The perpetrator is said to have laced the food with ethylene glycol, a sweet tasting substance commonly found in antifreeze.
The man, believed to be in his fifties, sent a disturbing email to several supermarket and pharmacy chains threatening to contaminate more food they coughed up a hefty ransom.
The message revealed he had already poisoned five jars of baby food.
Officers in Friedrichshafen, southern Germany, rushed to remove every container baby food from shelves across the city after learning of the threat.
And they have urged the public to be on the look out for food containers which may have been tampered with.
Local police chief Uwe Stürmer told a press conference today: “This is an exceptionally severe case of extortion and we have to assume we dealing with a very ruthless extortionist who is prepared to kill.”
The Telegraph reported detectives said the perpetrator had demanded at least €10million (£8.8m) in ransom.
Officers have identified a man they believe to be the suspect.
He was spotted on CCTV recordings wandering supermarket aisles with an empty basket dressed in a white beanie, glasses and a black leather jacket.
Reuters said authorities in the southwestern state of Baden-Wuerttemberg were planning to step up checks of food on sale, but had warned the public identifying contaminated items would be difficult.
“The case is difficult because the blackmailer did not say which food will be targeted or what poison he will use,” a consumer protection official told the news agency.