The number of victims of the food poisoning incident at Sekolah Menengah Sains Tapah has risen to 63 people as compared to 58 yesterday.

Health Minister Datuk Seri Dr S. Subramaniam said of the total, 25 were still warded at the Tapah Hospital, 10 discharged while the rest received outpatient treatment.

"We are waiting for the results of tests on food samples taken to identify the cause of the food poisoning," he told reporters after visiting the Taiping Hospital here today.

On Saturday, 43 students and a teacher came down with food poisoning after they were believed to have had supper consisting of "roti jala" and chicken curry at the dining hall of the school's hostel.

Dr Subramaniam said his ministry would work closely with the Education Ministry in monitoring food quality at school canteens and hostel dining halls.

In conjunction with the visit, Dr Subramaniam also opened the Clinical Services Block of the hospital, construction of which was fully completed on May 21, 2014 at a cost of RM189 million.

In IPOH, Perak Health director Datuk Dr Juwita Ghazali said the way raw chicken was kept and too short a cooking time were identified as the causes of the food poisoning.

Dr Juwita said this was arrived at through the Hazard Analysis Critical Control Point (HACCP) methodology.

"Storage of raw chicken was unsatisfactory, the meat was not frozen at -6 degrees Celsius for 32 hours, from 10.30am (April 1) to 6pm (April 2).

"This caused an exponential growth of Salmonella bacteria leading to the food poisoning," she said in a statement here today.

She added that the chicken was only cooked for 30 minutes in preparing the gravy for the "roti jala".