Types of food adulteration

Introduction

Adulteration is as the process by which the quality or the nature of a given substance is reduced through (i) the addition of a foreign or an inferior substance and (ii) the removal of a vital element.

Types

• Intentional adulterants

Sand, marble chips, stones, mud, other filth, talc, chalk powder, water, mineral oil

• Incidental adulterants

Pesticide residues tin from can, droppings of rodents, larvae in foods.

• Metallic contamination

Arsenic from pesticides, lead from water, mercury from effluent, from chemical industries, tins from cans.

Intentional Adulteration-Methods of Detection

• Name of the Food Article

Ghee or Butter

Adulterant

Vanaspathi

Detection of Adulterant

Take about one teaspoonful of melted ghee or butter with equal quantity concentrated. Hydrochloric Acid in a test tube and add to it a pinch of cane sugar. Shake well for one minute and test it after 5 minutes. Appearance of crimson colour in lower (acidic) layer shows the presence of ‘vanaspathi’.

Detection of Adulterant –(Mashed potatoes, sweet potato and other starches)

The presence of mashed potatoes and sweet potatoes in a sample of butter can easily be detected by adding a drop of tincture of iodine. Iodine, which is brownish in colour, turns to blue if mashed potatoes/sweet potatoes/other starches are present.

• Name of the Food Article

Milk

Adulterant

Water

Detection of Adulterant

• Name of the Food Article

Sweet meat, ice cream, sherbhat

Adulterant

Metanil yellow (a non permitted coal tar dye)

Detection of Adulterant

Extract colour with Luke warm water from food article. Add few drops of conc. Hydrochloric Acid. If magenta red colour develops the presence of metanil yellow is indicated.

• Name of the Food Article

Dhals

Adulterant

Kesari dhal

Detection of Adulterant

Add 50 ml of dilute Hydrochloric acid to dal and keep on simmering water for about 15 minutes. The pink colour if developed indicates the presence of kesari dal.

Adulterant

Clay, stones, gravels, lead chromate (yellow)

Detection of Adulterant

Visual examination will detect these adulterants. Shake five grams of dal with 5 ml of water and add a few drops of Hydrochloric Acid. A pink colour shows the presence of colour.

• Name of the Food Article

Tea leaves

Adulterant

Exhausted tea or black or Bengal gram dal husk with colour.

Detection of Adulterant

• Name of the Food Article

Wheat, bajra and other food grains

Adulterant

Ergot (a fungus containing a poisonous substance)

Detection of Adulterant

• Name of the Food Article

Sugar

Adulterant

Chalk powder

Detection of Adulterant

Dissolve in a glass of water, chalk will settle down at the bottom.

• Name of the Food Article

Turmeric

Adulterant

Coloured saw dust metanil yellow.

Detection of Adulterant

Take a teaspoon full of turmeric powder in a test tube. Add a few drops of conc. Hydrochloric Acid. Instant appearance of violet colour which disappears on dilution with water. If the colour persists metanil yellow (an artificial dye) non-permitted coal tar dye is indicated.

• Name of the Food Article

Chilli powder

Adulterant

Stones

Detection of Adulterant

Any grittiness that may be felt on tapping the sediment at the bottom of glass confirms the presence of brick powder or sand. Smooth white residue at the bottom indicates the presence of soapstone.

Adulterant

Artificial colour

Detection of Adulterant

Water soluble artificial dye can be detected by sprinkling a small quantity of chilli or turmeric powder on the surface of water contained in a glass tumbler. The soluble dye will immediately start descending in colour streaks.

• Name of the Food Article

Jaggery powder

Adulterant

Chalk powder

Detection of Adulterant

Add few drops of HCl. Effervescence indicate adulteration. Stir a spoonful sample of sugar in a glass of water. The chalks settle down.

• Name of the Food Article

Wheat flour (maida)

Adulterant

Atta from which maida suji has been extracted

Detection of Adulterant

When dough is prepared from resultant wheat flour, more water has to be used and chapaties prepared out of this will blow out. The normal taste of chapaties prepared out of wheat is some what sweetish whereas those prepared out of adulterated wheat flour will taste insipid.

