The Food Standards Agency has called for UK food manufacturers to test all processed beef products following the horse meat scandal which has shocked the food industry.

Retailers and suppliers are examining their supply chains closely after a third-party French supplier alerted manufacturer Findus to concerns that the beef lasagne product did not “conform to specification” earlier this week.

The Food Standards Agency (FSA) said Findus had found 11 beef lasagne meals in which it contained between 60% and 100% horsemeat in a test of 18 products.

Findus withdrew from sale or destroyed 380,000 beef lasagnes as a result of the findings.

The FSA said: “There is no reason to suspect that there’s any health issue with frozen food in general, and we wouldn’t advise people to stop eating it.”

Last month, Irish food inspectors revealed they had found horsemeat in some burgers stocked by retailers including Tesco, Iceland and Lidl.

Suppliers in Ireland, Poland and France have all been implicated as the source of the horse DNA.