Typically a clogged food trap will smell more like rotting food or methane, but a metallic smell may nonetheless be caused by an issue in the food trap. The food trap is typically a small metal or plastic screen that covers the drain opening and catches large food particles and utensils, preventing them from passing down into the drain hose and causing a clog. Inspect the trap to ensure there are no utensils or clogs causing your issue.
The inside of the dishwasher can be cleaned using ordinary household vinegar. Pour 2 cups of vinegar in a measuring cup, and set it on the bottom rack of the dishwasher. Turn the dishwasher on, and allow it to run through a full cycle. The vinegar is a mild acid and will break down the bonds of any mold or mildew that may have accumulated in the unit, which may account for the odor.
Citric acid crystals can be purchased from most home improvement stores and can be used to clean the inside of stainless steel dishwashers. Stainless steel can gather a thin film of mold or mildew that feeds on food particles. Citric acid crystals will help scrub the inside of the unit of any such buildup.
The snaking, curved piece of metal at the base of your dishwasher is a heating element. Ensure there are no breaks or bends in the bottom rack of the unit that may be leading to metal coming in contact with the element. See that there are no utensils trapped between the element and the dishwasher floor, and look for any signs of element malfunction, such as burns on the floor of the dishwasher or bottom rack. Repair or replace the element as needed.