• Name of the Food Article

Common salt

Adulterant

White powdered stone, chalk

Detection of Adulterant

Stir a spoonful of simple of salt in a glass of water. The presence of chalk will make the solution white and other insoluble impurities will settle down.

• Name of the Food Article

Mustard seeds

Adulterant

Argemone seeds

Detection of Adulterant

Mustard seeds have a smooth surface. The argemone seed have grainy and rough surface and are blacker hence can be separated out by close examination.

• Name of the Food Article

Honey

Adulterant

Molasses (sugar and water)

Detection of Adulterant

A cotton wick dipped in pure honey when lighted with a match stick burns. If adulterate the presence of water will not allow the honey to burn. If it does it will produce a crackling sound.

• Name of the Food Article

Cinnamon

Adulterant

Cassia bark

Detection of Adulterant

Cinnamon barks are very thin. Cassia barks are thick and stiff. Cinnamon barks can be rolled.

• Name of the Food Article

Coffee

Adulterant

Chicory

Detection of Adulterant

Gently sprinkle the coffee powder sample on the surface of water in a glass. The coffee floats over the water but chicory begins to sink down within a few seconds. The falling chicory powder particles leave behind them a trail of colour due to large amount of caramel they contain.

Incidental Poisoning

Food Borne Diseases Caused by Some Pathogenic Organisms

Pathogenic Organisms	Food Commonly involved	III effects and diseases
BACTERIAL
Bacillus cereus	Cereal Products	Nausea, vomiting, abdominal pain.
Clostridium botulinum toxins	Defectively processed meat and fish.	Botulism (muscular) paralysis, death due to respiratory failure.
Clostridium perfringens (welchii)	Defectively processed meat and fish.	Nausea, abdominal pain and diarrhoea.
Salmonella	Defectively processed meat, fish and egg products, raw vegetables grown on sewage.	Salmonellosis (vomiting diarrhoea and fever)
Shigella sonnei	Foods kept exposed or sale in unhygienic surroundings.	Bacillary dysentery
Staphylococcus aureus	Foods kept exposed or sale in unhygienic surroundings.	Increased salivation, vomiting, abdominal pain and diarrhoea.
Streptococcus pyogenes	Foods kept exposed or sale in unhygienic surroundings.	Scarlet fever, septic sores throat.
FUNGAL
Aspergillus flavus (aflatoxin)	Corn and groundnut	Liver damage and cancer
Claviceps purpurea (Ergot)	Rye and pearl millet infested with ergot. Peripheral gangrene	Ergotism (burning sensation in extremities)
Fusarium sporotrichiodies	Cereals and millets infected with fusarium.	Alimentary toxic aleukia.
Penicillium islandicum	Rice	Liver damage
PARASITIC
Trichinella spiralis	Pork and pork products	Nausea,vomiting,diarrhoea, Colic and muscular pains(trichionosis)
Ascaris lumbricoides	Raw vegetables grown on sewage farm.	Ascariasis
Entamoeba histolytica	Raw vegetables grown on sewage farm.	Amoebic dysentery
Ancylostoma duodenale (hookworm)	Raw vegetables grown on sewage farm.	Epigastric pain, loss of blood, anaemia.

Toxic Effects of Some Metals and Chemicals

Name	Foods commonlyinvolved	Toxic effects
Arsenic	Fruits sprayed by lead arsenate.	Dizziness, chills, cramps paralysis leading to death.
Barium	Foods contaminated by rat poison (barium carbonate)	Violent peristalsis, muscular twitching and convulsions.
Cadmium	Fruit juices and soft drinks that come in contact with cadmium and plated vessels.	Excessive sallvation, liver, kidney damage, prostate cancer, multiple fractures (painful ‘Itai-Itai’ disease reported from Japan due to cadmium poisoning)
Cobalt	Water, beer	Cardiac failure
Copper	Acid foods in contact with tranished copper ware.	Vomiting, diarrnoea, abdominal pain.
Lead	Some processed foods Lead water pipes.	Paralysis, brain damage.
Mercury	Mercury fungicide treated seed grains or mercury contaminated fish.	Paralysis, brain damage and blindness.
Tin	Canned foods	Colic, vomiting, photophobia.
Zinc	Foods stored in galvanised iron ware.	Dizziness, vomiting
pesticides	All types of foods	Acute or chronic poisoning causing damage to liver, kidney, brain and nerves leading to death.
Diethyl stilbestrol	Present in meat of stilbestrol fed animals and birds.	Teratogenesis, carcinogenesis.
antibiotics	Meat from animals fed antibiotics.	Drug resistance, hardening of arteries, heart disease.

