Spoilage of lemons can occur through several means: 1. Mold growth such as blue mold or green mold is a major cause of spoilage, entering through injuries on the lemon peel. 2. Bacteria such as Lactobacillus and Leuconostoc can also lead to spoilage, producing undesirable flavors. 3. Environmental factors like temperature, moisture, and gas composition influence spoilage rates, with optimal storage conditions being 10-14°C, 90% humidity, and controlled atmosphere. 4. Proper handling including cleaning of storage areas and removal of damaged or moldy fruit can help prevent contamination and extend shelf life.