Six people were hospitalised in Egypt's coastal city Alexandria on Monday, after they ate badly preserved "fesikh", a traditional dish of pickled tilapia fish, according to the Ahram Arabic news website
Fesikh is traditionally eaten on Shem El-Nesim, a millennia-old celebration of the beginning of spring, that is today a national holiday in Egypt.
Its preparation involves steeping the tilapia fish in vinegar for up to one year. If not prepared properly, it can easily cause food poisoning.
Magdi Hegazy, a deputy at the health ministry, said that all hospitals in the coastal city had made the necessary preparations to receive emergency cases.
Today, Shem El-Nesim is celebrated on the Monday that follows Coptic Christian Easter.