As of January 1, 2019, the Food and Drug Administration (FDA) has tested 747 fresh herb samples (441 domestic, 306 import), and 526 processed avocado or guacamole samples (435 domestic, 91 import).
Of the fresh herb samples, nine tested positive for Salmonella (4 domestic, 5 import), and six tested positive for Shiga-toxin producing E. coli (STEC), with further characterization determining that the STEC were incapable of causing severe illness. The FDA did not detect E. coli O157:H7 in any of the fresh herb samples that it tested. Of the processed avocado or guacamole samples, 11 tested positive for Listeria monocytogenes (9 domestic, 2 import), and two tested positive for Salmonella (both domestic samples).
The FDA also began testing its fresh herb samples for Cyclospora cayetanensis in July 2018, given that Cyclospora-related illnesses typically occur during the summer. The agency detected Cyclospora cayetanensis in two of the 141 samples of domestically grown fresh herbs tested, and in four of the 74 samples of imported fresh herbs tested. Testing for all pathogens is still underway and no conclusions can be drawn at this time.