Common Adulterants/Contaminantsin food and Simple screening tests for their detection

           Adulteration in food is normally present in its most crude form, prohibited substances are either added or partly or wholly substituted.  In India normally the contamination/adulteration in food is done either for financial gain or due to carelessness and lack in proper hygienic condition of processing, storing, transportation and marketing. This ultimately results that the consumer is either cheated or often become victim of diseases. Such types of adulteration are quite common in developing countries or backward countries. However, adequate precautions taken by the consumer at the time of purchase of such produce can make him alert to avoid procurement of such food. It is equally important for the consumer to know the common adulterants and their effect on health. 

Injurious Adulterants/Contaminants in Foods and their Health Effects S.No Adulterant Foods Commonly

InvolvedDiseases or Health

EffectsAdulterants in food

1 Argemone seedsArgemone oil

Mustard seedsEdible oils and fats

Epidemic dropsy,Glaucoma,Cardiac arrest

2 Artificially coloured foreign seeds

As a substitute for cumin seed,Poppy seed, black pepper

Injurious to health

3 Foreign leaves or exhausted tea leaves, saw dust artificially coloured

Tea Injurious to health, cancer

4 TCP Oils Paralysis5 Rancid oil Oils Destroys vitamin A and E6 Sand, marble chips, stones,

filthFood grains, pulses etc. Damage digestive tract

7 Lathyrus sativus Khesari dal alone orMixed in other pulses

Lathyrism (crippling spastic paraplegia)

Chemical Contamination8 Mineral oil (white oil,

petroleum fractions)Edible oils and fats,Black pepper

Cancer

9 Lead  chromate Turmeric whole and powdered, mixed spices

Anemia, abortion, paralysis, brain damage

10 Methanol Alcoholic liquors Blurred vision, blindness, death

11 Arsenic Fruits such as apples sprayed over with lead arsenate

Dizziness, chills, cramps, paralysis, death

12 Barium Foods contaminated by rat poisons (Barium  carbonate)

Violent peristalisis, arterial hypertension, muscular twitching, convulsions, cardiac disturbances

13 Cadmium Fruit juices, soft drinks, etc. in contact with cadmium plated vessels or equipment. Cadmium contaminated water and shell-fish

‘Itai-itai (ouch-ouch) disease, Increased salivation, acute gastritis, liver and kidney damage, prostrate cancer

14 Cobalt Water, liquors Cardiac insufficiency and mycocardial failure

15 Lead Water, natural and processed food

Lead poisoning (foot-drop, insomnia, anemia, constipation, mental

retardation, brain damage)

16 Copper Food Vomiting, diarrhoea17 Tin Food Colic, vomiting18 Zinc Food Colic, vomiting19 Mercury Mercury fungicide treated

seed grains or mercury contaminated fish

Brain damage, paralysis, death

NOTE : Safe limits have been prescribed for above metals in different food. Continuous use of food contaminated with these metals beyond safe limits may cause these diseases

Bacterial contamination20 Bacillus cereus Cereal products, custards,

puddings, saucesFood infection (nausea, vomiting, abdominal pain, diarrhoea)

21 Salmonella spp. Meat and meat products, raw vegetables, salads, shell-fish, eggs and egg products, warmed-up leftovers

Salmonellosis (food infection usually with fever and chills)

22 Shigella sonnei Milk, potato, beans, poultry, tuna, shrimp, moist mixed foods

Shigellosis (bacillary dysentery)

23 Staphylococcus aureusEntero-toxins-A,B,C,D or E

Dairy products, baked foods especially custard or cream-filled foods, meat and meat products, low-acid frozen foods, salads, cream sauces, etc.

Increased salivation, vomiting, abdominal cramp, diarrhoea, severe thirst, cold sweats, prostration

24 Clostridium botulinus toxinsA,B,E or F

Defectively canned low or medium-acid foods; meats, sausages, smoked vacuum-packed fish, fermented food etc.

