A national outbreak of Salmonella that has affected 156 people is being investigated, Public Health England said.
The cases in England "occurred in isolated clusters over several months" and have been managed locally, according to the health watchdog.
However, the cases of Salmonella "are now being reassessed as potentially linked under a national investigation," it added.
More top news
Around 40% of workers admitted to working despite being too sick for the office, a survey has revealed.
High street stores con customers by offering "discounts" which offer little to no savings - and may end up costing more, Which? has claimed.
Britain has claimed victory over Germany in a special football match marking 100 years since the near-legendary WWI Christmas truce match.