The word "quality" means many things. The definitions include: an essential or distinctive characteristic, property, or attribute; character with respect to fineness or grade of excellence; and high grade, superiority, excellence. All of these definitions can easily be applied to eggs, and consumers have different expectations of "quality" for eggs.
In general, egg quality can be broken out into three criteria: microbial, physical, and functional. Microbial quality relates to the presence of general microorganisms. These organisms could be indicators of general cleanliness, those that cause product spoilage, or foodborne pathogens. Eggs are a raw agricultural commodity and are perishable (i.e., they require refrigeration to reduce the likelihood of spoilage, decay, and growth of pathogenic organisms). Safe handling and cooking instructions are required for eggs according to 21 CFR 101.17(h).1 The primary pathogenic organism of concern for eggs and egg products is Salmonella spp., with particular emphasis placed on Salmonella Enteritidis.