The figures come despite consumers suggesting they would be happy to eat the product in future.
Further research has found a significant number of consumers would be happy to eat horsemeat providing it was "safe" and properly labelled.
Retail analyst Kantar Worldpanel found that consumers changed the products they bought following the food scandal, which broke on January 16.
Director Edward Garner said: "The issue has so far only affected the performance of individual markets rather than where consumers are choosing to shop. For the four weeks ending February 17, frozen burger sales were down 43% and frozen ready meals declined 13%, demonstrating a change in shopping habits."
Separately, a survey of almost 14,000 meat-eaters found 51% would buy horsemeat as long as they knew it was bred for eating and was therefore safe.
Of those who said they would eat horse, 29% said it would need to be cheaper than beef. However, 48% said they would refuse horsemeat outright, even it if was free, consumer website moneysaving expert.com found.
Meanwhile, traditional beef pies have been taken off the menu by Aberdeen FC in the wake of the horsemeat scandal after its supplier, Sodexo, took the decision to withdraw its beef products as a precaution.
Scotland's head of the Food Standards Agency described the horsemeat scandal as a "wake-up call" to the food industry.
Director Charles Milne said the watchdog was working hard to restore the public's confidence in food.
Mr Milne described the incorrect labelling of meat products as a "huge breach of trust".
He said: "I think this has been a real wake-up call for the food industry in terms of its responsibility to consumers.
"This is a really serious issue. While it is not a health issue, it is really serious."