Quick test for some adulterants in foods: Milk, Honey, Vegetables, Food Oil, Deshi Ghee

First Published in May 2016                       Edited & Updated on 9 August 2021

Food adulteration (adulteration of foods)

Food adulteration is an increasing threat that dishonest traders and manufacturer all over the world. It gives a way to exploit naive customers and make easy and fast money. In all free market societies where legal control is poor or nonexistent with respect to monitoring of food high quality by regulators, the usage of adulterants is widespread and common. So, the strict application of appropriate laws by the Government authorities and awareness of consumers is very important to eliminate this man-made curse from the society. Here, we are going to discuss a few easy tips to help you examine some of the most important foods at home so that you can avoid food adulteration.

Adulteration in Milk
Among all food items, adulteration in milk is the most frequent one. Milk can be adulterated by mixing simple water with it. Pure milk undergoes some new physical and nutritional constituents when water added to it. If it is impure and contaminated water is added to milk, it makes high risk of being infected by microbial contamination after consumption.

Addition of water is quickly recognisable by users as the milk becomes watery and thin. Adulterers mix various kinds of chemical substances to make milk thick and consistent and to resemble like pure milk. For this purpose they adulterate milk with urea, formalin, vanaspati, starchy foods etc.

Test for adulteration in milk can be done at home using following ways:

  • Reduction Test
    Boil milk on slow heat for 2-3 hours till it solidifies and become hard (khoya). Rough remains indicate the milk is adulterated while oily remains indicate it is excellent.
  • How to identify Water
    Water in milk may not be bad to improve your overall wellness but definitely for your pocket. To evaluate, put a drop of milk on slope surface and let it drift downward If the milk leaves a trail behind, it’s not pure.
  • How to identify Vanaspati/Dalda
    Vanaspati is negative for wellness if consumed in big quantity. To see if milk is adulterated with vanaspati, add 2 tablespoons of hydrochloric acid and 1 tablespoon of sugar to 1 tablespoon of milk. If the mix changes red, it is contaminated.
  • How to identify Starch
    If your vendor has included starchy foods to milk, you can identify it by adding 2 tablespoons to salt (iodine) to 5 ml of milk. Combination will turn red if dairy is adulterated else it remains intact.
  • How to identify Formalin
    Pure milk is spoiled on keeping at 70 degrees within a day. So artificial harmful preservatives (formalin etc.) are included to improve the life expectancy of the adulterated item. But it is a highly toxic substance, and harmful for kidney and liver.To evaluate for formalin existence in milk, take 10 ml of it in test tube and put 2-3 drops of sulphuric acid into it. If a blue ring appears at the top, dairy is adulterated else not.
  • How to identify for urea
    One of the most frequent form of adulteration in dairy is combining of urea since it doesn’t changes the flavour and is little difficult to identify. To evaluate for urea in dairy, mix half tablespoon of dairy and soyabean (or arhar) powder together and shake well. After 5 minutes, dip litmus paper for 30 seconds and if there is a shade consist of red to blue it indicates the dairy has urea in it.
  • How examine Artificial Milk
    Synthetic dairy is produced by combining chemicals and things like soap in natural dairy. Artificial dairy can simply be identified by bad flavor. It feels soapy when rubbed and changes yellowish when heated.

Adulteration analyze in Honey
The common ingredients usually included with honey as adulterants are: Glucose syrup, bananas, rice or maize flour syrup, and sweet potato. These adulterants are usually included with honey independently or together by some honey vendors to make more profit. The following tests are  necessary to recognize pure and adulterated honey.

  • Flame Test
    Pure honey provided smoke free fire when captivated using candlestick fire or lab Bunsen burning. Existence of adulterants was verified by viewing smoky fire and/or breaking sound during fire test.
  • Warming Effect
    This test is done upon tender heating of honey  to melt frozen material.
    Pure honey dissolves to clear viscous  mixture, while wax components stay on the surface.
  • The blending of honey with bananas,  potato-starch or wheat flour to dissolve to make non-transparent and dispersed liquid.Mixing of honey with sugar (more than 50 % w/w) is done to make made  partially transparent, more dispersed and thicker form.
  • Adulteration of honey with sugar, banana or other substances  is exposed when microscopic analysis  is done. Plant tissues and fibers will be observed after the test if honey is adulterated

