2026-09-23 FDA Warning Letter: Neogen Corporation Cited for CGMP/Drugs for Animals/Prepared, Packed or Held Under Insanitary Conditions/Adulterated
Letter issued · posted to fda.gov .
Subject as published: CGMP/Drugs for Animals/Prepared, Packed or Held Under Insanitary Conditions/Adulterated
TL;DR
The short version: On September 23, 2026, the FDA's Center for Veterinary Medicine issued Warning Letter CMS# 731018 to Neogen Corporation (President and CEO Mike Nassif) regarding Neogen Vet® HYCOAT® (Hyaluronate Sodium Sterile Solution), citing violations of the Federal Food, Drug, and Cosmetic Act. The FDA's multistate investigation into over 95 cases—involving the largest number of horse deaths associated with a veterinary product quality defect—identified significant microbiological contamination (five fungal species including Purpureocillium lilacinum and Gongronella lacrispora) in lot 5A001, which was recalled January 28, 2026, and determined the product was manufactured under insanitary conditions (inadequate cleaning, no air pressure monitoring, no viable particulate sampling, poor facility repair) at the contract manufacturer's facility. The product is deemed adulterated under FD&C Act sections 501(a)(1), 501(a)(2)(A), and 501(c), and misbranded under sections 502(a) and 502(f)(1) for lacking adequate directions for use.
Argus analysis
# FDA Warning Letter Analysis: Neogen Corporation
**Company and Findings**
Neogen Corporation, based in Lansing, Michigan, received a Warning Letter from the FDA's Center for Veterinary Medicine on September 23, 2026, regarding its veterinary product Neogen Vet® HYCOAT® (Hyaluronate Sodium Sterile Solution). The FDA conducted a multistate investigation following over 95 serious adverse events in horses, including the largest number of deaths associated with a product quality defect in any FDA-regulated veterinary medical product on record. Testing confirmed that distributed lots contained viable fungal contaminants despite being labeled as sterile, and the manufacturing facility operated under insanitary conditions. Neogen initiated a recall of affected lots in January 2026.
**Regulatory Citations and Meaning**
The violations cite FD&C Act sections 501(a)(1), 501(a)(2)(A), 501(c), and 502(a)(1). Section 501(c) addresses purity and quality falling below representations; section 501(a)(1) covers filthy or decomposed substances; section 501(a)(2)(A) pertains to insanitary preparation conditions; and section 502(f)(1) addresses inadequate directions for use. The contamination included five fungal species (Purpureocillium lilacinum, Paraisaria heteropoda, Gongronella lacrispora, Purpureocillium sodanum, and Isaria takamizusanensis). Manufacturing deficiencies included absent sporicidal cleaning, no differential pressure monitoring, inadequate environmental controls, and a cleanroom facility in poor repair unsuitable for sterile production.
**Response Timeline and Industry Implications**
Neogen must respond within 15 working days with corrective actions and supporting documentation. Peer compliance officers should monitor for follow-up FDA communications, potential import alerts, and whether the agency pursues additional enforcement actions. The letter emphasizes distributor responsibility for contract manufacturer oversight—a critical message for companies outsourcing production. Expect heightened FDA scrutiny of animal sterile products and cleanroom operations across the veterinary pharmaceutical sector.
Severity context
High severity. Typically QSR / device CGMP, adulterated-drug, or significant labeling matters — usually drives a documented corrective and preventive action (CAPA) program.
Regulatory background
CGMP citations typically reference 21 CFR Part 211 (drugs) or 21 CFR Part 600 (biologics). Common subjects include identity testing of incoming components (211.84), validated cleaning procedures (211.67), and stability program design (211.166).
What peer compliance teams typically do next
Most compliance officers at peer companies use a Warning Letter against a named entity as a checklist for their own CAPA program. Common steps: pull the verbatim FDA letter; map each cited 21 CFR section against the team’s SOP library; confirm CAPA coverage; brief the QMR (Quality Management Review) on whether the cited subject matter is in scope for the next internal audit. The 15-business-day response window applies to the cited entity, not to peers — but a documented internal review against the cited subjects is what regulators expect to see if a peer is later inspected on the same topic.
