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A microgreen is a tiny vegetable green that is used both as a visual and flavor component or ingredient primarily in fine dining restaurants. Fine dining chefs use microgreens to enhance the beauty, taste and freshness of their dishes with their delicate textures and distinctive flavors.
Microgreen or micro green refers to a whole plant harvested at a young seedling stage after a few leaves have begun to develop beyond the cotyledons. It is distinguished from sprouts, which are younger and processed in water in dark conditions: i.e., still germinating where just the cotyledons have opened up, or have not opened with roots still attached (like bean sprouts), or sprouted grains, etc.
Microgreens are a tiny form of young edible greens produced from various kinds of vegetables, herbs or other plants. They range in size from 1” to 1½” including the stem and leaves. A microgreen has a single central stem which has been cut just above the soil line during harvesting. It has two fully developed cotyledon leaves and usually one pair very small, partially developed true leaves. The typical stem and leaf configuration for micro greens is at about 1 to 1.5 in (25 to 38 mm) in height, and 0.5 to 1 in (13 to 25 mm) in width across the top and includes the stem, cotyledon leaves and one set of very small, partially developed true leaves. The average crop-time for most microgreens is 7–10 days from seeding to harvest. Despite their small size, microgreens can have very strong flavors, though not as much so as full-sized greens.
Beginning in Southern California, microgreens have been grown in the United States since about the mid‑1990s. There were initially very few varieties offered. Those available were such as Arugula, Basil, Beets, Kale, Cilantro and a mixture called Rainbow Mix. Having spread eastward from California, they are now being grown in most areas of the country with an increasing number of varieties being produced.
Microgeens have recently become more popular due to a commonly held belief that they possess an especially high nutritional content. The first ever nutritional study of microgreens was done in the summer of 2012 by the Department of Nutrition and Food Science, University of Maryland , indicating promising potential that microgreens may indeed have particularly high nutritional value compared to mature vegetables. The study has certain flaws such as comparing some wrong items and not performing the actual nutritional analysis on the mature comparisons. There are numerous online articles[which?] describing how to grow them. Many small "backyard" growers have sprung up selling their greens at farmers' markets or to restaurants. Most of these smaller growers may lack adequate food safety programs or insurance. Several coalitions of small organic farms fought successfully to be exempted from the recently passed food safety legislation.
Microgreens have three basic parts; a central stem, two cotyledon leaves, and typically the first pair of very young true leaves. Microgreens vary in size depending upon the specific variety grown with the typical size being 1 to 1.5 in (25 to 38 mm) in total length. When the green grows beyond this size, it should no longer be considered a microgreen. Larger sizes have been called Petite Greens.
It is important to understand that Microgreens are not the same as sprouts. There are several important differences. Understanding the different production methods of each can help clear up any confusion between them.
Sprouts are germinated or partially germinated seeds. A sprout consists of the seed, root, stem and pale, underdeveloped leaves. The FDA seeks to regulate all businesses that produce sprouts due to numerous outbreaks of food poisoning ("sproutbreaks"). Salmonella and Escherichia coli O157:H7 have been the major causes of sprout-associated illness outbreaks. Commercial sprout processors are asked to follow rigorous FDA Guidelines for production that include multiple laboratory tests of each batch for the presence of pathogenic bacteria, to minimize the threat of food borne illness. Despite these precautions, there continues to be regular recalls and alerts relating to sprouts with more and more restaurants removing them from menus to reduce their liability. In 2011, 52 people died and thousands became ill due to consumption of locally grown organic sprouts in Europe. The two largest U.S. retailers Walmart and Kroger are no longer selling sprouts. "Sprouts present a unique challenge because pathogens may reside inside the seeds where they cannot be reached by the currently available processing interventions," Payton Pruett, Kroger's Vice President of Food Safety, said in an October 19, 2012 news release.
Sprout seed is not actually planted, instead, sprouts are produced (processed) in water. A high density of seed is placed inside of sprouting equipment or enclosed containers. The seed germinates rapidly due to the high moisture and humidity levels maintained in the enclosures. Seeds can also be sprouted in cloth bags that are repeatedly soaked in water. The sprouting process occurs in dark or very low light conditions. These dark, wet, crowded conditions are ideal for the rapid proliferation of dangerous pathogenic bacteria.
After a few days of soaking and repeated rinsing in water (several times a day to minimize spoilage), the processing is complete and the sprouts are ready to consume. These sprouted seeds become a tangle of pale roots, stems and leaf buds. Microgreens cannot be grown in this manner.
Microgreens are grown in soil or soil-like materials such as peat moss. Microgreens require high light levels, preferably natural sunlight with low humidity and good air circulation. Microgreens are planted with very low seed density compared to sprout processing. Crop times are generally one to two weeks for most varieties, though some can take four to six weeks. Microgreens are ready to harvest when the leaves are fully expanded. Harvesting is usually with scissors cutting just above the soil surface, excluding any roots. Some growers sell them while still growing, rooted in the growing trays so that they can be cut later. Once removed from their growing environment, these trays of microgreens must be used quickly or they will rapidly begin to elongate and lose color, and flavor.
The conditions that are ideal for properly grown microgreens do not encourage the growth of dangerous pathogens. These growing methods would not work for the production of sprouts.
With stronger flavors compared to sprouts, they are an excellent ingredient with a wide selection of leaf shapes, textures and colors.
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.