Adulteration in Clean vegetables
Like Green Chilli and Bitter Gourd and others

  • Test by blotting paper
    Very first we are going to inform the many methods by that you can recognize the adulteration in green vegetables. Almost all fresh vegetables looks green. So, Malachite green is used to mislead it as fresh.
    For checking its wholesomeness you can remove some veggies for place and sample it on a bit of moistened white colored blotting pieces of paper. The impact of color on the paper suggests the usage of malachite green or any other low priced synthetic color.
  • Test by soaked cotton
    Have a patch of pure cotton soaked in wax Paraffin and rub it on vegetables. You must understand that artificial colors were used for making it look fresh if the green color comes from the vegetable. If you want to know the purity of tomato then you can apply the same method and if they were colored then you will find red color coming from it. Similarly, Likewise, you  can test the freshness of red-colored chillies also.

Adulteration in Mustard Oil
Oils are produced from various plants and fish. Oils are not actually taken as a item of food group, but they contribute essential nutrients in our daily consumption. They are used to cook, fry prepare every-day diets and we call it edible oil. Some of common edible oils are: vegetable oil, safflower oil, olive oil, corn oil, soybean oil, cottonseed oil  and mustard oil. Two major adulteration process commonly found in edible oils, are: 1) admixing cold press oil with refined one and 2) replacement of costlier oils with cheaper one.
Mustard oil is highly popular within the Indian Subcontinent as edible oil.
We will discuss here about adulteration test in mustard oil. The biggest reason is that the production of mustard oil is very less as compared to high consumption. In quest for increased profit argemone oil, castor oil, mineral oil, organic oil and even mobile oil are blended with mustard oil.

  • How to detect Aargemone oil
    Go on a small volume of oil in a test tube. Add equal quantity of concentrated Nitric acid and shake it carefully. Reddish colored to reddish dark brown shade in lower (acid solution) level would indicate the presence of Argemone oil. Colorless (not yellowish) Nitric acid may be used. If artificial color presents , it will usually be a bright shade of color. The test might often give deceptive. The test may not respond if the Argemone oil is present in small quantity.
  • How you can identify Mineral oil
    Get 2 ml from the oil sample and add more an identical quantity of N/2 Alcoholic potash. Warmth in cooking water bath tub (drop in boiling hot normal water) for about 15 minutes and include 10 ml of water. Any turbidity shows reputation of vitamin oil. If mineral oil is present in small quantity, this test may not be positive.
  • The best way to detect Castor oil
    Get about 1 ml of the oil; add more 10 ml of acidified petroleum ether and mixture well. Include a number of drops of ammonium molybdate reagent. Immediate appearance of bright white turbidity suggests the presence of castor oils. If castor oil is present in small quantity, this test may not be positive.

Adulteration test in deshi Ghee

Ghee can simply be admixture with inexpensive adulteration. This typical adulterants are the (i) Vanaspati (hydrogenated fat), (ii) Refined veggie oil (Deoxidized oils) example – groundnut, grape, pure cotton seeds oil (iii) fats of animal body. As vanaspati is added with sesamum oil and it has been become almost compulsory, the detection of adulteration of ghee also becomes complicated. So, the peoples of all walks of life should think over it seriously. The adulteration in ghee can be detected by using following two tests. (i) Furfural test (ii) Baudouin test.

  • Furfural test:
    Take 100 ml of dissolved ghee in the test tube. In another test mix 0.1 ml of the furfural liquid with 10 ml conc. HCL. Mix the dissolved ghee with the furfural acid solution. Shake well, allow the mix to stand for 10 min. and observe the color. If ghee is adulterated with sesamum oil, violet color will be appeared there.
  • Baudoduim test:
    Mix 0.1 gm of perfectly powdered cane sugar with 10 ml conc. Hcl.  Add this mixture for about 10 ml of dissolved ghee. Melt thoroughly and allow standing for 10 min. If violet color seems to be, add 10 ml water, shake and allow standing for another 10 min. Appearance of violet color indicates the existence of sesamum oil.

Follow above steps to test food to insure we are stay healthy and young.

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