Botulism (double vision, muscular paralysis, death due to respiratory failure)

25 Clostridium.perfringens(Welchii) type A

Milk improperly processed or canned meats, fish and gravy stocks

Nausea, abdominal pains, diarrhoea, gas formation

26 Diethyl stilbestrol (additive in animal feed)

Meat Sterlites, fibroid tumors etc.

27 3,4 Benzopyrene Skoked food Cancer28 Excessive solvent residue Solvent extracted oil, oil cake

etc.Carcinogenic effect

29 Non-food grade or contaminated packing material

Food Blood clot, angiosarcoma, cancer etc.

30 Non-permitted colour or permitted food colour beyond safe limit

Coloured food Mental retardation, cancer and other toxic effect.

31 BHA and BHT beyond safe limit

Oils and fats Allergy, liver damage, increase in serum chloresterol etc.

32 Monosodium glutamate(flour) (beyond safe limit)

Chinese food, meat and meat products

Brain damage, mental retardation in infants

33 Coumarin and dihydro coumarin

Flavoured food Blood anticoagulant

34 Food flavours beyond safe limit

Flavoured food Chances of liver cancer

35 Brominated vegetable oils Cold drinks Anemia, enlargement of heart

36 Sulphur dioxide and sulphite beyond safe limit

In variety of food as preservative

Acute irritation of the gastro-intestinal tracts etc.

37 Artificial sweetners beyond safe limit

Sweet foods Chances of cancer

Fungal contamination38 Aflatoxins Aspergillus flavus-

contaminated foods such as groundnuts, cottonseed, etc.

Liver damage and cancer

39 Ergot alkaloids from Claviceps purpurea Toxic alkaloids, ergotamine, ergotoxin and ergometrine groups

Ergot-infested bajra, rye meal or bread

Ergotism (St.Anthony’s fire-burning sensation in extremities, itching of skin, peripheral gangrene)

40 Toxins fromFusarium sporotrichioides

Grains (millet, wheat, oats, rye,etc)

Alimentary toxic aleukia(ATA) (epidemic panmyelotoxicosis)

41 Toxins from Fusarium sporotrichiella

Moist grains Urov disease (Kaschin-Beck disease)

42 Toxins fromPenicillium inslandicumPenicillium atricum,Penicillium citreovirede,Fusarium, Rhizopus,Aspergillus

Yellow rice Toxic mouldy rice disease

43 Sterigmatocystin fromAspergillus versicolourAspergillus nidulans and bipolaris

Foodgrains Hepatitis

44 Ascaris lumbricoides Any  raw food or water contaminated by human faces containing eggs of the parasite

Ascariasis

45 Entamoeba histolyticaViral

Raw vegetables and fruits Amoebic dysentery

46 Virus of infectiousHepatitis (virus A)

Shell-fish, milk, unheated foods contaminated with faeces, urine and blood of infected human

Infectious hepatitis

47 Machupo virus Foods contaminated with rodents urine, such as cereals

Bolivian haemorrhagic fever

Natural Contamination48 Flouride Drinking water, sea foods,

tea, etc.Excess fluoride causes fluorosis (mottling of teeth, skeletal  and neurological disorders)

49 Oxalic acid Spinach, amaranth, etc. Renal calculi, cramps, failure of blood to clot

50 Gossypol Cottonseed flour and cake Cancer51 Cyanogenetic compounds Bitter almonds, apple seeds,

cassava, some beans etc.Gastro-intestinal disturbances

52 Polycyclic AromaticHydrocarbons(PAH)

Smoked fish, meat, mineral oil-contaminated water, oils, fats and fish, especially shell-fish

Cancer

53 Phalloidine (Alkaloid) Toxic mushrooms Mushroom poisoning

(Hypoglycemia, convulsions, profuse watery stools, severe necrosis of liver leading to hepatic failure and death)

54 Solanine Potatoes Solanine poisoning (vomiting, abdominal pain, diarrhoea)

55 Nitrates and Nitrites Drinking water, spinach rhubarb, asparagus, etc. and meat products

Methaemoglobinaemia especially in infants, cancer and tumours in the liver, kidney, trachea oesophagus and lungs. The liver is the initial site but afterwards tumours appear in other organs.

