However, the potential for food safety issues with microgreens may be increasing due to the number of indoor microgreen growing operations in which excessive seed density, low light intensity, low air circulation, or most commonly, a lack of GAP (good agricultural practices) and GMP (good manufacturing practices) based food safety procedures. Certain provisions of the Guidance for Industry: Reducing Microbial Food Safety Hazards For Sprouted Seeds may be beneficial and prudent for growers of microgreens to follow. Also, not all plants can be grown as microgreens due to toxicity concerns. For instance, nightshade plants (eggplants, tomatoes, potatoes, peppers, etc.) should not be grown as microgreen sprouts, since nightshade sprouts are toxic. Storage and commercial transport Microgreens have a long shelf life if stored and packaged properly. Optimal methods of storing and transporting microgreens are currently being studied. Commercial microgreens are most often stored in plastic clamshell containers, which do not provide the right balance of oxygen and carbon dioxide for live greens to breathe. This is why microgreens are normally sold cut and packaged in a non breathable container. When freshly cut the shelf life for microgreens can be several weeks. Some growers add a food safe moisture wicking material in the bottom of the container to extend shelf life. Moisture control and temperature are the two most important factors when considering the longevity of packaged microgreens and their transport. "After harvesting, microgreens should be kept as cool as possible without damaging the product. Minimizing the time the product is left at room temperature should be a required practice. Microgreens should be stored in a clean, refrigerated area at 4°C or less to minimize microbial growth. A thermometer should be installed and monitored regularly in the temperature-controlled environment. Microgreens should also be stored in a manner that prevents product damage. Stacking too many clamshell packages or bags of product on top of each other could cause damage to the product at the bottom of the stacks, which raises the risk of faster deterioration of the final product. While shelf life will vary from species to species and variety to variety, most microgreens will have a shelf life of approximately 5 to 10 days with proper handling and storage. The high level of care, attention and proper storage put into the product needs to be transferred into the distribution stages. Microgreens need to be transported in refrigerated spaces to reduce risk