10 Trays and You’re an Expert!


A plate waste study is an inexpensive way to identify which fruits and veggies kids are eating. Plate waste collection is easier than you might expect. In Ohio, we say, “it only takes 10 trays and you’re an expert.” It’s that easy!USDA Infographic

Conducting plate waste studies at your school can help identify student preferences, aid in menu planning and ultimately reduce the amount of food waste. Plate waste studies can also help track trends like these:

  • % of fruits consumed
  • % of vegetables consumed
  • % of entrées consumed

Quarter-Waste Method

The Quarter-Waste Method was created by The Cornell Food and Brand Lab. Observers estimate whether all, 3/4, 1/2, or 1/4 of food was wasted. This coding process is reliable and comparable to weighted waste measurement (Hanks, Wansink, & Just, 2014).

Three Phases of a Successful Study

When you are ready to conduct your plate waste study, there are three phases to consider:

  1. Preparation
  • Schedule. Plan to be at the same school 2 to 3 days before and after the Smarter Lunchrooms intervention. Take a look at the school menu to find days when food items of interest are offered. Return on similar menu days for more accurate results!
  • Paperwork. Save yourself time by using the school menu to fill in food items that will be served. Leave blank rows for any last minute menu additions. We strongly encourage the use of Excel for data input.
  • Cafeteria Layout. Go into plate waste days with a plan! Think about where you want to set up the tray return area and estimate how many observers you will need for collection.
  1. Collection
  • Arrive Early. This will give you time to set up the tray collection area. Record standard serving sizes and observe what is being pre-plated for student lunches.
  • Code Food Items. Enter code data for food items that you can identify – look for food clues (crumbs) or wrappers and packaging. For specific coding entry information, download the plate waste protocol under the Evaluation Tools – Plate Waste tab above.

Below is an example of a tray you may see during your session. Can you code these items?

PW TrayIn this photo you can clearly identify baked beans and pineapple. The entrée is pizza, which can be identified from the plate it was offered on. The coding for this tray is:

  • Pizza = 0 (all of it is eaten)
  • Baked Beans = 0 (all of it is eaten)
  • Pineapple = 4 (all of it is wasted)
  • Milk = Unidentifiable through photography

To code the milk container, you can pull back the opening and visually see how much is left, or simply pick up the container and estimate by weight.

  • Clean Up. Make sure to clean up the collection area. Return the garbage cans and any items you may have borrowed. Thank the staff for their cooperation and help!
  1. Summary

Once you have your data, combine it to create a simple frequency table. A frequency table summarizes the percentage of each food item wasted and consumed. We have provided a downloadable waste summary template under the Evaluation Tools – Plate Waste tab above. Simply plug in your session numbers and see your results! If you are interested in a detailed waste report analysis, contact us. We’d love to help!

Share your reports with your school staff and school wellness committee members. Use the results to brainstorm solutions for menu planning and food waste reduction.

For additional resources, check out the videos provided by Cornell Smarter Lunchrooms on Organizing a Tray Waste Study Team and Tray Waste Practice. For more Smarter Lunchrooms plate waste resources, click on the Plate Waste page under the Evaluation Tools tab above.

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