HEALTH experts are warning caterers not to use imported eggs from Spain.For they have been identified as the source of salmonella outbreaks around Greater Manchester.Hundreds of catering firms in the region are being contacted as part of the alert.It follows four outbreaks of salmonella in Greater Manchester and Cheshire this year been linked to contaminated Spanish eggs.The imported eggs are not subject to the same rigorous checks as those produced on farms in Britain. The North West Health Protection Agency (HPA) has teamed up with the Food Standards Agency (FSA) after a national outbreak team identified at least 2,000 people nationwide who contracted salmonella from Spanish eggs in the last two years. Experts believe the true figure may be as high as 6,000.