Some own-brand sesame seed products sold by Asda, Co-op, Tesco and Waitrose have been recalled because of the presence of salmonella, a bacterium that causes food poisoning.

Customers contacted the Post after seeing a recall notice for the seeds on tills at Co-op's Downend store.

Asda are recalling their 150g Whole Foods Sesame Seeds with best before dates of September 2009, October 2009, November 2009 and December 2009.

Co-op are recalling their 100g Sesame Seeds with a best before date of January 2010. Tesco are recalling their 300g Wholefoods Sesame Seeds, their 300g Wholefoods Three Seed Mix and their 100g Sesame Seeds.

Waitrose are recalling their 100g Sesame Seeds with best before dates of February 2010 and March 2010.

All stores are offering a full refund for the seeds. For more details contact Asda on 0500 100 055, Co-Op on 0800 0686 727, go to your Tesco Customer Service Desk, and Waitrose on 0800 188 884.

A spokesperson for the Food Standards Agency said: "Point-of-sale notices will be displayed in stores, explaining to customers the reasons for the recall and the actions they can take if they have bought an affected product."

A spokeswoman for the Co-op in Downend said: "The Co-op, in conjunction with the Food Standards Agency, has recalled its own brand sesame seeds as a precautionary measure."