Although diners suffer from a disadvantage because they are not privy to what goes on in a food establishment's kitchen, Glen Rutherford, chief of the Arlington health department, has a few eater-beware suggestions:

* Look out for high-protein foods, such as meats, fish, milk, eggs and poultry that are not being refrigerated or heated properly in establishments such as carryouts or sandwich shops.

* Beware of the coffee creamer already on a restaurant table when you arrive, since it may have been sitting there in the danger temperature zone (45 to 140 degrees) for the danger time period (over three hours).

* Since bacteria are often transmitted via the human body, take note of restaurant personnel with poor personal hygiene.

Symptoms of foodborne illness can manifest themselves anywhere from 2 to 48 hours after a contaminated food has been eaten, says Rutherford. (The time variables depend on the bacteria involved and the resistance of the individual.)

Foodborne illness symptoms, which are frequently indistinguishable from intestinal flu, include diarrhea, vomiting, abdominal cramps and possibly fever. One obvious distinguishing feature, however, is when more than one person who ate the same food becomes ill, Rutherford added.

If you suspect that you have contracted a foodborne illness, call your doctor. In addition, report it to the local health department:

District: 673-6736.

Arlington: 558-2661.

Alexandria: 838-4880 or 838-4855.

Fairfax County, Falls Church City and Fairfax City: 534-0343.

Montgomery County: 251-7272.

Prince Georges County: 794-6800. Ext. 217.