How to Identify Adulterated Feed Ingredients? Practical Identification Methods Shared
How to Identify Adulterated Feed Ingredients?
(Agricultural Wealth Network) How to Identify Adulterated Feed Ingredients?
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I. Soybean cake (meal) has the appearance of light yellow or pale yellow irregular fragments, uniform in color, free from fermentation, mold, caking, insect damage, and off-odors or off-flavors. It is common to find peanut shell powder, fine sand, etc. mixed into soybean meal, which can be detected by water sediment, appearance, and microscopic examination. The degree of raw versus cooked soybean meal affects feeding results; generally, the lighter the color, the rawer the soybean meal and the poorer the feeding results. The pH value can be measured with pH test paper, and a pH value of around 3 is preferable. Further, the urease activity index can be determined, and the measured value must not exceed 0.4. It is often adulterated with mud and sand, 5%-10% stone powder, or crushed corn. The identification methods are as follows:
1. Water soaking method: Take 25 grams of soybean cake (meal), place it in a glass cup containing 250 milliliters of water and soak for 2-3 hours, then gently stir with a wooden stick. If adulterated, layering can be seen, with soybean cake (meal) on top and mud and sand on the bottom.
2. Iodine tincture identification method: Take a small amount of soybean cake (meal) and place it on a clean white porcelain plate, spread it thinly and evenly, and drop a few drops of iodine tincture on it. After 1 minute, if some of the material turns blue-black, it indicates possible adulteration with corn, wheat bran, rice hulls, etc.
3. Raw and cooked soybean cake inspection method: Feed should use cooked soybean cake as a raw material, not raw soybean cake, because raw soybean cake contains substances such as trypsin inhibitor and saponin, which affect feed palatability and digestibility. Take 0.1 grams of urea and place it in a 250-milliliter Erlenmeyer flask, add 0.1 grams of the tested soybean cake powder, add distilled water to 100 milliliters, cover with a stopper, and keep warm in water at 45°C for 1 hour. Take a strip of red litmus paper and immerse it in the Erlenmeyer flask. If the litmus paper turns blue, it indicates the soybean cake is 1-10%. During identification, insert a hand into a pile of wheat bran and then withdraw it. If white powder sticks to the fingers and is not easy to shake off, it indicates adulteration with talcum powder; if it shakes off easily, it is residual flour. Then grab a handful of wheat bran and squeeze hard. If it easily forms a ball, it is wheat bran; if the hand feels swollen when squeezing, it may be adulterated with rice chaff.
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II. Feed corn
The appearance should be neat and uniform kernels, yellow or white in color, free from fermentation, mold, caking, off-odors, and off-flavors, with no other substances mixed in. For new corn, special attention should be paid to whether the moisture content is too high.
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III. Shell powder
Inferior shell powder appears flour-like or crumb-like, generally with a calcium content of about 28%. Good shell powder should contain more than 70% shell pieces the size of sorghum grains and less than 30% fine powder. It is best to choose unprocessed, uncrushed large shells and process them yourself; after crushing, the calcium content should be above 36%36%.
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IV. Bone meal
Good bone meal contains 25% calcium and 13% phosphorus. Adulterated bone meal often has insufficient phosphorus, which can easily cause paralysis in livestock and poultry. Bone meal that has not been degelatinized easily spoils and deteriorates, often causing poisoning in livestock and poultry. Fake bone meal is often adulterated with stone powder, shell powder, fine sand, and other impurities.
1. Visual observation method: Pure bone meal is grayish-white powder or granular, with some particles showing a honeycomb-like structure and giving off its inherent odor; adulterated bone meal has only a few honeycomb-like particles, or none at all, and bone meal adulterated with stone powder or shell powder is whitish in color.
2. Dilute hydrochloric acid dissolution method: Pour bone meal into dilute hydrochloric acid solution. If it is pure bone meal, a short "shasha" sound will be emitted, no bubbles will form on the surface of the bone meal particles, and finally it will all dissolve, with the solution appearing turbid. On the surface of the hydrochloric acid solution of degelatinized bone meal, a very small amount of organic matter floats; for steamed bone meal and raw bone meal, more floating matter appears on the surface; fake bone meal shows none of the above chemical phenomena.
3. Incineration method: Take a small amount of bone meal and place it in a test tube, then hold it over a fire to burn. Pure bone meal produces steam and a pungent smell of burning hair; adulterated bone meal produces less steam and odor; fake bone meal produces no steam or odor; deteriorated bone meal that has not been degelatinized has an off-odor.
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V. Methionine
Some commercially sold methionine has been adulterated with fake starch, glucose powder, stone powder, and other impurities, so that its amino acid content reaches only 50%, far below the national standard.
1. Sensory inspection method: True methionine is pure white or slightly yellowish, lustrous crystals with a slightly sweet taste; fake methionine is yellow or gray, with very few shiny crystals and a strange taste and astringent feeling.
