In general, a food prep cook prepares food to be further cooked or combined with other ingredients. For example, in a casual dining restaurant like Bob Evans, a food prep cook:
* heats packaged soups and mashed potatoes
* makes packaged sauces, crepe batter, pancake batter, and waffle batter
* trays and bakes biscuits
* prepares scrambled egg mix
* chops greens and assembles the garden salad mix
* follows packaged instructions for the final assembly of ready made seasonal desserts like strawberry creamcheese pie
* Cleans, seasons, bakes, and hot holds baked potatoes
* Mixes, bakes, and holds meat loaf
* stocks cook work stations with all necessary ingredients and food supplies
The prep cook's job isn't that demanding provided the prep cook is organized and can anticipate the needs of the cook line. A good prep cook walks the line to see what supplies the cooks might be running low on. He then preps and holds these food products so that when the cooks run out, he can resupply them.
Line cooks have a more challenging job because they have to fill ticket orders. If the prep cooks have done their job and they have all the food supplies and ingredients they need, they have to knock out in-coming orders.
On busy days when there are fifteen tickets or more in the window with each ticket having 2, 3, and 4 orders, cooks have to keep their cool. They have got to work with a sense of urgency and they have got to be able to multitask.
Anyone can reheat the meatloaf made by the prep cook and plate it with mashed potatoes, corn, and gravy ... but when you've got three orders for meatloaf, four for burgers, 5 different types of omelets, 2 pancake orders, and 1 waffle to produce along with all the sides of crispy bacon, sasuage, whole wheat, rye, or white toast... and when a server is screaming at you because table 4 now has an add-on order ... you have GOT to keep your cool.
Food orders have to be expedited. Hot food has to go out hot. All of the food items on a specific ticket have to be produced and put in the window so that the server may serve all guests at a given table at the same time.
Working on the line can be a hot, sweaty, and stressful job with long hours and relatively low pay (especially compared to web development).
With this being said, line cooks make better money than prep cooks ... but the nature of their work is also more demanding.