. The phosphate rock is crushed and sold directly without defluorination, which makes the fluorine content of the product seriously exceed the standard, which will seriously affect the feed quality and livestock health. The fluorine content in calcium hydrogen phosphate can be quantitatively determined by ion analyzer, fluorine electrode and other detection instruments.