How to Store Lemons and Prevent Disease: A Detailed Guide to Practical Methods

Lemon, also known as ningguo, foreign lemon, yimu fruit, etc. Because its taste is extremely sour, pregnant women with liver deficiency like to eat it most, so it is called yimu fruit or yimu zi. Lemon is rich in citric acid, so it is known as a “citric acid warehouse”. Because the taste is especially sour, it can only be used as a top-grade seasoning, used to prepare beverages, dishes, cosmetics and medicines. Lemon is an evergreen small tree of the Rutaceae family, native to Malaysia. At present, it is distributed in the Mediterranean coast, Southeast Asia and the Americas, and is also cultivated in Taiwan, China, Fujian, Guangdong, Guangxi and other places in China. Lemon has a unique rich aroma and sour taste. The juice contains 5%-7% citric acid and is rich in vitamin C. It has a fragrant smell and has the effects of calming, promoting qi, appetizing, helping digestion and increasing appetite. The fruit can be used to make acid juice and spices. Fresh fruit can be used to prepare beverages. It has high value in the international market and occupies a certain economic position. In our country, it is mostly cultivated in Sichuan. The quality is relatively good, and it is cultivated in Guangdong, Guangxi, Fujian, Taiwan, and Zhejiang. 

(1) Storage characteristics and varieties Lemon fruit is firm, bright in color, with a green stem, plump oil cells, and a fragrant smell. The lemon peel tissue is tight and the waxy layer is thick, making it one of the more storage-tolerant citrus fruits. Lemon has the habit of flowering and fruiting in all four seasons, and its fresh fruit supply period is long. Lemons are generally picked in October or January, packed in standard wooden boxes with biphenyl wrapping paper. When picking lemons, use scissors to cut them, leaving no fruit stalk, and handle them gently during harvesting and placement. 

There are many varieties of lemon, but only about ten are cultivated in our country, and the market generally does not distinguish varieties. Main cultivated varieties: Eureka and Lisbon are more storage-tolerant; citron, Vella Franca, and Jiannao have poor storage tolerance. 

(2) Suitable storage conditions A temperature of 10°C and a relative humidity of 85%-90% are the best storage conditions for lemons. Under these conditions, lemons can be stored for 8-9 months with no obvious decline in quality. Some varieties are suitable for storage at 12-15°C. 5%-10% oxygen can significantly extend the storage life of lemons. Carbon dioxide inhibits the degreening of lemons, and long-term storage in high carbon dioxide deepens the color of mature fruit and reduces the citric acid content. 

(3) Storage methods and management 

① Cold storage Store the harvested lemons in wooden boxes and transport them to a cold storage room, pre-cool to 10°C, and select lemons free of pests, diseases, mechanical damage, and rot for storage. Make small packaging bags from 0.01 mm thick high-density polyethylene film or 0.02 mm thick low-density polyethylene film, pack the lemons individually, twist the bag openings tightly, and place them in packaging boxes. Stack the packaging boxes into piles in the storage room. Leave gaps between the piles to facilitate ventilation. At a storage temperature of 10°C and a relative humidity of 85%-90%, lemons can be stored for 8-9 months. 

② Ventilated storage room storage After transporting the harvested lemons to a ventilated storage room, remove insect-damaged, diseased, injured, and rotten fruit, wrap each fruit in 0.01 mm thick high-density polyethylene film, and place them in packaging boxes. Stack the packaging boxes in the storage room in a “pin” shape. Leave gaps between the piles and maintain the storage room temperature at 10-15°C and relative humidity at 85%-90%. During storage, pay attention to the management of storage temperature. In the early and late periods, when the outside temperature is relatively high, strengthen ventilation. Open the ventilation holes every night to let cool air enter the storage room, and close the ventilation holes in the early morning to help lower the temperature. In the severe cold season in the middle period, pay attention to cold protection and heat preservation, and strive to keep the ventilated storage room temperature at 10-15°C. 

(4) Precautions and disease prevention measures Lemon rot is mainly spoilage caused by fungi, with no physiological rot. Lemon blue mold and green mold mostly occur after 3 months of storage; lemon stem-end rot occurs at the end of storage. Fungicides can be used to treat lemon fruit before storage.