Bear in mind that food poisoning isn’t free. It is not in society’s interest to have people off work sick, taking up medical capacity, and dying early. The advances in food safety over the 20th and 21st century was a great social good, and backsliding would be bad.
I do think that one problem, particularly in societies like the US where people don’t go to their GP very frequently, is that it’s pretty hard to measure impacts, because there’s little reliable data on mild (but economically impactful) cases.
The question should be: would lowering food standards make any difference?
Specifically in this case, in order to do a trade deal with a different continent, so the increased costs of transport are relevant.
I’m also told supermarket prices are very different from wholesale (and therefore import) prices. If so I would therefore expect any cost change to alter profit margins rather than family shopping bills.
Are you implying that the UK won't have enough food to feed itself post-Brexit, to the extent that it would need to import food from the US? I thought that the problem was that the US might insist on relaxing food safety regulations as part of a larger trade deal package. Do correct me if I'm wrong.
The question isn't the quantity of food, but the cost of food. There can be food aplenty, but if poor people need to spend a large amount of their income to acquire it, there will be a benefit to having a wider sourcing of cheaper food.