At this point, CDC is saying that that outbreak appears over. While FDA identified Thompson International as the source, FDA had not been able to identify any definitive reason for the contamination.
"FDA has completed over 2000 product and environmental analyses from multiple Thomson International Inc. locations and surrounding areas, including water, soil, and scat samples. Although a variety of genetic strains of Salmonella Newport have been detected, as well as multiple other Salmonella serotypes, a genetic match to the outbreak strain has yet to be identified in any of the samples collected. Additional sample analysis is underway. Although the outbreak is being declared over, the FDA will continue its root cause investigation and will communicate any findings that could assist future prevention efforts. "
FDA Outbreak Investigation
https://www.fda.gov/food/outbreaks-foodborne-illness/outbreak-investigation-salmonella-newport-red-onions-july-2020
Outbreak Investigation of Salmonella Newport: Red Onions (July 2020)
CDC announces the end of the outbreak; FDA continues its investigation.
Case Counts
Total Illnesses: 1,127
Hospitalizations: 167
Deaths: 0
Last illness Onset Date: September 11, 2020
States with Cases: AK (25), AL (2), AZ (39), AR (2), CA (128), CO (32), CT (2), DE (2), FL (8), GA (11), HI (3), ID (43), IL (54), IN (4), IA (31), KS (3), KY (3), ME (6), MD (7), MA (2), MI (47), MN (19), MS (5), MO (11), MT (72), NE (10), NV (11), NH (1), NJ (12), NM (3), NY (14), NC (6), ND (9), OH (11), OK (1), OR (109), PA (27), RI (3), SC (1), SD (23), TN (7), TX (2), UT (115), VA (10), WA (150), WV (3), WI (11), WY (27)
Total Illnesses: 1,127
Hospitalizations: 167
Deaths: 0
Last illness Onset Date: September 11, 2020
States with Cases: AK (25), AL (2), AZ (39), AR (2), CA (128), CO (32), CT (2), DE (2), FL (8), GA (11), HI (3), ID (43), IL (54), IN (4), IA (31), KS (3), KY (3), ME (6), MD (7), MA (2), MI (47), MN (19), MS (5), MO (11), MT (72), NE (10), NV (11), NH (1), NJ (12), NM (3), NY (14), NC (6), ND (9), OH (11), OK (1), OR (109), PA (27), RI (3), SC (1), SD (23), TN (7), TX (2), UT (115), VA (10), WA (150), WV (3), WI (11), WY (27)