The Whitbread pub chain, which found horsemeat in its food products, sees its share price fall after announcing a new test regime.
The slide occurred after the group said it would impose the new testing regime on all processed meats provided by suppliers and introduce a new system of certification.
Chief executive Andy Harrison said: "We have been dismayed by the recent discovery of equine DNA in two of our restaurant products.
"This situation is totally unacceptable and, as a leader within our industry, we are taking a wide range of actions to fix the problem and to ensure that it does not happen again."
Mr Harrison added: "Whitbread will also be working with the Food Standards Agency ( FSA ) to assist them in setting tougher standards and controls to apply right throughout the restaurant industry.
"This is not just a Whitbread problem, but a wider issue of quality control within parts of the processed meat supply chain, which supplies a number of restaurants and retailers."
The company operates the Beefeater, Table Table and Brewers Fayre pub chains.
Approached by Sky News, the FSA was unable to confirm what role Whitbread would take in any food regulation overhaul.
Whitbread also operates Premier Inns and Costa coffee outlets, and the new testing regime announcement comes as it revealed its latest group results.
The share slide occurred even though the company reported solid returns for most sectors.
Sales across the company rose 2.7% in the 11 weeks to February 14 and 16.9% for the 50 weeks to the same date.
Global sales at Costa were up 5.5% in the 11 weeks, with total system sales up 22% - to £962m - in the same 50-week period.
Costa's UK retail arm saw sales grow by 20.2% to £525m in the year, with like-for-like store sales up 6.6%.
The coffee group has reaped the benefits from consumer displeasure at US-based rival Starbucks, which was revealed late last year to have paid virtually no corporation tax.
Costa's rapid global expansion is also set to continue, with plans to open 320 new stores worldwide over the year, along with around 1,300 express coffee outlets.
It also plans to open a similar number of stores across the globe next year.
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