Since the group, who went to Ramalkalmedu in Idukki, cooked their own food, the police are clueless as to what caused the adulteration.
A 30-year-old person died and thirteen others were admitted to a hospital in Angamaly in what is a suspected case of food poisoning on Sunday.
Nearly 40-50 people of Danpur village in Banswara area had visited the temple in Sera village of the neighbouring state's Ratlam district.
On Thursday morning, 65 students of the school complained of uneasiness and vomiting after breakfast, following which they were rushed to the Princess Esra Hospital.
A 26-year-old woman on Sunday committed suicide by consuming food laced with poison that she also fed to two of her kids.
The children ate papaya on Thursday and later complained of headache, vomiting and an upset stomach, they said.
For record, 76 students from Bengal, came to the city on excursion by train on February 12.
The students of the school at Ita village in the age group of 6-7 year had 'prasad' after Saraswati puja.
According to the study, Salmonella sneaks in through a tiny gap created when a lateral root branches out from the plant’s primary root ther disease-causing bacteria that enter the root, fruit or leaf.
According to an official at the observation home the children had to be taken to the Indira Gandhi Institute of Child Health nearby the home after dinner as three children complained of stomach ache.
While six students were administered first aid, six others are being treated as inpatients at the local government hospital.
The Forensic Science Laboratory report of the Hulithotlu food poisoning incident is expected to arrive on Monday after which the exact cause of deaths of the four people can be ascertained.
On December 14, 15 people had died and more than 100 others were hospitalised after consuming 'prasad' distributed at Maramma temple in Sulavadi village.
Mahadeshwara Hill Saluru Math seer Pattada Immadi Mahadevaswamy was arrested and police told PTI said "he has a role" in the incident.
The guidelines apply to all the temples coming under the department. The department has also directed the temples to strictly follow guidelines issued in a circular issued in January 2012.