Page 1: Detection of Adulterants in Foods

General Information

• Adulteration refers to the practice of adding inferior substances to food products, potentially compromising quality, safety, and nutrition.

Common Adulterants and Detection Methods

• Green Vegetables

  • Adulterant: Malachite Green

  • Detection Method: Soak a cotton piece in liquid paraffin; rub on the outer green surface. Cotton turning green indicates adulteration.

• Saffron

  • Adulterant: Dried tendrils of maize cobs

  • Detection Method: Pure saffron will not easily break; artificial saffron dissolves in water, coloring the water.

• Common Salt

  • Adulterant: White powder (chalk)

  • Detection Method: Stir salt in water; presence of chalk makes the solution white, and insoluble impurities settle.

• Iodized Salt

  • Adulterant: Common salt

  • Detection Method: Add salt to potato and lemon juice; blue color indicates iodized salt.

• Tea Leaves

  • Adulterant: Exhausted tea

  • Detection Method: Sprinkle tea dust on slaked lime; red/orange color indicates coal tar color, while pure tea gives slight greenish yellow from chlorophyll.

• Vinegar

  • Adulterant: Mineral acid

  • Detection Method: Test with Metanil yellow paper; color change from yellow to pink indicates mineral acid.

• Milk

  • Adulterants: Water, Starch, Urea

  • Detection Methods:

    • Water: Drop milk on a slanted polished surface; pure milk leaves a trail, while adulterated milk flows immediately.

    • Starch: Add iodine solution; blue color indicates starch.

    • Urea: Mix milk with soybean powder; red litmus paper changing to blue indicates urea.

Specific Testing Methods for Milk and Milk Products

• Vanaspati

  • Detection: Add hydrochloric acid and sugar; red color indicates presence of vanaspati in milk.

• Formalin

  • Detection: Layer milk with concentrated sulfuric acid; violet ring indicates formalin.

• Detergents

  • Detection: Shake milk with water; lather formation indicates detergent.

• Synthetic Milk

  • Characteristics: Bitter aftertaste, gives soapy feel, turns yellowish on heating.

• Testing for Protein: Urease strips can test for synthetic milk, which is devoid of protein.

Page 2: Milk and Milk Product Adulterants

Common Adulterants

• Food Article: Renowned tests with precise methods for common milk products continue across various testing mediums, enhancing reliability and accuracy.

• Ghee and Butter Testing:

  • Vanaspati and Margarine detection involved using hydrochloric acid and sugar; appearance of crimson color indicates either presence.

• Presence of Starch: Similar methods as above; boiling samples with iodine solution yields a blue color if starch is present.

Page 3: Oils and Fats

Common Adulterants

• Ghee

  • Adulterant: Vanaspati or Margarine

  • Detection: Hydrochloric acid added with sugar shows crimson color upon successful addition.

• Butter

  • Similar Detection: Same method as ghee.

• Edible Oils

  • Adulterants: Prohibited colors; tests include hydrochloric acid treatments indicating adulteration.

Page 4: Sweetening Agents

Common Adulterants

• Sugar: Chalk powder and urea detection through settling in water and effervescence with HCl.

• Jaggery: Tests indicated chalk presence through visually observable reactions.

Page 5: Miscellaneous Detection Techniques

Food Article Tests

• Corinder Powder: Examined visually for purity; floatation in water indicates adulteration.

• Processed Foods: Defined as any alteration from natural states including potential harmful substances identifiable through tests.

• Pulses and Grains: Specific adulterants; examples prescribed for grains include ergot, dhatura, and others, facilitating safe consumption practices.

Conclusion

• Extensive methods for detecting various food adulterants range from simple visual tests to complex chemical analyses due to the serious implications of adulteration.