We often associate healthy eating with a diet rich in green vegetables. However, in today’s age of food adulteration, anything that looks excessively green can sometimes signal a serious problem. With the rising number of food adulteration incidents, consumers need to stay cautious while buying and consuming green vegetables and other food items, as vendors may adulterate them with Malachite Green.

Malachite Green is an organic compound commonly used in aquaculture as an antibacterial agent and in industries for dyeing purposes. In 1877, Hermann Fischer created this compound by condensing benzaldehyde and dimethylaniline in a molecular ratio of 1:2 in the presence of sulfuric acid.

Image by W. Oelen

Uses of Malachite Green

Industries in India widely use Malachite Green as an antiseptic and for dyeing cotton, wool, jute, and leather. Some manufacturers also covertly use the chemical to colour confectionery products. Laboratories use it as a green dye and a counter-stain in histology, while the aquaculture and fish farming sectors use it for its anti-fungal properties. Manufacturers also conventionally apply it as a dye for materials such as silk, paper, and leather.

Commercial aquaculture operators commonly use Malachite Green as an antibacterial agent to treat the fungus Saprolegnia, which infects fish eggs, and Ichthyophthirius multifiliis in freshwater aquaria. Fish treated with Malachite Green often contain its primary metabolite, Leucomalachite Green (LMG), which has sparked controversy and prompted government regulation.

Malachite Green harms human health and acts as a carcinogen, meaning it can cause cancer in humans. Researchers at the University used Malachite Green in tests that caused the malignant transformation of Syrian hamster embryo cells. The chemical also poses serious risks to workers in the printing and textile industries. Studies have linked Malachite Green to carcinogenesis, mutagenesis, chromosomal fractures, teratogenicity, and respiratory toxicity.

Authorities in the United States and the European Union have banned Malachite Green in food-related applications. Regulators introduced these bans after the FDA detected the chemical in imported seafood. Despite these restrictions, some countries with less stringent laws still allow its use for non-aquaculture purposes because manufacturers can produce it at a low cost.

In India, the FSSAI has banned the use of Malachite Green at any stage of processing of meat and meat products, poultry and eggs, seafood, including shrimps, prawns, or any variety of fish and fishery products.

How to Check for Malachite Green Adulteration?

Some vendors apply synthetic colours like Malachite Green and wax coatings to make fruits and vegetables appear shinier and greener. They frequently use the chemical to give chillies, cucumbers, peas, ladyfinger, and spinach a vivid green colour. The FSSAI recently released an instructional test video that helps consumers identify Malachite Green adulteration in green vegetables using liquid paraffin.

If a cotton piece soaked in liquid paraffin turns green after you dab it on the outer surface of a suspected vegetable, it indicates Malachite Green adulteration. Similarly, if the water in a glass containing green peas turns green after keeping it aside for half an hour, it indicates adulteration.

Green and Clean

Deception exists everywhere, and food adulteration continues to threaten consumers. Time and again, dishonest practices in the food industry mislead innocent people, forcing them to stay cautious even while choosing the most unsuspecting foods. In the words of Christine Pelosi, “Being green and clean is not just an aspiration but an action”.