The Food Standards Agency has warned that bags for life pose a food poisoning risk if they are used to carry raw foods such as meat and fish.
It warned that even if there is no leakage from foods, packaging can harbour traces of harmful bacteria that can cause stomach bugs and said shoppers should have separate bags for raw foods, ready-to-eat foods and household items such as detergent.
In an updated post said: "Always check your bags for spillages (for example raw meat juices or soil) after every use. If there has been visible spillage, soiling or damage, plastic bags for life should ideally be used for another purpose (where no safety risk will occur) or replaced. Even if there are no obvious spillages or staining after several uses, we would recommend that cotton/fabric bags for life be machine-washed regularly if they have been used for carrying raw items."
Free carrier bags were banned in Scotland in October 2014.