Division I.4.1 Freezing in exceptional cases

Where practical difficulties arise, which make it impossible to process the samples within 48 hours after the collection of the fish tissues, it may be acceptable to freeze the tissue specimens in transport medium at – 20 °C or below and to carry out virological examination within 14 days. However, the fish tissue shall only be frozen and thawed once before examination. Records shall be kept with details on the reason for each freezing of fish tissue samples.