'Non-lactose fermenting bacteria' was found in the samples of fermented soyabean, a delicacy of the north east.
A number of people working in the SCERT office in Aizawl purchased fermented soyabean from an employee on July 18.
Of them at least 30 were taken ill and 14 were hospitalised till date, the sources said.
The same bacteria was found in the fermented soyabean eaten in south Mizoram's Bungtlang south village in May where 90 people were taken ill, the sources added.
The bacteria could be created by unclean and unhealthy processing of the soybean while preparing for fermentation, said Dr Pachuau Lalmalsawma, Nodal Officer of the Integrated State Disease Surveillance Programme.
The sources said the bacteria could cause diarrhoea and other complications.