Visitors to this year's Royal Welsh show are being warned to check for symptoms of bacterial infection after unpasteurised cow's milk was distributed at the show.
The milk produced at Penlan y Môr Farm near New Quay has been linked with four cases of Campylobacter.
Public Health Wales, Hywel Dda University Health Board, the Food Standards Agency and Ceredigion County Council are currently investigating.
Symptoms of Campylobacter infection include persistent nausea, diarrhoea, stomach cramps, and fever.
People with weakened immune systems are particularly vulnerable to food poisoning, and are advised not to consume unpasteurised milk or cream. Vulnerable groups include pregnant women, infants, children and older people.
If you have consumed Penlan y Môr unpasteurised milk any time since 1 June, including at the Royal Welsh Show on Wednesday 26 July, and you are experiencing symptoms of Campylobacter infection, we want to hear from you. The symptoms of Campylobacter are persistent nausea, diarrhoea, stomach cramps and a fever. Sometimes vomiting and bloody diarrhoea may also develop. It is a very unpleasant infection, and more serious complications can occur. As in any diarrhoeal illness, washing hands after using the toilet and before preparing or eating food is very important and anyone worried about their symptoms should seek medical advice. We will continue to monitor the situation.