Used cooking oil is easy to reuse and easy to get wrong, especially in festive weeks when kitchens fry in bulk. The food regulator FSSAI has clear guidance on when oil is still safe and when it must go. This guide turns it into simple rules for a home kitchen.

Quick answer

  • Oil with more than 25% total polar compounds (TPC) is unsafe.
  • Avoid reuse. If you must, reheat no more than three times, ideally once.
  • Throw out oil that smokes blue-grey, foams, darkens or turns thick.
  • Use leftover oil within a day or two and store it separately.
  • Never pour it down the drain.

What FSSAI says about reusing cooking oil

FSSAI’s Guidance Note 06/2018 on used cooking oil says oil with total polar compounds above 25% is unsafe and should not be used. TPC is a lab measure of how much the oil has broken down. You cannot see it at home, so the signs below matter.

The note advises avoiding reuse. If oil must be reheated, use it no more than three times, and ideally only once. The reason is that repeated heating forms trans fats and other harmful compounds. Also, you can read the FSSAI guidance note itself.

Signs your used cooking oil should go

Check the oil before every reuse. FSSAI lists these signs for discarding it.

  • Blue-grey smoke while heating.
  • Thick foam on the surface.
  • A dark or murky colour.
  • A change in consistency, so it feels sticky or thick.

If you see any one of these, throw the oil away. Also remember that strong frying, such as deep-frying namkeen at high heat, ages oil faster than light sautéing.

How to handle leftover oil safely

Let the oil cool fully before moving it. Hot oil causes serious burns, so never carry a hot pan across the kitchen. Then filter it to remove food particles, because burnt bits speed up the breakdown.

FSSAI says used oil deteriorates quickly. So households should use it within a day or two. Store it in a separate labelled container, never back in the fresh oil bottle. Also keep it away from flames and gas cylinders.

The note says filtered used oil can go into curry preparation at home. Also, this is gentler than frying again. Still, it should not be pushed beyond the limits above.

How to dispose of used cooking oil

Do not pour oil into drains or sewers. It blocks pipes and harms the environment. For small amounts, FSSAI suggests mixing the oil with an absorbent such as sand, sawdust, paper towels or food scraps. Then put it in the dustbin so it cannot spill.

For larger amounts, hand the oil to an authorised collector. Also, these collectors send it for biodiesel or other industrial use. Restaurants and sweet shops have extra duties. A business using more than 50 kg or litres of frying oil a day must keep records of use, disposal and the collecting agency.

Smart habits for festive cooking

Plan frying so you use fresh oil for the first batch and finish with a light item. For example, fry puris first and leave sweet items for the oil’s last life. That way, you reduce the number of reheating cycles.

Fry in smaller quantities to avoid leftover oil. Also keep the heat steady, since overheating speeds up damage. Our guide on how to read food labels in India helps you pick better oil in the first place.

If you see unsafe oil at a shop or stall, you can report it. See how to use Food Safety Connect to report unsafe food.

FAQ

How many times can I reuse cooking oil?

FSSAI advises avoiding reuse. If you must, reheat no more than three times, and ideally only once.

What is the TPC limit for used cooking oil?

FSSAI treats oil with more than 25% total polar compounds as unsafe. You cannot measure it at home, so watch for smoke, foam and dark colour.

How do I dispose of used cooking oil at home?

Mix small amounts with sand, sawdust or paper towels and put it in the dustbin. Never pour it down a drain.