56 Asbestos (may be present  intalc, Kaolin, etc. and in processed foods)

Polished rice, pulses, processed foods containing anti-caking agents, etc.

Absorption in particulate form by the body may produce cancer

57 Pesticide residues (beyond safe limit)

All types of food Acute or chronic poisoning with damage to nerves and vital organs like liver, kidney, etc.

58 Antibiotics (beyond safe limit) Meats from antibiotic-fed animals

Multiple drug resistance hardening of arteries, heart disease

 

 

   

       

  

 

     

  

   

 

 

       

 

      

 

 

  In the following table simple screening tests for detection of adulteration in common foods

have been prescribed. These tests give idea of presence of adulteration. However, conformation for these adulterations is normally made through laboratory tests.

Detection Kit    

     

Simple Screening test for Detecting Adulteration in Common Food 

S.No Food article Adulteration Test1 Vegetable oil Castor oil Take 1 ml. of oil in a clean dry test tube. Add 10 ml.

Of acidified petroleum ether. Shake vigorously for 2 minutes. Add 1 drop of Ammonium Molybdate reagent. The formation of turbidity indicates presence of Castor oil in the sample.

Argemone oil Add 5 ml, conc. HNO3 to 5 ml.sample. Shake carefully. Allow to separate yellow, orange yellow, crimson colour in the lower acid layer indicates adulteration.

2 Ghee Mashed PotatoSweet Potato, etc.

Boil 5 ml. Of the sample in a test tube. Cool and a drop of iodine solution. Blue colour indicates presence of Starch. colour disappears on boiling &  reappears on cooling.

Vanaspati Take 5 ml. Of the sample in a test tube. Add 5 ml. Of Hydrochloric acid and 0.4 ml of 2% furfural solution or sugar crystals. Insert the glass stopper and shake for 2 minutes. Development of a pink or red colour indicates presence of Vanaspati in Ghee.

Rancid stuff (old ghee)

Take one teaspoon of melted sample and 5 ml. Of HCl in a stoppered glass tube. Shake vigorously for 30 seconds. Add 5 ml. Of 0.1% of ether solution of Phloroglucinol. Restopper & shake for 30 seconds and allow to stand for 10 minutes. A pink or red colour in the lower(acid layer) indicates rancidity.

Synthetic Colouring Matter

Pour 2 gms. Of filtered fat dissolved in ether. Divide into 2 portions. Add 1 ml. Of HCl to one tube. Add 1 ml. Of 10% NaOH to the other tube. Shake well and allow to stand. Presence of pink colour in acidic solution or yellow colour in alkaline solution indicates added colouring matter.

3 Honey Invert sugar/jaggery

1.      Fiehe’s Test: Add 5 ml. Of solvent ether to 5 ml. Of honey. Shake well and decant the ether layer in a petri dish. Evaporate completely by blowing the ether layer. Add 2 to 3 ml. Of resorcinol (1 gm. Of resorcinol resublimed in 5 ml. Of conc. HCl.) Appearance of cherry red colour indicates presence of sugar/jaggery.

2.      Aniline Chloride Test : Take 5 ml. Of honey in a porcelain dish. Add Aniline Chloride solution (3 ml of  Aniline and 7 ml. Of 1:3 HCl) and stir well. Orange red colour indicates presence of sugar.

4. Pulses/Besan Kesari Add 50 ml. Of dil.HCl to a small quantity of dal and

dal(Lathyrus sativus)

keep on simmering water for about 15 minutes. The pink colour, if developed indicates the presence of Kesari dal.

5 Pulses Metanil Yellow(dye)

Add conc.HCl to a small quantity of dal in a little amount of water. Immediate development of pink colour indicates the presence of metanil yellow and similar colour dyes.

