12th Century food hygiene
Although a 12th Century kitchen and eating table may appear quite unsanitary to our modern eyes, in fact we can document a number of procedures in place to deal with this issue.
In the kitchen
A garderobe pit was located in the kitchen of a house (well at least any house large enough to have a kitchen). Into this food scraps were disposed of.
Food was also preserved in a variety of ways to make it less susceptible to the nasty organisms that make you sick.
Special places in the kitchen were set asside for jobs such as plucking and cleaning fowl. (Holmes 1952, p93)
Some cleanliness standards for food servers (and presumably cooks) are present in the literature - a server carving a roast gets into big trouble when he is accused of wiping his mouth and nose while carving. (Holmes 1952, p90). From this we can infer that quite strict cleanliness standards could be expected in the kitchen and infringements of these might be punished severely.
At the table
Diners would wash their hands before eating. In monasteries a whole large row of basins could be dedicated to this purpose (ZV), in houses basins and towels might sit on a sideboard for the use of diners, and richer persons at more formal occasions might have servants cary around basins, ewers of water and towels. (Holmes)
In the 16th century etiquette rules stated that one hand was to be used to take food from the communal dish to your plate or trencher and the other hand to bring food to your mouth. Similar rules are expected at 12th Century dining tables.
Etiquette rules are quite insistent on matters of cleanliness - washing your hands so your hands and nails are clean, no touching the nose or ears while at the table, no using toothpicks, and to wipe your mouth before using the hanap (a ceremonial communal drinking vessel)(Holmes 1952, p89)
Food scraps were kept in your bowl. Bones were also to be kept in the bowl or thrown on the floor for the the dogs. (Holmes 1952, p89)
Various records exist that stress the importance of having access to clean water to the 12th Century person. A supply of fresh water would be kept in the kitchen of a townhouse for the use of the house.