Excerpt from the FDA Warning Letter (public domain, 17 USC §105)
WARNING LETTER Neogen Corporation MARCS-CMS 731018 — September 23, 2026 More Warning Letters Warning Letters About Warning and Close-Out Letters Delivery Method: Via Email Product: Animal & Veterinary Drugs Recipient: Recipient Name Mike Nassif Recipient Title President and CEO Neogen Corporation 740 E Shiawassee St Lansing , MI 48912 United States mnassif@neogen.com Issuing Office: Center for Veterinary Medicine United States September 23, 2026 WARNING LETTER CMS# 731018 Re: 731018 Dear Mr. Nassif: This Warning Letter summarizes significant violations of the Federal Food, Drug, and Cosmetic Act (FD&C Act) pertaining to Neogen Vet® HYCOAT® (Hyaluronate Sodium Sterile Solution; herein after referred to as HYCOAT®), which you distribute, and which was manufactured for you by the contract manufacturer (b)(4) . In response to a series of serious adverse events in horses, the United States Food and Drug Administration (FDA) conducted a multistate investigation. As described in more detail below, we collected samples of your product, inspected the manufacturing facility, and reviewed the epidemiological and clinical evidence associated with over 95 individual cases. Our investigation linked significant contamination of your purportedly sterile product, HYCOAT®, to this incident, which involved the largest number of deaths in horses to be associated with a product quality defect in any FDA-regulated medical product for veterinary use. This contamination also resulted in the most fatalities in any species ever associated with a sterile FDA-regulated medical product for veterinary use. On January 28, 2026, you recalled numerous lots of HYCOAT® (including HYCOAT® 2mL, lots 4L001 and 4L002, and HYCOAT® 10 mL, lot 5A001) due to the risk of microbial contamination. From (b)(4) , we inspected the contract manufacturer’s facility, located at (b)(4) , and found HYCOAT® was manufactured under insanitary conditions, rendering the product adulterated under FD&C Act section 501(a)(2)(A). During our investigation, we collected and analyzed samples and confirmed that HYCOAT® lot 5A001 (which purports to be sterile) was, in fact, not sterile, and is therefore adulterated under FD&C Act sections 501(a)(1) and 501(c) and misbranded under section 502(a). We subsequently reviewed HYCOAT®’s labeling and determined that the product is also misbranded under section 502(f)(1) of the FD&C Act because its labeling fails to bear adequate directions for use. For the above reasons, the introduction of adulterated and misbranded HYCOAT® into interstate commerce violates section 301(a) of the FD&C Act, 21 U.S.C. 331(a). You can find the FD&C Act and FDA regulations through links on FDA's homepage at www.fda.gov. Microbiological Contamination in a Purportedly Sterile Product Under section 501 of the FD&C Act, "A drug or device shall be deemed to be adulterated…if… its strength differs from, or its purity or quality falls below, that which it purports or is represented to possess." FD&…
Excerpt only. The full verbatim Warning Letter is the source of truth — always read the original before regulatory decisions.
The verbatim FDA Warning Letter is the source of truth. Always read the original before acting on any analysis or summary on this page.
Read the full letter on fda.gov ↗Frequently asked questions
- What does a "high" severity rating mean for this letter?
- High severity. Typically QSR / device CGMP, adulterated-drug, or significant labeling matters — usually drives a documented corrective and preventive action (CAPA) program.
- What is the regulatory background for a CGMP — Current Good Manufacturing Practice warning letter?
- CGMP citations typically reference 21 CFR Part 211 (drugs) or 21 CFR Part 600 (biologics). Common subjects include identity testing of incoming components (211.84), validated cleaning procedures (211.67), and stability program design (211.166).
- What is the standard FDA response window for a warning letter?
- FDA warning letters typically require a written response within 15 working days of receipt, outlining the corrective and preventive actions the company will take.
- Has Neogen Corporation had FDA enforcement actions before?
- This is the only FDA Warning Letter Argus HQ has on file for Neogen Corporation as of 2026-09-29. Argus ingests new FDA enforcement records daily.
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methodology
The analysis above is produced by Anthropic Claude Haiku 4.5 against the verbatim FDA Warning Letter excerpt and is brand-voice lint-checked before publish. The TL;DR is the same summary that ships in the customer email digest. Severity is auto-classified by Argus from the subject string and letter body using rules documented in lib/ingestion/fda-warning-letters.ts.
Argus HQ is informational only. Summaries and analyses are AI-generated and may contain errors, misclassifications, or omissions. Verify against the FDA source URL above. Argus HQ is not a law firm, accounting firm, or regulatory agency, and provides no legal, accounting, financial, medical, or regulatory advice.
Compiled by Argus HQ Research from FDA primary sources · Reviewed by Andy Gaber, Founder
Cite this record
Reusing this data in reporting or research? Here’s a ready-made citation.
Argus HQ Research (2026). 2026-09-23 FDA Warning Letter: Neogen Corporation Cited for CGMP/Drugs for Animals/Prepared, Packed or Held Under Insanitary Conditions/Adulterated. Digital Empire Holdings LLC. Retrieved from https://argushq.ai/fda/warning-letter/fda-wl-neogen-corporation-2026-09-23-cgmp
"2026-09-23 FDA Warning Letter: Neogen Corporation Cited for CGMP/Drugs for Animals/Prepared, Packed or Held Under Insanitary Conditions/Adulterated." Argus HQ Research, Digital Empire Holdings LLC, 2026, argushq.ai/fda/warning-letter/fda-wl-neogen-corporation-2026-09-23-cgmp.
Argus HQ Research. "2026-09-23 FDA Warning Letter: Neogen Corporation Cited for CGMP/Drugs for Animals/Prepared, Packed or Held Under Insanitary Conditions/Adulterated." Digital Empire Holdings LLC. Accessed October 3, 2026. https://argushq.ai/fda/warning-letter/fda-wl-neogen-corporation-2026-09-23-cgmp.
@misc{argushq_argushq_ai_fda_warning_letter_fda_wl_neogen_corporation_2026_09_23_cgmp_2026,
title = {2026-09-23 FDA Warning Letter: Neogen Corporation Cited for CGMP/Drugs for Animals/Prepared, Packed or Held Under Insanitary Conditions/Adulterated},
author = {{Argus HQ Research}},
year = {2026},
publisher = {Digital Empire Holdings LLC},
url = {https://argushq.ai/fda/warning-letter/fda-wl-neogen-corporation-2026-09-23-cgmp},
note = {Accessed: October 3, 2026}
}