The UK’s Food Standards Agency has widened its investigation into poultry processor 2 Sisters Food Group to encompass 13 plants, including the West Bromwich site in the Midlands that has come under scrutiny over hygiene.

An FSA spokesperson confirmed the number of sites involved to just-food today (6 October) and said the inspections are expected to be completed in the “next couple of weeks”. The UK authority is also working closely with Food Standards Scotland who are “increasing the level of their unannounced inspections programme as a precautionary measure”, the person added.

A joint undercover investigation by The Guardian newspaper and ITV News aired on television late in September showed workers apparently tampering with slaughter date labels on fresh chickens at the firm’s West Bromwich plant, posing a potential health hazard to consumers over use-by dates. 

Major UK supermarkets immediately suspended chicken supplies from the plant. 2 Sisters responded by temporarily closing the facility in what it said on 1 October was due to some “isolated instances of non-compliance” with its own quality management systems. 

The Guardian/ITV probe also appeared to show workers mixed birds with different “kill” dates on the production line along with poor hygiene controls. The investigation alleged that chickens returned by UK supermarkets to 2 Sisters were repackaged and returned.

After launching an immediate investigation into the allegations, the FSA said on 29 September it found “no evidence of breaches” at the West Bromwich site.

In an update earlier today, the food authority said in a statement: “This inspection has not identified food safety issues on these premises, but it highlighted issues requiring management attention, for example in relation to some aspects of staff training and stock control. We are working with the major retailers supplied by 2 Sisters, as well as reviewing information from various other sources.”

Heather Hancock, chairman of the FSA added: “Consumers deserve food they can trust, and can be reassured that we take allegations of poor practice very seriously. Although our initial inspection found no risk to public health, we are broadening our investigations until we are satisfied that this is truly the case.” 

2 Sisters announced on 3 October it had “found some other areas of concern” at the plant. It said the problems related to food hygiene rather than regulatory breaches. 

Martyn Fletcher, the company’s COO, said in a statement that day: “We do not believe that we have got any major compliance issues in our organisation. It’s isolated to this particular video footage and we have, in investigating the site, found some other areas of concern at that site.”