Allergen information labelling is a legal requirement for any pre-packed food or drink. It is important to make sure your label designs cover this requirement and provide your customers with the information they need to stay safe.
Allergens are classified into fourteen main categories that are regulated and must be declared on labels and packaging. These are as follows:
Obviously in the world of tea, most of these allergens are unlikely ever to be present even in the most unique of blends. Most of these ingredients wouldn't usefully transfer any flavour in infusion anyway, with the main exception being various types of nut.
If you do not stock any blends that contain allergens, then you only really need to think about labelling. It is still important to inform customers of the potential risk of contamination, with wording to indicate that the teas have been packed in a facility that also handles nuts. If more allergens are dealt with on your premises, then there will be further food safety steps that you will need to take to avoid contamination as well as additional precautionary warnings you will need to make.
When listing ingredients for products containing allergens, simply highlight any allergenic ingredients in bold and include any advisory warnings near the ingredients list.