There are two types of people in this world: organised souls who remember to bring 'bags for life' to the supermarket, and the rest of who struggle to open the fiddly plastic bags at the till, before our weekly shop comes crashing down the conveyor belt to drown us under a pile of baked bean cans.
But if you're one of the former, wipe that smug organic grin off your face - while those sacred 'bags for life' might be doing marvellous things for the environment, they could be harming your health.
Hugh Pennington, emeritus professor of bacteriology at Aberdeen University, warns that germs from raw meat can transfer easily to other foods. In the case of food that doesn't require cooking, such as fruit and vegetables, these germs can be easily transferred to people.
Speaking to BBC Radio 5 live's Drive Prof Pennington likens this use of 'bags for life' to preparing raw chicken on a chopping board, and then using it for vegetables or such like.
When pressed for a solution he tells the station: "Washing the bag is not a very good idea - you can't be certain you've got rid of all the bugs. For any bag that's has raw meat in it, I would recommend that bag is disposed of."
1. Sanitise your reusable bags with thorough washing -- machine or hand-washing -- with hot, soapy water. UA’s Gerba recommended doing this about once a week, depending on how often you use the totes.
2. Wrap uncooked meat, poultry and fish in individual plastic bags before placing them in the tote. This way you avoid possible contamination from leaky juices.
3. Who doesn’t love colour-coding? Pick one tote to always use for raw meat, poultry and fish -- fresh or frozen -- and pick another tote for produce and ready-to-eat foods.
4. Do not -- we repeat, do NOT -- store the reusable bags in the trunk of the car, whether they contain food or not. The hot temperature in there means it’s a nurturing home for bacteria; in fact, the UA study found that the large numbers of bacteria that tend to live in reusable bags can increase tenfold in a trunk within only two hours.
5. Don’t use your reusable bags for other purposes, like carrying your books or your dirty gym clothes (ew).
6. Clean wherever you usually drop your totes when you get back from the grocery (e.g., kitchen counter or table) to prevent cross contamination.
7. Store the reusable bags in a clean, dry place.