What are preservatives?

Preservatives are substances that prevent the decomposition products and they’re in almost everything you consume. In your drinks, foods, cosmetics and even in your house. This has been happening for millennia. We use salt to preserve pork giving us ham, sugar to preserve fruits giving us jams and vinegar for kimchi and piccalilli. Alcohol is also a great preservative, creating a toxic environment for microbes to grow. So that bottle of unopened vodka will likely spoil (well not in your lifetime) and once opened it may lose some flavour but it takes years and years to go rancid.

Are they in low and non-alcoholic drinks?

Short answer is yes, as alcohol is not present there needs to be a preservative to increase the shelf life and quality of the liquids. Although on the face of it preservatives appear bad, as they are usually made in laboratories rather than natural extracts, many are vegan and approved the world over.