Packaging Hazards

Polyethylene, polyvinyl chloride and allied compounds are used to produce flexible packaging material. While this method of packaging is very convenient, it must not contain any noxious thermal breakdown products, which could be injurious to health. Further, temperatures used for heat sealing, or sterilization should not result in formation of toxic residues. To avoid such incidences, it is essential that only food grade plastic packaging materials be used for packaging foods.

Toxicants Naturally Present In Some Foods

Some foods contain toxic substances, which may cause serious illness, when consumed in large amounts. An important example is the legume, Lathyrus sativus which contain a toxin which may produce neurotoxic effects. The alcoholic extract of lathyrus sativus seeds contain a toxin B-N-oxalyt amino-L-alanine (BOAA).

When consumed in large amounts, it subjects develop a crippling disease known as lathyrism. The toxin can be easily removed by soaking the pulse in hot water and discarding the water.

Some varieties of mushrooms contain toxic substances which when consumed produce serious ill-effects. For example, ananita phalloides contains the toxin called phalloidin which causes hypoglycaemia and convulsions, vomiting in human subjects. Liver and kidney damages also occur.

Introduction

Adulteration is as the process by which the quality or the nature of a given substance is reduced through (i) the addition of a foreign or an inferior substance and (ii) the removal of a vital element.

Types

• Intentional adulterants

Sand, marble chips, stones, mud, other filth, talc, chalk powder, water, mineral oil

• Incidental adulterants

Pesticide residues tin from can, droppings of rodents, larvae in foods.

• Metallic contamination

Arsenic from pesticides, lead from water, mercury from effluent, from chemical industries, tins from cans.

Intentional Adulteration-Methods of Detection

• Name of the Food Article

Ghee or Butter

Adulterant

Vanaspathi

Detection of Adulterant

Take about one teaspoonful of melted ghee or butter with equal quantity concentrated. Hydrochloric Acid in a test tube and add to it a pinch of cane sugar. Shake well for one minute and test it after 5 minutes. Appearance of crimson colour in lower (acidic) layer shows the presence of ‘vanaspathi’.

Detection of Adulterant –(Mashed potatoes, sweet potato and other starches)

The presence of mashed potatoes and sweet potatoes in a sample of butter can easily be detected by adding a drop of tincture of iodine. Iodine, which is brownish in colour, turns to blue if mashed potatoes/sweet potatoes/other starches are present.

• Name of the Food Article

Milk

Adulterant

Water

Detection of Adulterant

• Name of the Food Article

Sweet meat, ice cream, sherbhat

Adulterant

Metanil yellow (a non permitted coal tar dye)

Detection of Adulterant

Extract colour with Luke warm water from food article. Add few drops of conc. Hydrochloric Acid. If magenta red colour develops the presence of metanil yellow is indicated.

• Name of the Food Article

Dhals

Adulterant

Kesari dhal

Detection of Adulterant

Add 50 ml of dilute Hydrochloric acid to dal and keep on simmering water for about 15 minutes. The pink colour if developed indicates the presence of kesari dal.

Adulterant

Clay, stones, gravels, lead chromate (yellow)

Detection of Adulterant

Visual examination will detect these adulterants. Shake five grams of dal with 5 ml of water and add a few drops of Hydrochloric Acid. A pink colour shows the presence of colour.

