Members of the board of the Food Standards Agency (FSA) have been told to declare any contact with its former chief executive and Tesco group technical director Tim Smith.

Board members were ordered last year to declare contact for a two-year period following Smith’s unprecedented move from the watchdog to the retailer last year.

Emails from the FSA’s outgoing chairman Lord Rooker to board members obtained under the Freedom of Information Act reveal Smith’s switch forced it to “strengthen its governance arrangements”, The Guardian reported.

Smith, who has extensive food supply chain experience with Arla Foods and Northern Foods among others, moved to Tesco on October 15. Rooker noted Smith’s “transition from UK food regulator to Tesco has passed with minimal comment” and that “Tesco is not any old British company” in emails.

Rooker said: “Depending on which list you look at it is the third-largest UK employer (after the NHS and the Ministry of Defence), top own-label supermarket, top UK market share in supermarkets, fourth in best retail brands and 24th in global brands. That is enough on how good and big they are.”

The Advisory Committee on Business Appointments advised Prime Minister David Cameron to approve Smith’s move and recommended that Smith should not become personally involved in lobbying the UK government on behalf of his new employer for two years.

There is no suggestion of wrongdoing by Smith who told the FSA he was on the hunt for a new position in May last year and was monitored by three FSA members.

After landing the Tesco job in July, he stepped back from the FSA board in August and continued receiving his £140,000 a year salary until he left in October.

Tesco said: “Tim Smith was appointed to his role as group technical director at Tesco in accordance with the rules set out by the Advisory Committee on Business Appointments. Tim Smith is fully aware of these rules and has abided by them throughout his time at Tesco.”