Yes, it is generally not recommended to store milk or any other food items in polythene (also known as plastic) bags in the fridge for several reasons:
Contamination: Polythene bags are not designed to be food-grade containers, and they can contain harmful chemicals and additives that may leach into the milk over time. These chemicals can pose health risks when ingested, especially if the milk absorbs them.
Spoilage: Polythene bags are not airtight, so they do not provide proper protection from air and moisture. Storing milk in non-airtight containers can lead to spoilage more quickly, affecting the taste and safety of the milk.
Bacteria growth: The porous nature of polythene allows air and bacteria to enter the bag, potentially leading to bacterial growth and contamination of the milk.
Environmental impact: Using single-use polythene bags contributes to plastic waste, which has significant environmental consequences. It's better to use reusable, food-grade containers to store milk and other perishable items.
Instead of using polythene bags, it's recommended to store milk in food-grade containers made of glass or BPA-free plastic, as these materials are specifically designed to be safe for food storage. Always ensure that the container you use has a tight-fitting lid to keep the milk fresh and safe for consumption. If you have concerns about the safety of your milk storage, it's best to consult with local health authorities or experts for specific guidelines.