• Name of the Food Article

Tea leaves

Adulterant

Exhausted tea or black or Bengal gram dal husk with colour.

Detection of Adulterant

• Name of the Food Article

Wheat, bajra and other food grains

Adulterant

Ergot (a fungus containing a poisonous substance)

Detection of Adulterant

• Name of the Food Article

Sugar

Adulterant

Chalk powder

Detection of Adulterant

Dissolve in a glass of water, chalk will settle down at the bottom.

• Name of the Food Article

Turmeric

Adulterant

Coloured saw dust metanil yellow.

Detection of Adulterant

Take a teaspoon full of turmeric powder in a test tube. Add a few drops of conc. Hydrochloric Acid. Instant appearance of violet colour which disappears on dilution with water. If the colour persists metanil yellow (an artificial dye) non-permitted coal tar dye is indicated.

• Name of the Food Article

Chilli powder

Adulterant

Stones

Detection of Adulterant

Any grittiness that may be felt on tapping the sediment at the bottom of glass confirms the presence of brick powder or sand. Smooth white residue at the bottom indicates the presence of soapstone.

Adulterant

Artificial colour

Detection of Adulterant

Water soluble artificial dye can be detected by sprinkling a small quantity of chilli or turmeric powder on the surface of water contained in a glass tumbler. The soluble dye will immediately start descending in colour streaks.

• Name of the Food Article

Jaggery powder

Adulterant

Chalk powder

Detection of Adulterant

Add few drops of HCl. Effervescence indicate adulteration. Stir a spoonful sample of sugar in a glass of water. The chalks settle down.

• Name of the Food Article

Wheat flour (maida)

Adulterant

Atta from which maida suji has been extracted

Detection of Adulterant

When dough is prepared from resultant wheat flour, more water has to be used and chapaties prepared out of this will blow out. The normal taste of chapaties prepared out of wheat is some what sweetish whereas those prepared out of adulterated wheat flour will taste insipid.

• Name of the Food Article

Common salt

Adulterant

White powdered stone, chalk

Detection of Adulterant

Stir a spoonful of simple of salt in a glass of water. The presence of chalk will make the solution white and other insoluble impurities will settle down.

• Name of the Food Article

Mustard seeds

Adulterant

Argemone seeds

Detection of Adulterant

Mustard seeds have a smooth surface. The argemone seed have grainy and rough surface and are blacker hence can be separated out by close examination.

• Name of the Food Article

Honey

Adulterant

Molasses (sugar and water)

Detection of Adulterant

A cotton wick dipped in pure honey when lighted with a match stick burns. If adulterate the presence of water will not allow the honey to burn. If it does it will produce a crackling sound.

• Name of the Food Article

Cinnamon

Adulterant

Cassia bark

Detection of Adulterant

Cinnamon barks are very thin. Cassia barks are thick and stiff. Cinnamon barks can be rolled.

• Name of the Food Article

Coffee

Adulterant

Chicory

Detection of Adulterant

Gently sprinkle the coffee powder sample on the surface of water in a glass. The coffee floats over the water but chicory begins to sink down within a few seconds. The falling chicory powder particles leave behind them a trail of colour due to large amount of caramel they contain.

