Why curd and sour substances should not be kept in brass and copper vessels?

Chemical reaction:
- Curd and sour substances contain acids which can react with brass and copper.
- This reaction can lead to the formation of toxic compounds which can be harmful if consumed.

Corrosion:
- The acidic nature of curd and sour substances can cause corrosion of brass and copper vessels.
- This can lead to the release of harmful substances into the food stored in these vessels.

Health risks:
- Consuming food stored in brass and copper vessels that have reacted with curd or sour substances can lead to health risks.
- These risks include stomach problems, nausea, and other digestive issues.

Loss of nutrients:
- The reaction between curd and brass/copper vessels can also result in the loss of essential nutrients present in the food.
- This can reduce the nutritional value of the food being stored or cooked in these vessels.

Recommendation:
- It is advisable to store curd and sour substances in glass, ceramic, or stainless steel containers to avoid any chemical reactions.
- This will help in preserving the nutritional value of the food and prevent any health risks associated with storing such substances in brass and copper vessels.