Public Health Wales says it is working with the Food Standards Agency and environmental health officers from Swansea, Neath Port Talbot and Carmarthenshire to investigate the outbreak.
We know that the majority of cases have eaten laverbread produced by Penclawdd. The company has cooperated fully with our investigations and has chosen to voluntarily withdraw the product from sale as a precaution.
Laverbread is generally a safe product to eat, and it remains unclear whether it is indeed the source of this outbreak.
However, given that we cannot rule out laverbread at present, it is very important that, to avoid the risk of illness, anyone with this product at home does not eat it.
Anyone who is concerned about their health should contact their GP or call NHS Direct 0845 4647.
More top news
RAF veteran Andy Davies says the Royal British Legion helped him get back on his feet after problems with alcohol.
Lucy has the latest weather forecast for Wales
Plaid Cymru leader Leanne Wood has said her MPs won't back English votes for English laws until Wales gets an extra £1.2 billion a year.