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University Dining Services has worked closely with the Greening Dining student group since 2002 in an effort to adopt more sustainable practices. The University continuously explores new procedures and expands campuswide education about sustainable dining.

Figure 5: Food Purchases
Conventional food purchases have declined from 64% to 39% since 2007
Sustainable food purchases increased from 36 percent in 2007 to 61 percent in 2010, and local (within 250 miles) food purchases increased from 27 percent to 52 percent in the same time period. Click to enlarge.

Goals & Progress

  1. Goal: Reduce the percentage of conventional foods purchased from 40 percent of total purchases to 35 percent, while prioritizing local foods. In order to define more sustainable food, Dining Services evaluates practices and existing certification programs, looking at criteria such as location, chemical usage and animal welfare.

    • Conventional food purchases decreased from 64 percent in 2007 to 39 percent in 2010. Conversely, sustainable food purchases increased from 36 percent in 2007* to 61 percent in 2010.
    • Local (within 250 miles) food purchases increased from 27 percent in 2007 to 52 percent in 2010 (see map in sidebar).
    • The student-run Princeton Garden Project created and is maintaining a new garden near the Frist Campus Center's South Patio to provide fresh herbs for the center's daily food offerings. This effort is a collaboration between Frist, Dining Services, Grounds and Building Maintenance, and the Office of Sustainability.

      *Working Groups coordinated by the Office of Sustainability and the Princeton Sustainability Committee set 2007 as the benchmark year while developing the Sustainability Plan.

  2. Goal: Reduce utility usage.

    Progress: Efficient new dishwashers have been installed in five of six dining halls, each saving about 300,000 gallons of water per year, or a total of 1.5 million gallons — more than enough to fill two Olympic-size swimming pools.

  3. Goal: Reduce and recycle food waste.

    • Dining Services has adopted a "tray-free" dining policy (providing larger plates and glasses and eliminating trays), endorsed by the Princeton Sustainability Committee, and has successfully implemented the program in five of six residential dining halls, as well as the Center for Jewish Life and the Graduate College. For all dining halls, tray-free dining has the potential to reduce water and energy costs by $4,000 per year, save up to 1.2 percent on food purchases, reduce food waste by up to 30 percent and avoid more than 23 metric tons of CO2 emissions.
    • Currently, Princeton sends all of its food waste (892 tons in 2009) to a local pig farmer.
    • Waste oil is collected and taken to a local plant to produce biodiesel. Between fall 2009 and spring 2010, 70 percent, or 1,901 gallons, of collected waste oil was recycled.

What's Next

Short Term

  • Transition to tray-free dining across all six dining halls and continue monitoring associated savings.
  • Develop a dining carbon-footprint application for use on mobile devices.

Long Term

  • Continue to refine criteria for defining foods as "sustainable."
  • Determine the feasibility of a "daylight dining" program in which dining halls turn off overhead lights and rely on ambient lighting. If all six dining halls used daylight dining eight hours a day, five days a week, they could avoid 12.6 metric tons of CO2 emissions.
  • Evaluate an alternative food waste recycling system (all food waste currently is processed off-site for pig feed), considering on-site and off-site options for composting and/or conversion.

"The (student) Greening Dining Committee has been working in close partnership with Dining Services since 2002 to create a more sustainable dining experience on the Princeton campus. Together, we've worked to develop Dining Services' sustainable practices and policies, including increasing organic and local food options, implementing tray-free dining and ensuring that all food waste goes to a local pig farmer. Looking ahead, we hope to examine more local purchasing options, increase vegetarian dining on campus and continue to promote campus awareness."
—Colleen McCullough '12, Greening Dining Chair

Trayless dining

A worker installed a new conveyer belt system in summer 2010 at the servery for the Rockefeller and Mathey college dining halls to accommodate tray-free dining. Dining Services will eliminate trays in all six undergraduate dining halls by next summer to save water, reduce food waste and avoid carbon dioxide emissions.


Local purchases map

More than half of the food purchased by Dining Services is from within a 250-mile radius. View a map of the local farms from which the University buys products.


"When we have the opportunity to walk a few hundred yards to select produce that is right in the ground, next door to our kitchen, it makes us embrace what we are doing, and it really invigorates us to put a little more passion into our food."
—Executive Chef Rob Harbison, Dining Services, Princeton University

Lesson Learned

External sustainability evaluators do not agree on a common definition for "local." In an effort to standardize an approach that complements the most rigorous external evaluator protocols, Princeton will be adopting a 250-mile radius as its definition of "local," a slightly less rigorous radius than its previous 200-mile limit.