Cell structures are very common in nature on molds, soil, air, water, and organic materials that resemble yeasts. Structurally, mold cells are arranged in succession and hyphae form branches of hyphae in different ways. The thickness of hyphae varies between 1 and 10 microns, depending on the type and environmental conditions. It is possible to see the filamentous structures called hyphae with the naked eye. Hyphae communities are generally defined as multicellular fungi, ie mold fungi.

Howard slide method, which is the most commonly used method in mold counting, is used to determine the microbiological quality of raw material used in the production of tomato products such as tomato paste, tomato juice, ketchup and some fruit products and to determine the effectiveness of hygiene practices in the enterprise. With the microscopic counting method Howard slide method, the hyphae communities in the field of view examined are evaluated as plus and minus and accordingly the moldy area rate is determined in the analyzed sample. The results are described as a percentage of moldy area. Microscope glasses which are specially designed for this study called Howard slide are used. A Howard slide has an 25 field of view.

The ratio obtained by the Howard slide method does not directly indicate the amount of mold in the product. The result of the positive 20 percent area shows that the product is not molded by 20 percent; However, this value shows how much moldy raw material is used in production.

Mold counting studies with Howard slide are performed in authorized laboratories within the scope of microbiological analyzes. During these studies, standards and test methods issued by domestic and foreign organizations are followed.