Incidental Poisoning

Food Borne Diseases Caused by Some Pathogenic Organisms

Pathogenic Organisms	Food Commonly involved	III effects and diseases
BACTERIAL
Bacillus cereus	Cereal Products	Nausea, vomiting, abdominal pain.
Clostridium botulinum toxins	Defectively processed meat and fish.	Botulism (muscular) paralysis, death due to respiratory failure.
Clostridium perfringens (welchii)	Defectively processed meat and fish.	Nausea, abdominal pain and diarrhoea.
Salmonella	Defectively processed meat, fish and egg products, raw vegetables grown on sewage.	Salmonellosis (vomiting diarrhoea and fever)
Shigella sonnei	Foods kept exposed or sale in unhygienic surroundings.	Bacillary dysentery
Staphylococcus aureus	Foods kept exposed or sale in unhygienic surroundings.	Increased salivation, vomiting, abdominal pain and diarrhoea.
Streptococcus pyogenes	Foods kept exposed or sale in unhygienic surroundings.	Scarlet fever, septic sores throat.
FUNGAL
Aspergillus flavus (aflatoxin)	Corn and groundnut	Liver damage and cancer
Claviceps purpurea (Ergot)	Rye and pearl millet infested with ergot. Peripheral gangrene	Ergotism (burning sensation in extremities)
Fusarium sporotrichiodies	Cereals and millets infected with fusarium.	Alimentary toxic aleukia.
Penicillium islandicum	Rice	Liver damage
PARASITIC
Trichinella spiralis	Pork and pork products	Nausea,vomiting,diarrhoea, Colic and muscular pains(trichionosis)
Ascaris lumbricoides	Raw vegetables grown on sewage farm.	Ascariasis
Entamoeba histolytica	Raw vegetables grown on sewage farm.	Amoebic dysentery
Ancylostoma duodenale (hookworm)	Raw vegetables grown on sewage farm.	Epigastric pain, loss of blood, anaemia.

Toxic Effects of Some Metals and Chemicals

Name	Foods commonlyinvolved	Toxic effects
Arsenic	Fruits sprayed by lead arsenate.	Dizziness, chills, cramps paralysis leading to death.
Barium	Foods contaminated by rat poison (barium carbonate)	Violent peristalsis, muscular twitching and convulsions.
Cadmium	Fruit juices and soft drinks that come in contact with cadmium and plated vessels.	Excessive sallvation, liver, kidney damage, prostate cancer, multiple fractures (painful ‘Itai-Itai’ disease reported from Japan due to cadmium poisoning)
Cobalt	Water, beer	Cardiac failure
Copper	Acid foods in contact with tranished copper ware.	Vomiting, diarrnoea, abdominal pain.
Lead	Some processed foods Lead water pipes.	Paralysis, brain damage.
Mercury	Mercury fungicide treated seed grains or mercury contaminated fish.	Paralysis, brain damage and blindness.
Tin	Canned foods	Colic, vomiting, photophobia.
Zinc	Foods stored in galvanised iron ware.	Dizziness, vomiting
pesticides	All types of foods	Acute or chronic poisoning causing damage to liver, kidney, brain and nerves leading to death.
Diethyl stilbestrol	Present in meat of stilbestrol fed animals and birds.	Teratogenesis, carcinogenesis.
antibiotics	Meat from animals fed antibiotics.	Drug resistance, hardening of arteries, heart disease.

Packaging Hazards

Polyethylene, polyvinyl chloride and allied compounds are used to produce flexible packaging material. While this method of packaging is very convenient, it must not contain any noxious thermal breakdown products, which could be injurious to health. Further, temperatures used for heat sealing, or sterilization should not result in formation of toxic residues. To avoid such incidences, it is essential that only food grade plastic packaging materials be used for packaging foods.

Toxicants Naturally Present In Some Foods

Some foods contain toxic substances, which may cause serious illness, when consumed in large amounts. An important example is the legume, Lathyrus sativus which contain a toxin which may produce neurotoxic effects. The alcoholic extract of lathyrus sativus seeds contain a toxin B-N-oxalyt amino-L-alanine (BOAA).

When consumed in large amounts, it subjects develop a crippling disease known as lathyrism. The toxin can be easily removed by soaking the pulse in hot water and discarding the water.

Some varieties of mushrooms contain toxic substances which when consumed produce serious ill-effects. For example, ananita phalloides contains the toxin called phalloidin which causes hypoglycaemia and convulsions, vomiting in human subjects. Liver and kidney damages also occur.

Regular ‘market basket’ surveys to warn people of dangerous build up of toxins in food.

Stepping up the integrated pest management programme to teach farmers to use pesticides judiciously. No spraying should be done a week before harvest.

Taking up on a warfooting the control of pest using their natural predators.

Preventing industries from dumping poisonous effluents.

Considering health costs while deciding pesticide policy.

Use safer pesticides like synthetic pyrethroids or Malathion.

