Controlled Atmosphere Packaging Keeps Cut Honeydew Melon Fresh Longer

Cut-up honeydew melons stay fresh and marketable longer, thanks to new controlled atmosphere procedures worked out by scientists with the Agricultural Research Service.

The researchers' goal: simulate the modified atmosphere packaging that supermarket chains use to extend fresh produce's shelf life. The result: Cut-up honeydew stayed fresh 2 days, or 20 percent, longer with reduced microbial growth. Honeydew cubes prepared at the supermarket typically have a sale date of only 2 or 3 days after they're cut.

Alley E. Watada, food technologist at ARS' Horticultural Crops Quality Laboratory in Beltsville, MD, subjected cut-up honeydews to a controlled atmosphere of 2 percent oxygen and 10 percent carbon dioxide at 41 degrees F for 9 days. His control sample was stored in air.

On day 5, melon cubes from the controlled atmosphere had less bacterial growth and a stronger honeydew aroma than those held in air. Day 6 showed the controlled-atmosphere samples still moist with good green color, aroma, taste and sweetness, most of which lasted through day 9. Honeydew cubes stored in air had microbial growth and an offensive odor on day 9.

Similar benefits can be reaped by supermarkets using modified atmosphere packaging if the proper gas mixture is maintained. This mixture will change if the holding temperature in the supermarket rises. As temperature increases, so does the respiration rate; but the rate of oxygen (air) transmission into the package cannot keep pace with the increased oxygen usage. Eventually, the oxygen is depleted. This anaerobic condition harms the honeydew melon and increases the chance of harmful bacteria growing in the package. Thus, packaged cut-up honeydew melons must be kept at 41 degrees F at all times.

Scientific contact: Alley E. Watada, Horticultural Crops Quality Laboratory, Beltsville, MD 20705-2350; phone (301) 504-6128, fax (301) 504-5107, e-mail awatada@asrr.arsusda.gov.