More religious Jews stick to a series of strict dietary laws. These kosher laws include: not mixing dairy and meat (e.g. no cheeseburgers), only eating land animals that chew their cud and have cloven hooves (e.g. no pork), not eating scavengers (e.g. no vultures), only eating meat that has been washed in a salt bath and has had all traces of blood removed, and only eating sea creatures with both fins and scales (e.g. no shellfish or bottom feeders).
Limited supplies of Kosher foods can be bought at Davis Supermarkets, but people with cars can benefit from the larger selection at Bob's Butcher Block & Kosher Deli in Sacramento. Foods that are kosher can often be identified by a symbol on the packaging usually consisting of a U inside an O "OU" or a K in a triangle or star.
Local Kosher Sources and Items
To add to this list, simply add ["Certified Kosher"] in the entry about the establishment
If you're preparing a traditional Ashkenazi (Eastern European) meal, but don't care about Kosher laws, the Davis Food Co-op sells chicken fat for $.39/lb. It's easy to render into shmaltz, tasty, has no trans-fat, and 1/2 the saturated fat and 1/3 the cholesterol of butter!
A popular baked good historically associated with Jewish cuisine is the bagel.