Fuji apples retain flavor and crispness for up to nine months after harvest now that the apple industry has adopted ARS research findings on storing the fruits. Previously, this flavorful apple variety was available to consumers only during the fall harvest. No one knew how to keep it fresh for a lengthy market period. But, over six growing seasons, ARS scientists determined how to adapt controlled atmosphere (CA) conditions to maximize its benefits on Fuji apples. CA is a common industry technique used to extend storage life for other varieties of apples by modifying the concentration of the main gasses naturally present in air--oxygen, nitrogen, and carbon dioxide. Scientists analyzed the Fuji for changes in color, firmness, starch, sugar and acid content. Results: the best CA treatment for Fuji apples holds storage temperature at 34 degrees F. and maintains oxygen at one to 1.5 percent and carbon dioxide at one percent or less (Fujis are sensitive to this gas). Fuji apple production is rapidly expanding in Washington state. In 1992, Washington produced about 805,000 boxes of Fujis. By 1995, production had jumped to nearly 3.5 million boxes. This growing season, Washington production will jump to an estimated 7.1 million boxes. California, second in production, will yield an estimated 2.3 million boxes.
Tree Fruit Research Laboratory, Wenatchee, WA
James P. Mattheis, (509) 664-2280

Ginning mills that remove cotton fibers from cotton seed do not threaten an area's air quality. That's the word from an ARS study of exhaust from gins in 11 states. The study found only very low emission levels of eight potentially hazardous materials such as arsenic, lead and mercury. None of the materials was present at levels exceeding federal clean air regulations, and only very low levels of agricultural chemicals were found. The ARS engineers concluded the only emission of concern was particles of cotton leaves, stems and fibers, as well as some soil particles with diameters of 10 microns or less. Cotton gins are generally a minor source of these particles compared to most other industries. The engineers are now modifying the most popular emission control device, known as a cyclone, so the ginning industry could meet more stringent air quality standards if enacted.
Southwestern Cotton Ginning Research Laboratory, Mesilla Park, NM
Ed Hughs, (505) 526-6381

Human noses are superior to expensive electronic instruments when it comes to sniffing apples for freshness. Researchers are seeking better strategies for storing apples so consumers get tastier fruit. They want to pinpoint the best blend of oxygen and carbon dioxide for controlled-atmosphere storage, a standard industry technique. Electronic instruments measure volatiles, or aromas, given off by the stored apples to determine how well the apples are faring. But human noses can detect some key fruit aromas better than electronic ones. Cooperators at Oregon State University in Corvallis trained 10 testers to rate apple aromas--just as wine connoisseurs rate fine wines--using terms like "fruity" and "musty." So far, they've noted that fruit and floral aromas in Gala apples lose their pizzazz after 11 weeks in storage. The researchers' next step: finding the best gas levels so fruit stays both firm and aromatically appealing.
Tree Fruit Research Laboratory, Wenatchee, WA
James P. Mattheis, (509) 664-2280, mattheis@ftrl.ars.usda.gov

Scientists have devised a new lab test that quickly identifies whether a natural yeast strain has the potential to control aflatoxin on tree nuts. Aflatoxin, produced by Aspergillus fungi, is a known carcinogen. The fungus can infect tree nuts such as almonds, walnuts and pistachios along with peanuts, corn and cottonseed. To safeguard food and feed safety, government agencies monitor and limit aflatoxin levels. Last year, ARS scientists first discovered that some yeasts can reduce Aspergillus populations and toxin production on nuts. But finding the most effective yeasts among hundreds of natural strains has required costly, time-consuming chemical analyses. With their new test, the scientists need only see what happens after they put into a lab dish both a candidate yeast and a special Aspergillus strain. This strain, developed by other researchers in the 1980's, has a genetic mutation. It forms a red-orange pigment as a nontoxic precursor to making aflatoxin. If a candidate yeast blocks aflatoxin synthesis, the fungi won't make this pigment. Instead, only the white color of spreading yeast appears. That tells researchers the yeast is worth a closer look. This summer they hope to conduct greenhouse tests of the most effective strains--yeasts in the Pichia genus.
Western Regional Research Center, Albany, CA
Sui-Sheng Hua, (510) 559-5905, ssth@pw.usda.gov

Last Updated: July 14, 1997
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