A thorough washing of vegetables does help to get rid of much of toxin.

Purple black longer size grains in bajra show the presence of ergots.

Put some grains in a glass containing 20% salt solution. Ergot floats over the surface while sound grains settle down.

Tea leaves sprinkled on wet filter paper would immediately release added colour.

Spread a little slaked lime on white porcelain tile or glass plate. Sprinkle a little tea dust on the lime. Red orange or other shades of colour spreading on the lime will show the presence of coal tar dye. In the case of genuine tea, there will be only a slight greenish yellow colour due to chlorophyll, which appears after sometime.

The Lactometer reading should not ordinarily be less than 1.026.

The presence of water can be detected by putting a drop of milk on a polished vertical surface. The drops of pure milk either stops or flows slowly leaving a white trail behind it. Whereas milk adulterated with water will flow immediately without leaving a mark.

Regular ‘market basket’ surveys to warn people of dangerous build up of toxins in food.

Stepping up the integrated pest management programme to teach farmers to use pesticides judiciously. No spraying should be done a week before harvest.

Taking up on a warfooting the control of pest using their natural predators.

Preventing industries from dumping poisonous effluents.

Considering health costs while deciding pesticide policy.

Use safer pesticides like synthetic pyrethroids or Malathion.

A thorough washing of vegetables does help to get rid of much of toxin.

Purple black longer size grains in bajra show the presence of ergots.

Put some grains in a glass containing 20% salt solution. Ergot floats over the surface while sound grains settle down.

Tea leaves sprinkled on wet filter paper would immediately release added colour.

Spread a little slaked lime on white porcelain tile or glass plate. Sprinkle a little tea dust on the lime. Red orange or other shades of colour spreading on the lime will show the presence of coal tar dye. In the case of genuine tea, there will be only a slight greenish yellow colour due to chlorophyll, which appears after sometime.

The Lactometer reading should not ordinarily be less than 1.026.

The presence of water can be detected by putting a drop of milk on a polished vertical surface. The drops of pure milk either stops or flows slowly leaving a white trail behind it. Whereas milk adulterated with water will flow immediately without leaving a mark.

How to detect adulteration in Honey with 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.
 

Food adulteration detection methods

Adulterants, both harmful and simple, can be detected easily through small tests. These tests can be done at home too. What one needs is a set of equipment and chemicals and the culprits can be found out easily through these simple anti-adulteration tests.
Here are a few such tests as suggested by the Union Ministry of Health and Family Welfare, Government of India:

Vegetable oils:

Vegetable oils are generally mixed with castrol oil or argemone oil to make quick profits. These adulterants can be detected by the following two tests: In case of castrol oil: Take 1 ml. of vegetable 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.
In case of argemone oil: Add 5 ml concentrated HNO3 ¬¬to 5 ml.sample. Shake carefully. Allow to separate. Yellow, orange yellow or crimson colour in the lower acid layer indicates adulteration.

Ghee:

Ghee is generally mixed with mashed potato or sweet potato to make it weighty and creamy. Often vanaspati is also added to Ghee.
In case of mashed potato or sweet potato: Boil 5 ml. o the sample in a test tube. Cool and put a drop of iodine solution. Blue colour indicates presence of starch. Colour disappears on boiling and reappears on cooling.
In case of vanaspati: Take 5 ml. of the sample in a test tube. Add 5 ml. of hydrochloric acid and 0.4 ml of 2 per cent furfural solution or sugar crystals. Insertthe glass stopper and shake for 2 minutes. Development of a pink or red colour indicates presence of vanaspati in Ghee.
Often old ghee (rancid stuff) is added. To detect this, 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 per cent of ether solution of phloroglucinol. Restopper and shake for 30 seconds and allow to stand for 10 minutes. A pink or red colour in the lower acid layer indicates rancidity.

Synthetic colours in food items:

To find out whether synthetic colouring matter is used in food items, 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 per cent 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.

