McDonald’s chief executive has apologised to customers hit by an E. Coli outbreak in the US linked to the chain’s Quarter Pounders.

The outbreak, which has killed one person and hospitalised at least 10, has seen the company hit with a class action lawsuit amid flagging sales.

Speaking with investors yesterday, the company’s boss Chris Kempczinski said: “We are sorry for what our customers experienced.

“We offer our sincere and deepest sympathies and we are committed to making this right.”

One person affected by the outbreak described the pain he felt afterwards as like “knives in my stomach”.

Silas Mayes, 17, from Colorado visited the food chain with his father in early October. Three days later, Mr Mayes woke up with stomach cramps and was rushed to hospital.

Speaking to DailyMail.com, Silas said: “It was basically the worst pain I have ever experienced, like knives in my stomach.

“I would have these ongoing cramps every three minutes and it was just, like, this really sharp pain — it was unbearable. 

“I haven’t been able to pick up any of my hobbies again or anything because of how sick I’ve been.”

Tests later showed that he had been infected with the same strain of E. Coli as had been detected in his local McDonald’s outlet.

Last week, McDonald’s suspended sales of its Quarter Pounder burger, with officials believing that the chopped onions used in the meal were the source of the outbreak.

Three weeks on from the symptoms appearing, Mr Mayes’ mother says that her son is still not back to his old self.

Lera Davidson told DailyMail.com: “The major symptoms are gone, but the nausea and fatigue are still there. He is very weak.

“He was avidly working out before, but now he has lost 10 pounds.

“I don’t trust McDonald’s. We won’t be grabbing a McDonald’s burger or burger from anywhere anymore.”