Coliform bacteria are facultative anaerobes, gram-negative, non-spore microorganisms that produce gas from lactose 48 within hours. As we have seen, they form a very complex group. There are many bacteria in the enterobacteriaceae family that fall under this definition. However, in terms of food microbiology, escherichia coli, enterobacter aerogenes and enterobacter cloacae are the leading coliform bacteria. These bacteria species are the most sought-after bacteria in food microbiology laboratories. Species known as fecal coliforms in these bacteria are strictly not allowed in foodstuffs. Escherichia coli is the leading faecal coliform.

In the field of food microbiology, the most probable number (EMS) method is generally used when counting the total coliform group of bacteria. Because the number of bacteria that are allowed to be found in foods is too low to be detected by standard culture methods using solid medium.

Coliform (EMS) studies are carried out in authorized laboratories within the scope of microbiological analyzes. During these studies, standards and test methods issued by domestic and foreign organizations are followed. A few standards to consider are:

• TS ISO 4831 Microbiology of food and animal feed - Horizontal method for detection and counting of coliforms - Most probable number technique
• TS ISO 4832 Microbiology of food and animal feed - Horizontal method for counting coliforms - Colony counting technique
• TS EN ISO 9308-1 Water quality - Detection and enumeration of Escherichia coli and coliform bacteria - Part 1: Membrane filtration method for low bacterial soil flora waters
• Water quality - Detection and enumeration of Escherichia coli and coliform bacteria - Part 9308: The most probable number method
• Water quality - Detection and enumeration of Escherichia coli and coliform bacteria in surface and waste water - Part 9308: Inoculation in liquid media (Most Likely Number)