Lead Chromate Shake 5 gm. Of pulse with 5 ml. Of water and add a few drops of HCl. Pink colour indicates Lead Chromate.

6 Bajra Ergot infested Bajra

Swollen and black Ergot infested grains will turn light in weight and will float also in water

7 Wheat flour Excessive sand & dirt

Shake a little quantity of sample with about 10 ml. Of Carbon tetra chloride and allow to stand. Grit and sandy matter will collect at the bottom.

Excessive bran Sprinkle on water surface. Bran will float on the surface.

Chalk powder Shake sample with dil.HCl Effervescence indicates chalk.

8 Common spices like Turmeric, chilly, curry powder,etc.

Colour Extract the sample with Petroleum ether and add 13N H2SO4to the extract. Appearance of red colour (which persists even upon adding  little distilled water) indicates the presence of added colours. However, if the colour disappears upon adding distilled water the sample is not adulterated.

9 Black Pepper Papaya seeds/light berries, etc.

Pour the seeds in a beaker containing Carbon tetra-chloride. Black papaya seeds float on the top while the pure black pepper seeds settle down.

10 Spices(Ground) Powdered bran and saw dust

Sprinkle on water surface. Powdered bran and sawdust float on the surface.

11 Coriander powder Dung powder Soak in water. Dung will float and can be easily detected by its foul smell.

Common salt To 5 ml. Of sample add a few drops of silver nitrate. White precipitate indicates adulteration.

12 Chillies Brick powder grit, sand, dirt, filth, etc.

Pour the sample in a beaker containing a mixture of chloroform and carbon tetrachloride. Brick powder and grit will settle at the bottom.

13 Badi Elaichi seeds Choti Elaichi seeds

Separate out the seeds by physical examination. The seeds of Badi Elaichi have nearly plain surface without wrinkles or streaks while seeds of cardamom have pitted or wrinkled ends.

14 Turmeric Powder Starch of maize, wheat, tapioca, rice

A microscopic study reveals that only pure turmeric is yellow coloured, big in size and has an angular structure. While foreign/added starches are colourless and small in size as compared to pure turmeric starch.

15 Turmeric Lead Chromate Ash the sample. Dissolve it in 1:7 Sulphuric acid (H2SO4) and filter. Add 1 or 2 drops of 0.1% dipenylcarbazide. A pink colour indicates presence of Lead Chromate.

Metanil Yellow Add few drops of conc.Hydrochloric acid (HCl) to sample. Instant appearance of violet colour, which disappears on dilution with water, indicates pure turmeric. If colour persists Metanil yellow is present.

16 Cumin seeds(Black jeera)

Grass seeds coloured with charcoal dust

Rub the cumin seeds on palms. If palms turn black adulteration in indicated.

17 Asafoetida(Heeng) Soap stone, other earthy matter

Shake a little quantity of powdered sample with water. Soap stone or other earthy matter will settle at the bottom.

Chalk Shake sample with Carbon tetrachloride (CCl4). Asafoetida will settle down. Decant the top layer and add dil.HCl to the residue. Effervescence shows presence of  chalk.

18 Foodgrains Hidden insect infestation

Take a filter paper impregnated with Ninhydrin (1% in alcohol.) Put some grains on it and then fold the filter paper and crush the grains with hammer. Spots of bluish purple colour indicate presence of hidden insects infestation

   Criteria for selection of food             Selection of wholesome and non-adulterated food is essential for daily life to make sure that such foods do not cause any health hazard. Although it is not possible to ensure wholesome food only on visual examination when the toxic contaminants are present in ppm/ppb level. However, visual examination of the food before purchase makes sure to ensure absence of insects, visual fungus, foreign matters, etc. Therefore, due care  taken by the consumer at the time of purchase of food after thoroughly examining can be of great help. Secondly, label declaration on packed food is very important for knowing the ingredients and nutritional value . It also helps in checking the freshness of the food and the period of best before use. The consumer should avoid taking food from an unhygienic place and food being prepared under unhygienic conditions. Such types of food may cause various diseases. Consumption of cut fruits being sold in unhygienic conditions should be avoided. It is always better to buy certified food from reputed shop.

