New bacteria are always confronted in the production, storage, storage and transportation processes of the enterprises. From the cleaning of the production sites to the materials used in the packaging of the products, various bacteria create problems in many areas.

Enterobacteriaceae family of bacteria is the most common type of bacteria affecting the food sector. Bacteria in this group are detected and counted by routine tests and analyzes performed in laboratories. In this context, the count of enterobacteriaceae bacteria is an increasingly important study showing the quality of food.

In fact, there is no internationally determined limit for these studies, which are accepted as food hygiene standards. Nevertheless, in line with the demands of the enterprises, these analyzes are generally made according to the bulk or spreading culture count method. The only medium used in these counts is Violet Red Bile Dextrose (VRBD) Agar. The difference of these nutrients from the standard applied VRB Agar is that glucose is used in its composition, not lactose. Therefore, in the presence of bacteria, a dark red color area develops on this medium. Bacteria not from the Enterobacteriaceae family form a colorless colony.

During the analysis, the general method of casting or smearing cultural counting and double layer method is applied. In the food industry there are other developed systems for total enterobacteriaceae counting, especially on surfaces, but the most preferred method is VRBD Agar.

Enterobacteriaceae bacteria counting studies are carried out in advanced laboratories within the scope of microbiological analyzes. The standards used during these analyzes are as follows:

• TS ISO 21528-1 Microbiology of food and animal feed - Horizontal method for the detection and enumeration of enterobacteriaceae - Part 1: Search and enumeration with the most probable number technique with pre-enrichment
• TS ISO 21528-2 Microbiology of food and animal feeds - Horizontal method for detection and counting of Enterobacteriaceae - Part 2: Colony counting method