ISO 21527 Microbiology of Food and Animal Feed - Horizontal Method for Counting Yeast and Molds

ISO 21527 Microbiology of Food and Animal Feed - Horizontal Method for Counting Yeast and Molds

The ISO 21527 standard, developed by the International Standards Organization (ISO), consists of the following two parts under the main title "Microbiology of food and animal feed - Horizontal method for counting yeast and molds":

ISO 21527 Microbiology of Food and Animal Feed - Horizontal Method for Counting Yeast and Molds

  • ISO 21527-1 Part 1: Colony count technique for products with a water activity of more than 0,95
  • ISO 21527-2 Part 2: Colony count technique for products with a water activity of 0,95 or less

In the ISO 21527-1 standard, live yeast and molds in products with a water activity greater than 0,95 (eggs, meat, dairy products excluding milk powder, fruits, vegetables, fresh dough and similar) intended for human consumption or for feeding animals, at 25 degrees plus A horizontal test method for counting with the colony count technique at minus 1 degree is described. This test method does not allow the enumeration of mold spores. Neither the identification of fungal flora nor the examination of foods for mycotoxins are within the scope of this standard. The test method described in this standard is not considered suitable for enumeration of heat-resistant fungi such as byssochlamys fulva or byssochlamys nivea in canned or bottled fruit and vegetables.

For the purposes of this standard,

  • Yeast refers to a mesophilic aerobic microorganism, usually with a regular outline and a more or less convex surface, that forms opaque or shiny round colonies on the surface of the medium at 25 degrees Celsius using mycological agar medium under the conditions described in this standard. Yeasts develop round, lenticular, colonies in a medium rather than on it.
  • Molding refers to mesophilic aerobic filamentous microorganisms that, under the conditions described in this standard, often develop flat or fluffy spreading propagules/microbes on the surface of mycological agar media or colonies that often bear colored fruit or spore structures.
  • Propagul (microbe) refers to a living creature that can grow in a nutrient medium.
  • Colony refers to the localized apparent accumulation of microbial mass that develops from a living particle on or on a solid nutrient medium.

In the ISO 21527-2 standard, products (dried fruits, cakes, jams, dried meat, salted fish, cereals, cereals and cereal products, flours, hard products) with a water activity of less than or equal to 0,95 intended for human consumption or for feeding animals A horizontal test method is described for counting live yeasts and molds (nuts, spices and seasonings, etc.) at 25 degrees plus/minus 1 with the colony count technique.

This standard does not apply to dehydrated products with a water activity of less than or equal to 0,60 (dried grains, oil, spices, legumes, seeds, powders for instant drinks, dry products for pets, etc.) does not allow. Neither the identification of fungal flora nor the examination of foods for mycotoxins are within the scope of this standard. The test method described in this standard is for the detection of halophilic xerophilic fungi found in dried fish. Not suitable for counting.

For the purposes of this standard, osmophilic yeast (xerophilic mold) refers to fungus that can grow at a water activity of less than or equal to 0,95.

If there are international standards or national standards that are not compatible with this horizontal method for certain product groups, when such standards are reviewed, they are modified to comply with the ISO 21527 standard. Thus, in the end, the only remaining deviations from this horizontal method are those necessary for well-known technical reasons.

Among the numerous test, measurement, analysis and evaluation studies that our organization provides for businesses in various sectors, with its trained and expert staff and advanced technological equipment, testing services in accordance with the horizontal method for microbiology of food and animal feeds, yeast and molds counting within the scope of ISO 21527 standard. also gives.

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