                   

A consumer is one who buys and uses various products. Children, adults, elderly people all are consumers in one way or the other. Everyday we buy different products for our use.

It includes items of daily consumption like milk, vegetables, copy, pencil, etc. Items like cloth, furniture, electrical appliances are purchased occasionally. Some items such as car, house, land, etc. are normally purchased once in a lifetime.

The shop from where we do purchasing they too purchase these items from a wholesaler or the manufacturer. Therefore, the same person can be both a consumer as well as a seller. A consumer utilizes his resources-money, time, energy wisdom, etc. to buy these items.

The following problmes are faced by Consumers:Variation in Prices:

The consumer has to pay different prices for the same item at different places. Big shops are often expensive as they spend some money on the maintenance of shop, advertisements, and free home delivery which is hidden at the expense of the consumer.

Some shopkeepers charge higher price than the printed ones by putting their own price tags or increase the price by adding local taxes.

The consumer does not know whether he is paying the right price or not. To avoid this, the consumer should verify price from various shops or from super bazaar because by this, the consumer cannot be deceived.

Non-availability of items in the market:

Sometimes daily consumed items like butter, potatoes, onions, rice, etc. are not available in the market or one may get these by paying higher prices. Normally such scarcities are artificial. The moment when there is possibility of price rise of a commodity, it vanishes from the market.

It reappears in the market immediately after the price is increased. In such situation either the consumer has to do without these items or pay a higher price. In some situations like drought or floods, etc., the shopkeepers hoard stock of essential items and sell these items only when consumer agrees to pay a higher price. In such a situation the consumer should take a collective decision not to buy commodities sold in this black market.

Who is a consumer, Problems faced by consumers, Consumer education, Rights and duties of consumer, Consumer information, Consumer Aids?

Adulteration:

Adulteration of goods is one such problem which is faced by the consumer in day-to-day purchases. In the present times the biggest problem is that the consumer does

not get pure commodities like ghee, milk, spices, maida, basan, cereals, etc. even if he is prepared to pay higher prices.

Such items are sold in the market with a guarantee of purity but are found to be adulterated when used. Adulteration of yellow powder in turmeric powder, small pebbles in rice, starch in milk, and cheese and used tea leaves are generally sold in the market.

Traders do not hesitate to use such adulterants as these adulterants are injurious to health and fatal. Every day, we read about food poisoning in the newspaper. Consumer does not have any knowledge to judge the purity of edibles.

Therefore, he is compelled to buy adulterated items in ignorance. Apart from food products, the problem of adulteration is there for other consumable goods also. For example, if the terry cot cloth is not of standard mill, the seller may cheat the consumer by informing him the wrong proportion of cotton and Ethylene.

So in order to avoid such cheating, the consumer should always buy only from reli-able shops. The Government of India has enacted an act called PFA (Prevention of Food Adulteration Act) in 1954 to check such immoral acts of adulteration. This act was implemented in 1955.

Under this act, minimum standards have been fixed for all food products available in the market. It is mandatory to adopt these standards. If a food product does not conform to these standards, it will be treated as adulterated.

Unfair means of measurement.

Incorrect measurement is another problem in addition to adulteration. Often standard weights and measurements are not used in the market. For example:

Spurious, under weights, or stones, bricks, etc. are used in place of standard weights.

Sometimes the seller weighs pickings along with the goods.

The seller tries to deceive the consumer by using the hand weighing scales in place of standard scales; the hand weighing scales are usually weighs less than the actual weight

Boxes or bottles that are used in packed goods are generally of have a shape that would give lesser quantity to the consumer. For example, a bottle with heavy base and sleek bottle gives an' press ion that the quantity of goods is but in reality it is less. For maser milk, measures with raised bottom used

Magnet: Use of magnet to increase weight, Hollow weight

To prevent unfair means of measurements, government has passed certain acts from time to time-

In 1956, government has passed a stan-1 dared measurement Act.

