NWPB finalizes watermelon cutting, shelf life study

To better understand the cutting, yield and shelf-life of watermelon, the National Watermelon Promotion Board (NWPB) conducted a cutting, yield, and shelf-life study in 2015. The board worked with the Food Innovation Center, a part of Oregon State University, to conduct the research. The study was designed to report on cutting methods for watermelon in foodservice and retail, provide shelf-life information for cut fruit, and collect information about how watermelon is used.

First, six chefs and retail food handlers were selected. The six included representatives from Moberi, Paley’s Place, Oregon Convention Center, Oregon Health & Science University, Sheridan Fruit Company, and Whole Foods. Those representatives were then observed cutting watermelon. They also took part in an interview about using watermelon. All but one organization used watermelon year-round. Primary usage included fresh cut, salads, garnish, protein accompaniment, fruit plate or bowl, and beverage applications. Some are also using the rind for pickles. If not, it was composted.

Between the six organizations, they used four cutting methods. The cutting methods were evaluated in the lab based on time to cut and yield. Once the best method was defined, there were 50 watermelons from three key sizes analyzed: 36, 45, and 60. The cutting method below was found to be the fastest, with little difference in yield from the others. This is the cutting method to receive the yield as stated below:

1. Cut off the ends, providing a base and access to the peel and rind

2. Angle the knife, place it where the white rind meets the red flesh and following the curve of the fruit, cut the rind off

3. Cut the whole watermelon into disks, width ways in the desired size of cubes

4. Lay the disks face down, pushing the smaller disks to one side and cut same size strips in both directions

Yield
Size	60	45	36
Time (min)	2.5	2.58	3.05
Flesh (lbs)	8.61	9.54	10.67
Skin (lbs)	3.61	4.24	7.17
Flesh (%)	70.50%	69.20%	59.80%

Once cut, the fruit was tested for shelf-life, up until day seven. The 36-count watermelon was still edible at day 7 and had a 7-day shelf life. The 45- and 60-count watermelon sampling and microbial study showed that the watermelon was still edible at day 4 and had a 4-day shelf life. Food Innovation Center researchers suggested further shelf-life research due to the 36-count being received refrigerated and the 45- and 60-count received at ambient temperatures, which could explain the shelf-life discrepancy. The NWPB has funded continuing research for 2016. Researchers stressed the need for education about washing the outside of the watermelon before cutting the fruit, NWPB said.

For more information on selection and storing, in addition to the research above, visit watermelon.org/foodservice.