A frequently performed microbiological count. It is the number of bacteria growing on a non-specific solid bacteriological growth medium under the specified conditions. A sample of product is blended in an appropriate solution and aliquots of the suspension, after dilution as necessary, are applied to the medium. The inoculated plate is incubated in air and, after a specified time, the number of visible colonies are counted. The results are typically expressed as colony forming units (c. F. U. )/g. An important variable in the experimental procedure is the temperature of incubation. An incubation temperature around 35ºC favours mesophiles, and provides a general index of sanitary or hygienic conditions of the handling and processing of the product. Lower temperatures, around 20ºC, favour psychrophiles and are more indicative of spoilage bacteria on chilled fish.