A slaughterhouse under investigation by the RSPCA has admitted a former member of staff immersed two pigs in scalding water while they were still alive.
The RSPCA is to send an animal welfare inspector to Dalehead Foods in Linton, Cambridgeshire, after allegations were made in a local newspaper.
An RSPCA spokeswoman said: "Inquiries are still at a very early stage."
The company said it had terminated the employee's contract after two incidents which it claimed were "isolated".
The RSPCA spokeswoman said: "As I understand it, there is a three-stage process at the abattoir when the pigs are stunned, their throats are cut and then they are put in boiling water.
"This claim centres around the fact that pigs were put in the boiling water while still alive. An inspector plans to visit the site this week."
A spokesman for Dalehead Foods confirmed on Tuesday the incidents had taken place.
A statement said: "In May 2006 Dalehead Foods was obliged to suspend and retrain an employee who had not followed mandatory procedures at its site at Linton, Cambridgeshire.
"Following the report of a further breach in September 2006 by the same employee, Dalehead Foods invoked disciplinary proceedings, the outcome of which was the termination of the employee's contract.
"Further investigation has confirmed that these incidents are isolated.
"Dalehead Foods is committed to the highest standards of animal welfare.
"The Linton site operates to the RSPCA Freedom Foods standard in addition to being independently audited by a number of other factory accreditation bodies."