Honey:

Honey is good for health and it has several curative properties. But honey is generally adulterated with invert sugar or jaggery. There are two tests to find out whether the honey in question is pure or adulterated.
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 concentrated HCL.). Appearance of cherry red colour indicates presence of sugar/jaggery.
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.

Pulses and Besan:

Besan atta or pulses are adulterated with Kesari dal (Lathyrus sativus). To find out the adulterant, add 50 ml. of diluted HCL to a small quantity of dal and keep on simmering water for about 15 minutes. The pink colour, if developed, indicates the presence of Kesari dal.
Pulses are also adulterated with metanil yellow dye. To find this out, add concentrated 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.
To find out whether lead chromate is used in the pulses, shake 5 gm. of pulses with 5ml. of water and add a few drops of HCL. Pink colour indicates lead chromate.

Wheat flour or atta:

Atta is generally contaminated with excessive sand and dirt. Shake a little quantity of sample with about 10 ml of carbon tetrachloride and allow to stand. Grit and sandy matter will collect at the bottom.
Often chalk powder is used in atta. To find out, shake sample with diluted HCL. Effervescence indicates chalk

Common spices:

Common spices like turmeric, chilly and curry powder are also adulterated by colours.
Extract the sample with petroleum ether and add 13N H2SO4 to 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.
Spices (ground) are adulterated by red bran and saw dust. Sprinkle on water surface. Powdered bran and sawdust float on the surface.
Coriander powder is adulterated with dung powder. To find out, soak in water. Dung will float and can be easily detected by its foul smell.

Chillies:

Brick powder, grit, sand, dirt, filth, etc are used in chillies, especially chilli powder. Pour the sample in a beaker containing a mixture of chloroform and carbon tetrachloride. Brick powder and grit will settle at the bottom.

Turmeric:

Lead chromate is used to give turmeric its natural color. Ash the sample. Dissolve it in 1:7 sulphuric acid (H2SO4) and filter. Add 1 or 2 drops of 0.1 per cent dipenylcarbazide. A pink colour indicates presence of lead chromate.

Cumin seeds:

Grass seeds coloured with charcoal dust is used. Rub the cumin seeds on palms. If palms turn black adulteration in indicated.

Asafoetida (Heeng):

Items like soap stone and other earthy matter is used for adulteration. Shake a little quantity of powdered sample with water. Soap stone or other earthy matter will settle at the bottom.
In case chalk is used as an adulterant, shake sample with carbon tetrachloride (CCl4). Asafoetida will settle down. Decant the top layer and add diluted HCL to the residue. Effervescence shows presence of chalk.

Foodgrains:

Foodgrains contain hidden insect infestations. To test the adulterants, take a filter paper impregnated with ninhydrin (1 per cent 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 insect infestation.

Nano technology helps to check food quality

Developing Nanotechnology To Test Food Quality

ScienceDaily (July 26, 2007) — Researchers have created two tiny instruments capable of detecting a range of contaminants, from molecules to whole bacteria, in food and water, according to an article in the August issue of Microbiology Today.

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Cantilevers are miniature diving boards that measure 200 micrometers long and 40 micrometers wide, about half the width of a human hair. Two cantilevers are placed in a sensor and liquid is passed through them. When the molecule or microbe that is being looked for binds to its surface, the board bends and its electrical resistance is altered. Detection is achieved by measuring the change in resistance.

The device can be designed to search for specific things, for example, if the organism to be detected was E. coli, the cantilever could be coated in antibodies specific to E. coli cells. Many different molecules or organisms can also be recognized simultaneously. “The sensor can be expanded to contain several cantilevers, each coated with a specific detector molecule” says Professor Anja Boisen.

Lid devices also have a flexible board or ‘lid’ but it is placed on top of a tiny box that contains marker molecules, which produce colour visible to the naked eye. An organism, for example, binds to the lid, which then opens and releases the colour, indicating the presence of the organism. This can also be achieved by coating the board with ‘food’ for bacteria instead of binding molecules, so deflection occurs when the coating is removed. It can therefore be used to measure bacterial activity. The device is contained in a 1cm plastic box so, like the cantilever, it is portable.

