The Centers for Disease Control and Prevention (CDC), has issued a warning especially to those over 50 to reheat their cold meat before consuming as a way to prevent listeriosis.
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Listeria may not be as common as Salmonella or E.Coli but is lethal. The CDC recommends that any opened pack of sliced meat should be chucked out within 5 days.
Cold meat in the fridge is ideal for the bacterium, Listeria monocytogenes , to reproduce.
Listeria needs urgent medical attention as it can turn life threatening in certain cases.
Source-Medindia