Food Adulteration

We have just  discussed various aspects of food contamination. We did differentiate between food contaminants and additives in the last section. Let us now move on to a study of food adulteration.

Adulteration is  act by which

• something is added to a food item which is inferior in quality or makes it impure with the intention of making more profit or
• something is removed from a food item which reduces its quality.

The commonest examples are adding water to milk in order to increase volume, and removing part of the cream from the milk without the consumer's  knowledge. Mixing green cardamoms from which essential oils have been removed with good quality green cardamoms is also an example of adulteration. Any  substance which is used to adulterate a particular item of food is called an adulterant. Water is an adulterant for milk and semolina is an adulterant for fine grained sugar. Metanil yellow which issued to give a bright, yellow color to turmeric is an adulterant. Papaya seeds are adulterants for black pepper.

Adulterated food may only make us undergo a monetary loss by making us pay partly for the rubbish that is added to the food. However, it may actually endanger health like in the case of metanil yellow as you will see in the following discussion.

Common Adulterants and their Health Hazards:

Adulterants need not always be harmful. Unscrupulous shopkeepers mix poorer quality rice in better quality rice (such as basmati). This is a good example. The poor quality rice would not harm us. However, this does mean not getting full value for our money. There are, however, several adulterants that can cause harm. We have listed these here:

• Sand, marble chips, gravel and earth - mostly added to grains, pulses, coriander seeds, rice, etc. If ingested they can upset the digestive system besides beingcarriers of infection. They are extremely unpleasant in the mouth and can hurt the teeth and the gums.
• Water - mostly used to adulterate milk. Generally the source of the water is not clean and therefore it also carries infections.
• Petroleum oils - used for adulterating edible oils. Used motor oils are an example. These oils are toxic and cancer-causing.
• Mineral oil - used for coating black pepper to prevent fungal growth. These can be serious health hazards as some mineral oils are toxic for human beings and contain compounds capable of causing cancer.
• Argemone seeds and oil - Argemone is a yellow-flowered plant that looks like the poppy,with  bluish, silver-veined prickly leaves. Argemone seeds resemble mustard seeds and they are mixed with them during extraction of mustard oil. Both the seeds and oil are highly toxic and the consumer can lose his eye sight and develop a condition called epidemic dropsy. When such adulteration takes place we have an epidemic of these symptoms. Dropsy is a disease in which watery fluid collects in cavities or tissues of the body causing swelling. The disease starts with gastrointestinal disturbances and irregular fever with a rash on exposed parts of the body. Death can occur due to cardiac arrest (i.e., heart stops beating).
• Lathyrus sativus (Kesari dal) - Kesari is a very hardy plant and the pulse derived from it is used to mix with bengal gram which is more expensive, in order to make bengal gram flour. In villages of Madhya Pradesh and Utter Pradesh, it is also used as wages for farm labor. It can cause a form of crippling paralysis in boys and men 5 to 45 years old. The disease is called lathyrism. The disease starts with stiffness of the knee joints and legs with pain around the knee and ankle joints, as well as in the back thighs.
• Papaya seeds - are used to adulterate black pepper.
• Talc - used to polish pulses. Talc has been linked to stomach cancer.
• Washing soda or maida - used to adulterate icing sugar.
• Metanil yellow and lead chromate - used to give colour to turmeric and to jalebies. These are highly ,poisonous. Metanil yellow affects the reproductive organs and can cause sterility. It has also been associated with stomach trouble and cancer. The possible health hazards of lead chromate include anaemia (low hemoglobin levels in blood), paralysis and brain damage especially in children.
• Used tea leaves - dried, powdered and colored, are used to adulterate tea leaves. Used tea leaves can be the cause of infection and food poisoning depending on the source from which they are collected.
• Malachite green - used to color dried peas a bright green so that they look like fresh peas. This can be poisonous and can cause cancer and abnormalities in vita) organs such as the kidney, spleen and liver. The color has also been known to cause abnormalities in the foetus in experiments conducted on animals.
• Coloured saw dust - is used to adulterate red chilli powder. This can upset digestion and cause infection.

Simple Tests to Detect Adulteration:

Tests are available by which one can detect adulteration in quite a few of our commonly adulterated foods. Some of them do require a few simple reagents and chemicals or tools which can be easily purchased without too much cost, and it is worth going to the trouble of keeping a stock of these for ready testing. Let us talk about the simplest of these tests.

Detecting the presence of excess water in milk - This can be done by measuring the specific gravity of the milk with a small gadget called a lactometer. You can buy it in the market. Try the scientific equipment shops. A specific gravity reading of less than 4 is an indication of express water in milk.

Detecting fine sand or semolina in fine-grained sugar or salt - Stir a little of the sample into a glass of clean water. The sugar or salt will dissolve leaving a residue of the sand or semolina at the bottom of the glass.

Detecting sand or dirt in jaggery - Boil a little jaggery in water. Jaggery will dissolve leaving sand and dirt at the bottom.

Detecting adulteration of black pepper with papaya seeds - Put a sample in a glass of water. Papaya seeds will float and the pepper corns will settle at the bottom.

You would have noticed that these tests did not require you to use any special equipment or chemical reagents.  Appendix 5 gives you some simple tests that do require special equipment and chemicals.