An alternative spelling of prokaryotes, the typically unicellular organisms including bacteria and cyanobacteria that lack a defined nucleus. In food microbiology the term covers the great majority of organisms of concern: spoilage bacteria, pathogens such as Salmonella and Listeria, and beneficial fermentation cultures alike. Their simple cellular organization, rapid growth, and metabolic versatility explain both their usefulness in fermented foods and the speed with which they can spoil perishables or cause illness. Distinguishing prokaryotes from eukaryotes such as yeasts and molds helps analysts choose appropriate detection, identification, and control methods.