As a High School Head Cook here at Mott High School in Warren Michigan, we are moving our operation to more fresh potatoes and there have been some (sometimes heated) discussions on how to clean potatoes.  I would surely appreciate your recommendation.  Thanks for your time and consideration.

Here are a few tips to think about when washing potatoes. Since potatoes grow in dirt, they do need to be washed at some point when harvested out in the fields. We try to keep the dirt on till the potatoes come out of storage, as washing them immediately might trap moisture in the eyes of the potatoes and create a musty or mold smell while stored. Once the potatoes are trucked into the shipping facility they are typically “flumed” in water along the conveyor belts to get rid of any dirt or sand and minimize bruising. Then the potatoes are allowed to dry. However, sometimes not all the dirt gets removed or the water may still have some particles that end up on the potatoes when boxed up for shipment to customers like your school.

So, the first recommendation is to wait to wash the potatoes till the last moment before using. Don’t do it too far in advance. There is no need to wash in a solution of bacterial soap or veggie wash. The magazine, Cooks Illustrated, did find with some fruits and vegetables that an acidic solution of vinegar and water helps disinfect, but scrubbing was pretty effective too. There's also this article from NPR. 

For quantity washing I usually dump the potatoes from the carton into a large clean metal sink, fill with water and walk away. Much of the dirt will fall to the bottom. Come back, drain the sinks and rinse the potatoes before pulling them out to scrub.

Washing should include some scrubbing to get any dirt lodged in the eyes of the potatoes. Since most Idaho potatoes are grown in a sandy or volcanic soil and not clay based, the scrubbing can be pretty minimal. At the beginning of the season, you’ll note that scrubbing is like sandpaper, it will take a lot of the protective skin covering off. So handle gently.

Let the potatoes drain in a sink or colander before putting away, so they are not wet.

Note… in the olden days (when I worked in a kitchen) you could put the potatoes in a flat tray for silverware and run just the rinse cycle in a commercial dishwasher. This is no longer recommended, as there may be residual soap in the system and often the machines now have tubes automatically dispensing liquid soaps and rinse agents.  For parties at home for large crowds I have still done this, just ran the dishwasher without any rinse solution or soap. But it’s not the way to do it correctly now.

You mentioned cutting the potatoes in half when preparing them and I would assume you bake and serve them plain with a little oil coating or plain and top with yummy ingredients that kids love such as chili, melted cheese and broccoli, salsa, etc.

If you wash the potatoes, then cut the potatoes in half and coat with oil then place face down on sheet pans for baking later, you can skip this next step.

When you wash, try this to keep the inside from oxidizing or turning brown like a cut apple. Dip the halves in a water and lemon juice concentrate of one gallon water to one tablespoon concentrated lemon juice.

Hope this helps you end up with delicious tasting baked potatoes.