Microbiology of the food chain — Detection and enumeration of Cryptosporidium and Giardia in fresh leafy green vegetables and berry fruits

ISO 18744:2016 specifies a method that is applicable for the detection and enumeration of Cryptosporidium oocysts and Giardia cysts on or in food products that are described herein as fresh leafy green vegetables and berry fruits. With suitable controls, it may also be applicable for the examination of other fresh produce.

The microscopy descriptions are for Cryptosporidium spp. oocysts and Giardia duodenalis cysts of size ranges which include those species (Cryptosporidium) or assemblages (Giardia) known to be pathogenic to humans.

This method does not include any molecular analysis and therefore is not suitable for the determination of the species or genotypes/assemblages of Cryptosporidium oocysts and Giardia cysts. The method will detect all species and genotypes/assemblages that are known to be pathogenic for humans and also others that are not. For further identification, molecular typing assays are required. However, these cannot be reliably performed if process positive controls have been spiked into the samples, as the result of molecular typing assays will be obfuscated.

This method does not allow the determination of viability or infectivity of any Cryptosporidium ooc