The adulteration of turmeric with metanil yellow is illegal and poses a health hazard. Metanil yellow is a non-edible dye and is harmful to health when consumed. This type of adulteration is strictly prohibited under food safety laws.
- Option (1) "Beneficial for nutrition" is incorrect because metanil yellow is not beneficial for nutrition; it is a harmful substance.
- Option (2) "Permitted under food law" is incorrect as the use of metanil yellow in food products is illegal and not permitted.
- Option (4) "Used to enhance natural flavor" is incorrect because metanil yellow is a dye, not a flavor enhancer.
Therefore, the correct answer is "Illegal and a health hazard."