Cantilevers and lid devices may soon be available to consumers. “We use processes where the cantilevers are fabricated by etching a thin silicon wafer three-dimensionally” says Professor Anja Boisen. “The procedure is suitable for mass production and it might be possible to make sensors so cheaply that they can be disposable.”

The applications for this new technology are abundant. The sensors can detect DNA, so may be used to test for human genetic diseases. They are also extremely sensitive and can measure deflections of just 1 nanometre, so are able to detect the presence of very small molecules. Conversely, whole bacteria and even parts of bacteria can be identified, making the sensors ideal for testing the quality of water and food samples.

“The lid device could be included in food packaging since it requires no external energy and is cheap to make. When a food is infected, the control unit in the plastic wrapping becomes coloured. Thus a simple colour indicator can show the quality of the food.

some more tips for food adulteration

Some of the tests by which adulteration in food stuffs is determined.

A food article is said to be adulterated, when it contains other substances, whose presence affects its quality or renders it harmful and does not meet prescribed standards.

1. Milk - Test for adulteration with starch:-

About 2 cm3 of milk sample is boiled and cooled. Added a few drops of iodine solution.

Blue colour indicates the presence of starch.


2. Milk - Test for adulteration with sucrose:-

About 5 cm3 sample of milk is treated with 1 cm3 of conc. hydrochloric acid and 1cm3 solution of resorcinol. The mixture is heated in a water bath for 5 minutes.

Red Colour indicates the presence of sucrose.

3. Ghee or butter - Test for adulteration with vanaspathi:-

A teaspoonful of ghee or butter sample is melted in a test tube and treated with 2cm3 of concentrated hydrochloric acid. A pinch of cane sugar is added, shaken well for 1 minute and kept aside for 5 minutes.

Crimson colour of the lower layer indicates the presence of vanaspathi.

4. Ghee or butter - Test for adulteration with mashed potato:-

About little of ghee or butter sample is melted in a test tube. Added a few drops of iodine solution.

Blue colour indicates the presence of starch.

5. Edible oil - Test for adulteration with mineral oil:-

About 2 cm3 of edible oil sample is treated with 2 cm3 of alcoholic potash in a small conical flask. Heated on a water bath for 15 mins and diluted with 10 cm3 of water.

Any turbidity shows the presence of mineral oil.

6. Sugar powder - Test for adulteration with washing soda:-

A little of sugar powder sample is shaken with little of water in a test tube. Some turbidity is observed, which on treatment with dil. Hydrochloric acid produces effervescence.

This indicates the presence of washing soda. 

Common Adulterants/Contaminants in food and Simple screening tests for their detection

Common Adulterants/Contaminants

in 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 Involved	Diseases or Health Effects
	Adulterants in food
1	Argemone seeds Argemone oil	Mustard seeds Edible 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	Paralysis
5	Rancid oil	Oils	Destroys vitamin A and E
6	Sand, marble chips, stones, filth	Food grains, pulses etc.	Damage digestive tract
7	Lathyrus sativus	Khesari dal alone or Mixed in other pulses	Lathyrism (crippling spastic paraplegia)
	Chemical Contamination
8	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, diarrhoea
17	Tin	Food	Colic, vomiting
18	Zinc	Food	Colic, vomiting
19	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 contamination
20	Bacillus cereus	Cereal products, custards, puddings, sauces	Food 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 aureus Entero-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 toxins A,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	Cancer
28	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 contamination
38	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 from Fusarium 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 from Penicillium inslandicum Penicillium atricum, Penicillium citreovirede, Fusarium, Rhizopus, Aspergillus	Yellow rice	Toxic mouldy rice disease
43	Sterigmatocystin from Aspergillus versicolour Aspergillus 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 histolytica Viral	Raw vegetables and fruits	Amoebic dysentery
46	Virus of infectious Hepatitis (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 Contamination
48	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	Cancer
51	Cyanogenetic compounds	Bitter almonds, apple seeds, cassava, some beans etc.	Gastro-intestinal disturbances
52	Polycyclic Aromatic Hydrocarbons(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