In 1962, decimal and metric system of measurement was introduced. This system! has following units of measurement:

1. Unit of length - Meter

2. Unit of weight - Gram3. Unit for measuring liquids - Liter

In 1976, Standard Weight and Measurement Act were passed. Under this Act, use of any other method except decimal and metric system is illegal. For weighing and measuring, the use of standard weights and measures is compulsory.

In 1977, certain rules were fixed for packed products. Under these rules, weighing of the products along with the weight of the packing is illegal.

The consumer should take the following steps in order to avoid such malpractices:

(a) The fruit and vegetable vendors should not be allowed to weigh by stone or brick in place of standard weights.

(b) The bar of the hand weighing scale should be checked beforehand. In case of weighing scale, ensure that the needle is at zero.

(c) Check the weights and ensure that the weights are not hollow or with false bottom.

(d) The shopkeeper should not be allowed to weigh the goods along with packing or boxes.

(e) Before purchasing packed goods, check the weight on the label.

(f) If the consumer feels that the shopkeeper uses malpractices in weights and measures, he should immediately lodge a complaint in Weights and Measure Bureau.

Misleading advertisements

These days, a product is produced by a number of manufacturers. Everyday new products are launched. The manufacturer resorts to advertisements for the sale of their products. The advertisement gives details of quality of product and method of use to the consumer. Normally the manufacturer gives an exaggerated account of his products.

Such advertisements lure the consumer in buying these products. After the purchase, the consumer realizes that it does not match with what has been claimed in the advertisement. Such misleading advertisements cheat the consumer.

The consumer should not purchase a product only on the basis of the advertisement.

Misleading and incomplete labels

The labels on products provide information about the products to the consumer. The consumer can decide judiciously after comparing the quality and price of the product from the label. Often the manufacturers try to cheat the consumer by appending incomplete information on the label.

Sale of substandard goods

Sometimes, seller sells sub-standard goods at higher price in place of standard goods. For example, selling furniture made up of inferior quality wood after polishing, using substandard sheets in steel almirahs and furniture, selling substandard cloth by claiming it of a superior quality and inflates its price, etc. The consumer never comes to know whether the product is of a good quality or not? He knows it only after use.

In order to avoid such cheating the consumer should purchase goods from reliable shops.

Sale of inferior goods

The seller does not hesitate to sell even inferior goods. In order to earn more profit inferior medicines, cosmetics, oil, ghee, etc. are sold in original pickings.

To check the sale of such goods, the consumer should not encourage production of such goods. For this:

(a) The consumer should be vigilant while purchasing goods.

(b) The consumer should check the label carefully. In case he finds it different, he should not purchase that good.

(c) The consumer should not sell empty pickings of original goods. Rather crush these pickings to avoid reuse.

Malpractices adopted by the manufacturers or sellers.

Manufacturers or sellers lure the consumer to buy their product by adopting malpractices misleading schemes like 'free gifts' or 'heavy discounts' attracts the consumer easily. In reality, the price is inflated in the first place and then discount of 20% to 50% is offered.

There is no change in prices in reality. Sometimes the producer imitates the colour, shape, and name of popular brand available in the market. Thus the consumer is cheated and he purchases an inferior good in place of standard one.

The manufacturer of 'B' pickle has tried to cheat by using the bottle of same colour, size, and brand name as used by manufacturer of 'A' pickle.

In order to avoid such cheating, the consumer should carefully check the name and brand of the product.

10. Shortage of standardized products. Most of the goods available in the market do not carry standardized markings. When a consumer goes to the market to buy an electric iron, he finds a number of brands without standardized markings. Still these brands are very cheap. In such a situation, the consumer is not able to decide

whether he should buy a cheaper and popular bran or less popular standardized expensive brand.

The consumer should only buy standardized items because these are durable and| safe to use.