Tooth extraction now i have bad breath odour something around the extraction site like a white colour think it's food could this be cause of smell ?

Unlikely: The whitish color around your extraction site is probably a blood clot. In the mouth, it's not hard and crusty like on the skin. It's softer and lighter in color. As far as the smell, it's possible you still have some residual infection there. Or, you might be getting a new infection there. Or, it might be unrelated. You should have your dentist take another look.

Tooth extraction: The white in the socket is the scab. Scabs in the mouth are white and on the skin they are black or brown because of the oxidation in the air. Rinse your mouth with warm salt water add one to two teaspoons of salt to a 16 oz glad and swish it around in the mouth to keep it clean. You can add some mouthwash to the mix to give you mouth a refreshed feeling. Good luck and feel better!

Could be infection: None of what you're describing sounds uncommon; it could be something very simple that you will solve with normal healing and good oral hygiene. However, you could have an infection and should speak with your surgeon right away. This is LOTS easier and safer to address sooner rather than later.

Return: You may have an infection. Return to the Dentist or specialist Oral Surgeon who did the extraction for a post-surgical examination.