"As of 14:00 Moscow time (10:00 a.m. GMT), 96 people have been brought to hospitals in Moscow. Another 55 workers have been taken to hospitals near Moscow," the department said, also confirming earlier reports that six patients remained in a serious condition.
Initial reports on Tuesday morning suggested that 74 people had fallen ill.
The Federal Service for the Oversight of Consumer Protection and Welfare, which is investigating the incident, said food delivered for the workers was to blame, but added the source of an infection and the infection itself were still to be identified.
"A source of the infection ... and the place where the food was cooked are being clarified," the agency said.
It also said all the patients were suffering similar symptoms: high temperature, nausea, vomiting and diarrhea.
A police source earlier said experts had suggested the workers could have contracted salmonella poisoning, a potentially lethal infection that affects the gastrointestinal system.
The emergencies ministry said earlier the first patients had arrived from a construction site on Tverskaya Street just a few steps away from Red Square and the Kremlin.
The ministry said the workers were from Turkey and former Soviet republics, the main source of cheap workforce for numerous construction projects in booming Moscow, many of which are implemented by Turkish firms.