2. Ignition method: Take 1 porcelain crucible and add 1 gram of methionine, carbonize it on an electric furnace, then burn it in a muffle furnace at 55°C for 1 hour. The residue left after burning true methionine should be below 0.5%.
3. Dissolution method: Take a 250-milliliter beaker, add 50 milliliters of distilled water, then add 1 gram of methionine, and stir gently with a glass rod. Fake methionine does not fully dissolve in water, while true methionine almost completely dissolves in water.
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VI. Wheat bran
Common adulterants include talcum powder, rice chaff, etc., generally added at 8%-10%. For identification, the hand-grasping method is mostly used. Insert the hand into the wheat bran and then withdraw it. If much white powder adheres to the fingers and is not easy to shake off, it indicates adulteration with talcum powder; if it shakes off easily, it is residual flour. Then grab a handful of wheat bran and squeeze hard. If the wheat bran easily forms a ball, it is pure wheat bran; if the hand feels swollen when squeezing, it indicates adulteration with rice chaff.
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VII. Calcium hydrogen phosphate
Calcium hydrogen phosphate is a mineral raw material that provides available phosphorus and calcium for poultry and livestock. Its appearance is white powder, bulky in texture, light in specific gravity, fine in particles, and smooth to the touch, with phosphorus content >16.0%, calcium content >21.0%, and fluorine content <0.18%. Adulteration of calcium hydrogen phosphate mainly involves adding stone powder or crushing phosphate rock and then adding stone powder. Due to the many impurities, the appearance color is darker, appearing light orange-red or gray-black, with greater specific gravity and coarser particle size, and a larger granule can be felt in the hand. There are two qualitative identification methods. One is the hydrochloric acid test: place a small amount of sample on a glass watch glass, add a few drops of hydrochloric acid to immerse it. If it vigorously bubbles, it proves that the sample contains stone powder and is counterfeit calcium hydrogen phosphate; if it does not bubble or bubbles only slightly, the sample has not been adulterated with stone powder. The other is the silver nitrate test: place a small amount of sample on a watch glass, add a few drops of silver nitrate. If it all becomes a bright yellow precipitate, it is calcium hydrogen phosphate; if it becomes a light yellow incomplete precipitate, it is not calcium hydrogen phosphate. Phosphate rock that is directly crushed and sold without defluoridation causes the product's fluorine content to seriously exceed the standard, which will seriously affect feed quality and the health of poultry and livestock. The fluorine content in calcium hydrogen phosphate can be quantitatively determined using testing instruments such as ion analyzers and fluorine electrodes.
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I. Soybean cake (meal) has the appearance of light yellow or pale yellow irregular fragments, uniform in color, free from fermentation, mold, caking, insect damage, and off-odors or off-flavors. It is common to find peanut shell powder, fine sand, etc. mixed into soybean meal, which can be detected by water sediment, appearance, and microscopic examination. The degree of raw versus cooked soybean meal affects feeding results; generally, the lighter the color, the rawer the soybean meal and the poorer the feeding results. The pH value can be measured with pH test paper, and a pH value of around 3 is preferable. Further, the urease activity index can be determined, and the measured value must not exceed 0.4. It is often adulterated with mud and sand, 5%-10% stone powder, or crushed corn. The identification methods are as follows:
1. Water soaking method: Take 25 grams of soybean cake (meal), place it in a glass cup containing 250 milliliters of water and soak for 2-3 hours, then gently stir with a wooden stick. If adulterated, layering can be seen, with soybean cake (meal) on top and mud and sand on the bottom.
2. Iodine tincture identification method: Take a small amount of soybean cake (meal) and place it on a clean white porcelain plate, spread it thinly and evenly, and drop a few drops of iodine tincture on it. After 1 minute, if some of the material turns blue-black, it indicates possible adulteration with corn, wheat bran, rice hulls, etc.
3. Raw and cooked soybean cake inspection method: Feed should use cooked soybean cake as a raw material, not raw soybean cake, because raw soybean cake contains substances such as trypsin inhibitor and saponin, which affect feed palatability and digestibility. Take 0.1 grams of urea and place it in a 250-milliliter Erlenmeyer flask, add 0.1 grams of the tested soybean cake powder, add distilled water to 100 milliliters, cover with a stopper, and keep warm in water at 45°C for 1 hour. Take a strip of red litmus paper and immerse it in the Erlenmeyer flask. If the litmus paper turns blue, it indicates the soybean cake is 1-10%. During identification, insert a hand into a pile of wheat bran and then withdraw it. If white powder sticks to the fingers and is not easy to shake off, it indicates adulteration with talcum powder; if it shakes off easily, it is residual flour. Then grab a handful of wheat bran and squeeze hard. If it easily forms a ball, it is wheat bran; if the hand feels swollen when squeezing, it may be adulterated with rice chaff.
