Hot food has a line too. It's 135°F, and your steam table has to hold it.

Under the FDA Food Code, the model most state health codes follow, hot food held for service has to stay at 135°F or above. Below that, bacteria grow faster.

Food that's being reheated to hold has to reach 165°F within two hours first. Your local health department sets the details, so check its rules for your stores.

A steam table or warmer keeps hot food hot. It isn't built to bring cold food up to temperature. Food that goes in cold can sit in the danger zone for too long while the unit slowly warms it.

Cook or reheat food first, on the range, in the oven or in the steamer. Then move it to the steam table.

• Preheat it. Turn it on early enough to be hot before the food goes in.
• Keep the water at the right level. Too little and the element can burn out. Check it through the shift and top it up with hot water.
• Use lids. Covered pans hold heat far better than open ones.
• Stir. Food on top cools faster than food at the bottom.
• Check food temperatures with a thermometer every two hours, and write them down.

At close, turn the unit off and let it cool. Drain the water, wipe out the wells and dry them. Hard water leaves scale on the elements, so wipe away any white crust.

Keep a screen over the drain so food doesn't clog it. A clogged drain makes the unit hard to empty and clean.

Heated holding cabinets and strip warmers follow the same 135°F rule. Check that the door closes and the gasket seals. Check the water pan, if the cabinet has one, at every shift. Put a thermometer inside to make sure the dial matches the real temperature.

• Food falls below 135°F even with lids on and the water right.
• One well runs hotter or colder than the others.
• The unit takes much longer to heat up than it used to.
• The water boils hard on a low setting, or won't heat at all.
• The breaker trips, or the unit leaks.

A failing thermostat can stick on as well as off. A unit that boils dry on a low setting needs a look before the element burns out.