© Bloomberg/Abdrew CrowleyCEO of Tesco Philip Clarke
Philip Clarke, the chief executive of Britain's supermarket chain, admitted he could not promise that sweeping reforms to the company's supply chains would not leave customers paying more.
While he denied price rises were "inevitable", he acknowledged that he could not "guarantee" they would remain at present levels.
Publicly commenting for the first time since the food crisis erupted six weeks ago, he admitted that he had been left "shocked" and "appalled" by revelations.
He said horsemeat contamination was "wider than anyone imagined" and had been a "significant breach in trust" to his company's customers, which had been caused by "sloppy" suppliers "cutting corners for their own gain".
In a series of interviews, Mr Clarke announced a raft of reforms by the retail giant in response to the crisis.
He vowed to bring meat production "closer to home" and buy more produce from British farmers as part of sweeping changes to its supply chain.
He also promised fewer imports of meat from overseas, longer contracts with British farmers and a tough new system for testing products to ensure that customers were sure that what was on the label was in the packet.
He also said that from July all chicken meats sold at Tesco's UK stores will come from British farms. But he said he could not guarantee that families would not be forced to pay more for their food.
He told the BBC: "I hope that it doesn't mean price increases, but I can't stand here today and tell you that it won't. I hope it doesn't, I'll work to make sure it doesn't.
"I don't think it is inevitable. My job is to make sure that it doesn't. I cannot guarantee it but the instances of this contamination in our supply chain are so tiny."
He had earlier told ITV News: "I cannot guarantee that it won't cost more but our objectives should be that it doesn't.
"The reason I cannot guarantee [is] I am going to have to start put down new supply chains for these products and that is just what we are going to be doing in the months and years ahead.
"I don't know if it is certain. I can't make promises. All I can say is that the range of products that you see in a Tesco store are good, better and best."
From about 300 tested products, Tesco found three contaminated with horse, which was "far too many".
Speaking about horsemeat being found in Tesco products, he said: "It is appalling and I am as shocked as anybody else because I place great emphasis on the Tesco brand.
"We did not think for a minute that a supplier would introduce a third party agent.
"The [new] testing regime is intended to ensure that if it is not on the label it is not in the packet, if it is beef, it is beef, and nothing else."
He added: "And that is the most comprehensive testing regime I have ever seen, and it's happening right now. If it is not in the label it is not in the packing."
Mr Clarke will address the National Farmers' Union conference in Birmingham today, and said he hoped the changes he indicated were "good signs" of why customers should trust Tesco.
Shoppers have said they want more food from British farms on supermarket shelves in the wake of the horse meat scandal, a poll suggested.
Farmers called for more transparency and an end to "short-termism" in some sectors of the food supply chain and for better labelling so people could choose to buy British.
More than three in four people polled by the NFU said supermarkets should sell more food from British farms.
Ahead of the NFU's annual conference in Birmingham this week, president Peter Kendall said shorter and more traceable supply chains would alleviate the crisis of recent weeks.
He also called for clearer country of origin labelling so consumers could buy British more easily.
Comment: Translation: Further food price rises are inevitable and the food price rises in Europe so far this year are camouflaged by this contrived 'horse meat scandal'.