The company, which has alerted the Food Standards Agency, said the affected batches are Florette 100% Lambs Lettuce with use by dates of April 19, 20 and 21 inclusive.

Florette's brand is sold through the major multiples and a number of independent retail outlets in the UK. No other batches or products are known to be affected.

Soleco UK Ltd is implementing a full product recall of the affected batches and point-of-sale notices will be appearing in relevant stores.

Salmonella can cause diarrhoea and sickness. People who have already bought any of the potentially affected products should throw them away and take the packaging to their retailer.