As of September 30, 2019, the FDA has tested 339 domestic samples and 473 import samples of frozen berries.

Of the frozen berries sampled, the FDA found genetic material from hepatitis A virus in five samples and genetic material from norovirus in eight samples, using multiple-laboratory validated RT-qPCR methods for the detection of hepatitis A virus and norovirus viral sequences in soft fruit. These 13 samples were then further tested by another method called Sanger sequencing to see if the viral material could be further characterized by examining a separate, distinct section of the viral genomes. Nine of the 13 samples could be further characterized using this technique. When the FDA detected genetic material from hepatitis A virus or norovirus in a sample, the agency notified the firm of the finding(s) and worked with them to take appropriate action to protect the public health.