If you are using your iPhone, find an app that will let you shoot and edit photos without applying a retro or lo-fi filter. Inventive's $2 Camera+, is a great app for food photography (and all photography, for that matter).
After you take the photo of your mom’s spaghetti, add the pre-set Food scene option—this will automatically warm up the colors in the photo and make them more appetizing. Another good effect to use in Camera+ is the Depth of Field option to blur out the distracting edges of your plate.
If you want a food-specific app, Vuzz's free Snapdish is a great option. It is a one-trick app, but it does its trick well, brightening up your food photo as “rare” for well-lit tables, “medium” for lower-light, or “well done” for dark restaurants. You can then upload the photo to Snapdish’s foodie map and send it straight to Facebook and Twitter. I took a photo of the same scene on my iPod Touch’s regular Camera app (left), on Camera+ with the food and depth-of-field filters on (middle), and with Snapdish’s “Rare” setting (right). The photos taken with the apps have more depth and the clean, warm colors are more appetizing.