A stomach virus has spread through several towns of the Stavropol Territory since last Wednesday, and prosecutors said 377 children and 48 adults are being treated in hospital.
A preliminary probe carried out by Russia's consumer rights watchdog revealed that the infection may have been caused by dairy products produced by the local Vita company, which has been banned from further operations.
Prosecutors said two inspections of the company's facilities conducted by the federal regulator in 2006 and 2007 had exposed violations of food safety standards and resulted in administrative reprisals for several top managers. However, Vita's activities were never suspended.
Prosecutors are now investigating the work of the local consumer watchdog officials.
This is the fourth outbreak of the infection in the Stavropol Territory to date. Over 500 people were affected by food poisoning in the region from July to September.