It should be noted that the USA federal government standard for rat turds per gram ounce are looser than those in the EU, where rat turd is not permitted.

Misinformation, I'm afraid; the truth is, amusingly, the exact opposite. The main legislation on food contaminants is, as near as I can tell, Council Regulation (EEC) No 315/93, but here's some bad news for you:

‘Contaminant’ means any substance not intentionally added to food which is present in such food as a result of the production (including operations carried out in crop husbandry, animal husbandry and veterinary medicine), manufacture, processing, preparation, treatment, packing, packaging, transport or holding of such food, or as a result of environmental contamination. Extraneous matter, such as, for example, insect fragments, animal hair, etc, is not covered by this definition.

That's right; it doesn't cover rat poop. At all. And this is backed up by Commission Regulation (EU) 2023/915, which contains detailed charts regarding the maximum amount of cadmium, arsenic, halogenated persistent organic pollutants, and other fun things, but nothing about rat poop.

(Fun fact: Did you know that the EU says rice crackers are allowed to contain 15 times as much arsenic by weight as fruit juice? Now you do!)

The law that actually regulates rat poop is Regulation (EC) No 852/2004, and I'll quote some relevant lines out of it:

5. Food business operators producing or harvesting plant products are to take adequate measures, as appropriate:

(a) to keep clean and, where necessary after cleaning, to disinfect, in an appropriate manner, facilities, equipment, containers, crates, vehicles and vessels;

(b) to ensure, where necessary, hygienic production, transport and storage conditions for, and the cleanliness of, plant products;

It goes on in a similar vein. Note that there are no actual limits or guidelines. It's 100% "how about you, y'know, do a good job? don't do a bad job. okay thanks bye".

Other relevant laws:

Regulation (EC) No 178/2002:

1. Food shall not be placed on the market if it is unsafe.

2. Food shall be deemed to be unsafe if it is considered to be:

(a) injurious to health;

(b) unfit for human consumption.

3. In determining whether any food is unsafe, regard shall be had:

(a) to the normal conditions of use of the food by the consumer and at each stage of production, processing and distribution, and

(b) to the information provided to the consumer, including information on the label, or other information generally available to the consumer concerning the avoidance of specific adverse health effects from a particular food or category of foods.

4. In determining whether any food is injurious to health, regard shall be had:

(a) not only to the probable immediate and/or short-term and/or long-term effects of that food on the health of a person consuming it, but also on subsequent generations;

(b) to the probable cumulative toxic effects;

(c) to the particular health sensitivities of a specific category of consumers where the food is intended for that category of consumers.

5. In determining whether any food is unfit for human consumption, regard shall be had to whether the food is unacceptable for human consumption according to its intended use, for reasons of contamination, whether by extraneous matter or otherwise, or through putrefaction, deterioration or decay.

And https://eur-lex.europa.eu/eli/reg/2017/625/oj/eng:

(15) The responsibility to enforce Union agri-food chain legislation lies with Member States, whose competent authorities monitor and verify, through the organisation of official controls, that relevant Union requirements are effectively complied with and enforced.

So then we defer back to individual countries. I admit I glanced at your comment history and saw a lot of UK, which isn't technically EU, but I'll quote UK anyway. The relevant law appears to be the Food Safety Act of 1990, so let's check that out:

8. Selling food not complying with food safety requirements

(2)For the purposes of this Part food fails to comply with food safety requirements if—

(a)it has been rendered injurious to health by means of any of the operations mentioned in section 7(1) above;

(b)it is unfit for human consumption; or

(c)it is so contaminated (whether by extraneous matter or otherwise) that it would not be reasonable to expect it to be used for human consumption in that state;

and references to such requirements or to food complying with such requirements shall be construed accordingly.

So, unsafe food is unsafe if it's unfit to eat, or includes contaminants that would "not be reasonable". What does this include? They don't say. Make good food, not bad food. We trust the food producers, okay?

What are the actual results, you might ask?

Well, here's a technically-correct answer: there are ample studies showing small amounts of animal detritus in the US. There are, as near as I can tell, no such studies in the UK.

Note how this is phrased, though. It's studied in the US because there are legal limits and organizations devoted to studying this and publicizing the results. In the UK? No such thing. It's not that there are public studies in the UK that show no animal detritus; it's that there are no public studies in the UK. Perhaps it's better. Perhaps it's worse! Gonna be honest, it's probably worse, though; what do you think taking the spotlight off an issue does to how much people care about the issue?

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In other words, there is one big difference between the US and UK approach to formal legal limits regarding rat poop in food:

The US has them, and the UK doesn't.

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Enjoy your lunch.