I'm interested in pretty much any period and place before germ theory was applied to food borne illnesses. Are there any records of cleanliness standards in the kitchens of royalty (or anyone else obscenely rich)? Would pots have regularly been washed? Did people bother to clean a knife they had used to slice raw chicken, for instance, before they used it to slice raw fruit or vegetables? Was there any awareness that food needed to be heated a certain amount or it could make you sick?
I'm aware of some records of well known deaths from food poisoning, is there any indication of how common it was in the general population?
I can't speak to the history of pre-grem theory kitchens but I do know health codes. The answer is no. The health code is so specific in it's terms and regulations there is no possible way for any kitchen before germ theory was accepted to pass. I will quote NJ regulations because that is what I am most familiar with, but they are typical for most of the US.
Example:
8:24-2.1 Supervision
(b) Based on the risks of foodborne illness inherent to the food operation, during inspections and upon request, the person in charge shall demonstrate to the health authority knowledge of foodborne disease prevention, application of the Hazard Analysis Critical Control Point (HACCP) principles, and the requirements of this chapter. The person in charge shall demonstrate this knowledge by substantial compliance with this chapter.
Definitionally all pre-germ theory kitchens would fail because someone in charge needs to understand germ theory.
Wide spread use of industrial refrigeration did not occur until slightly after Pasture's experiments. A pre-grem theory kitchen is going to fail on many points of perishable food storage for not maintaining a low temperature or holding food at the proper high temperature.
(f) Except during preparation, cooking, or cooling, or when time is used as the public health control as specified under (g) below, potentially hazardous food shall be maintained:
At 135°F or above, except that roasts cooked to safe cooking temperatures or reheated as specified under N.J.A.C. 8:24-3.4(g)5 may be held at a temperature of 130°F; or
At refrigeration temperatures.
and
"Refrigeration temperatures" mean:
- 41°F or less, except as specified under 2 below.
The health code goes on to specify the requirements of a three compartment sink, the types of chemicals or heat required for sterilization, vent hood requirements, fire suppression, cleaning rates, labeling requirements, holding temps, plumbing, water supplies, the definition of 'smooth' and on and on. A modern home kitchen is unlikely to pass, even if you ignore the requirement that professional kitchens cannot be in a private home. NJ health code is available here, if you want find out how hard it is to pass even if you are trained in modern food handling.
As others have said, older kitchens would fail inspection, as there are regulations that older kitchens simply wouldn't have met. But, to address your examples:
Du Fait De Cuisine, a manuscript from 1420 has fascinating instructions for preparing a banquet. Nothing that I could find talks about dealing with raw chicken in particular, but the word "clean" is repeated over and over and over (go to the above link, and do a search on the page for "clean" to see how often it occurs). Also, on the list of required personnel are "half a dozen scrubbers to clean the sideboards and the cutting boards"
Also, from the Cook's prologue in the canterbury tales:
"you have peddled many a Jack of Dover
When twice already you had warmed it over.
There's many a pilgrim wishes you Christ's curse;
Your parsley has them feeling all the worse
(They ate it with your stubble-nourished goose),
For in your shop so many flies are loose."
So, there certainly was the understanding that unsanitary food caused illness, and that cooks bore the responsibility for people getting ill from the food they prepared.
The body also develops an immunity to common bacteria or other contaminants when exposed to it enough. This is why Americans don't usually fare well with tap water in parts of Mexico and India (for example), but the locals do.