There is more food law in the UK than anywhere else in the world in cluding the US. The main bits for your question centre of the following.
The UK Food Safety Act.
The main responsibilities can be summarised as:
• to ensure you do not include anything in food, remove anything from food or treat food in any way which means it would be damaging to the health of people eating it
• to ensure that the food you serve or sell is of the nature, substance or quality which consumers would expect
• to ensure that the food is labeled, advertised and presented in a way that is not false or misleading
Main catch all on food safety, including food contact equipment and its hygiene is section 7. Essentially food contact surfaces must be smooth, impervious and intact. The offence covers physical, chemical and biological contamination. These are the 3 main elements of hazard analysis risk assessment required under international codex and referenced in the Unified European Food Safety Directive (below). There is also another nice legal catch all "Producing / selling food not of the nature substance or quality demanded". As a final touch it is one of the few pieces of UK legislation where you are guilty of an offence unless you can prove otherwise. To allow this 'proof' to be presented there is the 'defense of all due diligence and all reasonable precautions', main bit for your question is:
7 Rendering food injurious to health. - copied text from the act.
(1)Any person who renders any food injurious to health by means of any of the following operations, namely—
(a)adding any article or substance to the food;
(b)using any article or substance as an ingredient in the preparation of the food;
(c)abstracting any constituent from the food; and
(d)subjecting the food to any other process or treatment,
with intent that it shall be sold for human consumption, shall be guilty of an offence.
(2)In determining for the purposes of this section and section 8(2) below whether any food is injurious to health, regard shall be had—
(a)not only to the probable effect of that food on the health of a person consuming it; but
(b)also to the probable cumulative effect of food of substantially the same composition on the health of a person consuming it in ordinary quantities.
(3)In this Part “injury”, in relation to health, includes any impairment, whether permanent or temporary, and “injurious to health” shall be construed accordingly.
178/2002 EU Food safety Directive
this lays down the general principles and requirements of food law, main part of interest to you will be:
Article 14 - sets out 'food safety requirements': in particular that food shall not be placed on the market if it is unsafe. It is deemed to be unsafe if it is considered to be injurious to health or unfit for human consumption. (was originally section 8 of the UK food safety act)