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II. Feed corn
The appearance should be neat and uniform kernels, yellow or white in color, free from fermentation, mold, caking, off-odors, and off-flavors, with no other substances mixed in. For new corn, special attention should be paid to whether the moisture content is too high.
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III. Shell powder
Inferior shell powder appears flour-like or crumb-like, generally with a calcium content of about 28%. Good shell powder should contain more than 70% shell pieces the size of sorghum grains and less than 30% fine powder. It is best to choose unprocessed, uncrushed large shells and process them yourself; after crushing, the calcium content should be above 36%36%.
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IV. Bone meal
Good bone meal contains 25% calcium and 13% phosphorus. Adulterated bone meal often has insufficient phosphorus, which can easily cause paralysis in livestock and poultry. Bone meal that has not been degelatinized easily spoils and deteriorates, often causing poisoning in livestock and poultry. Fake bone meal is often adulterated with stone powder, shell powder, fine sand, and other impurities.
1. Visual observation method: Pure bone meal is grayish-white powder or granular, with some particles showing a honeycomb-like structure and giving off its inherent odor; adulterated bone meal has only a few honeycomb-like particles, or none at all, and bone meal adulterated with stone powder or shell powder is whitish in color.
2. Dilute hydrochloric acid dissolution method: Pour bone meal into dilute hydrochloric acid solution. If it is pure bone meal, a short "shasha" sound will be emitted, no bubbles will form on the surface of the bone meal particles, and finally it will all dissolve, with the solution appearing turbid. On the surface of the hydrochloric acid solution of degelatinized bone meal, a very small amount of organic matter floats; for steamed bone meal and raw bone meal, more floating matter appears on the surface; fake bone meal shows none of the above chemical phenomena.
3. Incineration method: Take a small amount of bone meal and place it in a test tube, then hold it over a fire to burn. Pure bone meal produces steam and a pungent smell of burning hair; adulterated bone meal produces less steam and odor; fake bone meal produces no steam or odor; deteriorated bone meal that has not been degelatinized has an off-odor.
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V. Methionine
Some commercially sold methionine has been adulterated with fake starch, glucose powder, stone powder, and other impurities, so that its amino acid content reaches only 50%, far below the national standard.
1. Sensory inspection method: True methionine is pure white or slightly yellowish, lustrous crystals with a slightly sweet taste; fake methionine is yellow or gray, with very few shiny crystals and a strange taste and astringent feeling.
2. Ignition method: Take 1 porcelain crucible and add 1 gram of methionine, carbonize it on an electric furnace, then burn it in a muffle furnace at 55°C for 1 hour. The residue left after burning true methionine should be below 0.5%.
3. Dissolution method: Take a 250-milliliter beaker, add 50 milliliters of distilled water, then add 1 gram of methionine, and stir gently with a glass rod. Fake methionine does not fully dissolve in water, while true methionine almost completely dissolves in water.
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VI. Wheat bran
Common adulterants include talcum powder, rice chaff, etc., generally added at 8%-10%. For identification, the hand-grasping method is mostly used. Insert the hand into the wheat bran and then withdraw it. If much white powder adheres to the fingers and is not easy to shake off, it indicates adulteration with talcum powder; if it shakes off easily, it is residual flour. Then grab a handful of wheat bran and squeeze hard. If the wheat bran easily forms a ball, it is pure wheat bran; if the hand feels swollen when squeezing, it indicates adulteration with rice chaff.
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VII. Calcium hydrogen phosphate
Calcium hydrogen phosphate is a mineral raw material that provides available phosphorus and calcium for poultry and livestock. Its appearance is white powder, bulky in texture, light in specific gravity, fine in particles, and smooth to the touch, with phosphorus content >16.0%, calcium content >21.0%, and fluorine content <0.18%. Adulteration of calcium hydrogen phosphate mainly involves adding stone powder or crushing phosphate rock and then adding stone powder. Due to the many impurities, the appearance color is darker, appearing light orange-red or gray-black, with greater specific gravity and coarser particle size, and a larger granule can be felt in the hand. There are two qualitative identification methods. One is the hydrochloric acid test: place a small amount of sample on a glass watch glass, add a few drops of hydrochloric acid to immerse it. If it vigorously bubbles, it proves that the sample contains stone powder and is counterfeit calcium hydrogen phosphate; if it does not bubble or bubbles only slightly, the sample has not been adulterated with stone powder. The other is the silver nitrate test: place a small amount of sample on a watch glass, add a few drops of silver nitrate. If it all becomes a bright yellow precipitate, it is calcium hydrogen phosphate; if it becomes a light yellow incomplete precipitate, it is not calcium hydrogen phosphate. Phosphate rock that is directly crushed and sold without defluoridation causes the product's fluorine content to seriously exceed the standard, which will seriously affect feed quality and the health of poultry and livestock. The fluorine content in calcium hydrogen phosphate can be quantitatively determined using testing instruments such as ion analyzers and fluorine electrodes.