Submitted to: Agriculture Handbook
Publication Type: Review Article
Publication Acceptance Date: July 20, 2002
Publication Date: N/A
Technical Abstract: Lemons (Citrus limon L. Burman f.) are grown year-round in California, which is the major producer. The primary quality characteristics are intensity and uniformity of yellow color, size, shape, smoothness, firmness, freedom from decay and defects including freezing damage, drying, mechanical damage, rind stains, red blotch, shriveling, and discoloration. The generally accepted standard is a minimum juice content of 28 to 30 percent. Lemons should be stored between 7 to 12 C depending on cultivar, maturity-ripeness stage at harvest, production area, and duration of storage and transport (can be up to 6 months). The optimal relative humidity is 85 to 95 percent. Because lemons are chilling sensitive, they must not be stored below 7 C. Adequate ventilation must be maintained during storage. Lemons should be stored away from produce with a strong odor. Controlled atmosphere conditions of 7.5 to 10 percent oxygen and up to 10 percent carbon dioxide can delay senescence, including loss of green color, but the risk of injury to the fruit is high and it is only rarely used. Levels of carbon dioxide CO2 sufficient to inhibit fungal growth, greater than 10 percent are not used because high carbon dioxide induces non-persistent but objectionable off-flavors. There are three main postharvest pathological diseases of lemon. Green Mold and Blue Mold are caused by Penicillium digitatum and P. italicum, respectively. Spores access the fruit rind through wounds. Sour Rot is caused by Geotrichum citri-aurantii which enters lemons through wounds made by insects, then infected fruit are digested by the pathogens and it spreads rapidly from fruit. Most quarantine concerns for lemons address eliminating fruit flies, such as the Carribean, Oriental, Mediterranean, and Mexican fruit flies.