scope:

This International Standard specifies a horizontal method for enumeration of microorganisms growing on the surface of a solid medium after aerobic incubation at 30 ºC. The method is applicable to: - products intended for human consumption or for animal feeding stuffs; - environmental samples in the area of food production and food handling. This part of the Standard is recommended for use: - if heat-sensitive organisms are likely to form a significant proportion of the total flora (eg: psychrotrophic organisms in chilled and frozen foods, dried foods, other foods that may contain heat-stressed organisms); - if obligately aerobic bacteria are likely to form a significant proportion of the total flora (eg: pseudomonas); - for products that contain small particles that may be difficult to distinguish from colonies in a pour plate; - for intensely coloured products whose colour would prevent the recognition of colonies in a pour plate; - if it is needed to distinguish between different types of colony as part of the quality assessment. This method also describes the use of a spiral plater, an accurate and rapid method of performing surface colony counts. The applicability of this International Standard to the examination of certain fermented food and animal feeding stuffs is limited and other media and/or incubation conditions might be more appropriate. However, this method may be applied to such products even though the predominant microorganisms in these products may not be detected effectively.