Strategies to Avoid FDA Detention:

Antibiotic Residue Testing for Seafood

Reviewed and Approved by Steven Rogers, Chemistry Manager, Certified Laboratories 

1-Minute Summary 

  • The U.S. FDA monitors Chloramphenicol, Nitrofurans, and Malachite Green/Gentian Violet (MG/GV) in seafood.
  • Permissible levels: Chloramphenicol (0.15 ppb), Nitrofurans (0.5 ppb), MG/GV (0.5 ppb). 
  • Liquid Chromatography-Mass Spectrometry (LC-MS/MS) is the most common test method for the antibiotic residues. 
  • Alignment with your suppliers along with precise recordkeeping can prove vital for compliance. 
  • Select labs with ISO 17025 accreditation, experience, and advanced instruments. 



The international seafood market is under increasing scrutiny concerning antibiotic residue. In fact, the U.S. FDA began using artificial intelligence to screen for shrimp imports contaminated with antibiotics 

In this environment, importers must be proactive in ensuring their seafood products meet all standards to avoid FDA detention and costly delays when importing products into the U.S.   

In this blog, we'll take a closer look at the regulations and methods for antibiotic residue testing in seafood. This info will help you ensure speedy, compliant imports.  

New call-to-action

Understanding the FDA's Stance on Antibiotic Residue in Seafood 

The FDA is vigilant about monitoring antibiotic residue in seafood to support public health, notably… 

  • Chloramphenicol 
  • Nitrofurans 
  • Malachite Green and Gentian Violet (MG/GV) 

Before diving into the specifics of permissible levels, let's take a closer look at each one. 


A broad-spectrum antibiotic, chloramphenicol was initially a go-to solution for a variety of bacterial infections in both humans and animals. However, its use in food-producing animals has been discouraged due to concerns about aplastic anemia, a rare but severe blood disorder in humans.  

While it has been largely phased out in veterinary use in several countries, traces can sometimes be found in food products, leading to stringent monitoring. 


A group of antibiotics, nitrofurans were frequently used in aquaculture and livestock for their effective treatment against a wide array of bacterial infections. Their residues, particularly in seafood, became a concern due to potential carcinogenic effects. As a result, many countries, including the U.S., have banned their use in food animals. 

MG/GV (Malachite Green and Gentian Violet) 

Originally used as a dye, malachite green found its way into aquaculture due to its effective antifungal properties. Its metabolite, Leucomalachite Green, persists in fish tissue for an extended period.  

Gentian Violet is also known as “Crystal Violet”, so you will sometimes see the test named MG/CV. The four analytes measured by this analysis are Malachite Green, Leucomalachite Green, Gentian (Crystal) Violet, and Leucocrystal Violet. 

Table: Permissible Antibiotic Residue Levels in Seafood Imports 


Permissible Level (ppb) 








These standards, updated in 2022, arise from rigorous research linking high levels of these antibiotic residues to potential health risks.  

When businesses ensure their seafood products align with these standards, they're not just adhering to regulations, they're fortifying the trust consumers place in them and contributing to the larger goal of public wellbeing. 

What Can Seafood Importers do to Ensure Fast, Compliant Imports? 

Every importer wants their products to enter U.S. commerce safely and as quickly as possible. That said, antibiotic residue testing is one of the most effective tools in your arsenal for achieving these goals. The effectiveness and accuracy of these tests largely hinge on the methodologies and instruments used. 

  • Liquid Chromatography-Mass Spectrometry (LC-MS/MS) is the most common test method for the antibiotic residues noted above due to its unique ability to detect specific proteins or compounds.  
  • While the Enzyme-Linked Immunosorbent Assay (ELISA) method can be done, FDA does not generally accept it as a confirmatory test. 

If your seafood import is detained, you'll need to have a lab perform testing so the shipment can be released. Be sure to understand the FDA's draft guidance for collecting samples for release testing of fish and fishery products so you can ensure the fastest resolution possible. 

Quality Control and Supplier Monitoring 

Alignment with suppliers regarding FDA standards is critical. With regular laboratory testing for antibiotic residue in seafood, you can gain insights into the practices of your suppliers, ensuring consistent product quality that aligns with regulatory guidelines and meets customer demands.  

 Array of shrimp, salmon, and fish filets in retail store.  

Conduct antibiotic residue testing on your imports to help get your seafood into the U.S. quickly and without delays.  

Documentation and Traceability 

Another key practice to help speed your seafood imports is precise recordkeeping of test results. This serves as a backbone for audit readiness and recall processes. Opting to work with a laboratory that emphasizes detailed and transparent reporting can significantly bolster traceability and compliance efforts. 

Challenges in Antibiotic Residue Testing and How if Affects Seafood Importers 

Antibiotic residue testing for seafood carries complex challenges that can affect your ability to import your products into the country safely and as quickly as possible. Being aware of these challenges can help you choose the right laboratory testing partner, which we’ll talk about later. Here's a deep dive into the core challenges and how they affect you: 

  1. Sensitivity and Specificity:  

A test's sensitivity refers to its ability to detect even minuscule amounts of a substance. For example, with Chloramphenicol, levels as low as 0.15 parts per billion (ppb) must be detectable. Specificity, on the other hand, ensures that the test detects the correct substance, distinguishing it from other potential compounds. 

Importers' Concern:
If a lab lacks the expertise to maintain a balance between these two factors, false positives or overlooked residues can result. This could lead to potential FDA detention, resulting in logistical delays and financial losses. 

  1. Sample Complexity:

Seafood is a complex matrix of proteins, fats, salts, and other natural compounds. This diversity can obscure the detection of antibiotic residue, presenting what we term as "background noise" in the sample analysis. 

Importers' Concern:
Without a seasoned lab that can effectively separate the "noise" from the real data, you risk erroneous results. Inaccurate readings can lead to unwarranted inspections or even product recalls, affecting both timelines and brand reputation.     

  1. Time vs. Accuracy Dilemma:

The tug-of-war between rapid results and thorough, accurate testing poses challenges. Fast-track methods might provide results quicker but might skim over nuances. More detailed methods offer depth but can take longer. 

Importers' Concern:
Delays in receiving test results can postpone shipments and affect supply chain dynamics. However, prioritizing speed over accuracy can invite regulatory issues. Hence, choosing a test method should be based on the specific requirements of each batch of imports. 

What to Look for in a Seafood Testing Laboratory   

Working with a laboratory seasoned in seafood antibiotic testing is a strategic decision as important as choosing a customs broker or U.S. agent. Such a laboratory can offer optimized testing methods tailored to your needs.  

Here are 5 things to look for in your testing laboratory: 

  • Industry leading turnaround time to help get your products into commerce safely and as quickly as possible. 
  • Use of advanced instruments and validated methods for precision and accuracy. 
  • ISO 17025 accreditation to ensure quality and accountability.  
  • Experience with seafood testing in general and FDA imports in particular to help your import move as smoothly as possible. 
  • Regulatory expertise to ensure FDA compliance and help get your products released from FDA detention quickly. 

Why Choose Certified Laboratories for Antibiotic Residue Testing? 

  • Competitive seafood testing turnaround time.  
  • Our labs use LC/MS-MS, ELISA, and other advanced instruments and validated methods to provide the accuracy you need to keep your shipments moving. 
  • ISO 17025 accredited labs with robust quality-management systems.  
  • A rich history in seafood testing and FDA imports, providing insights help you navigate complex regulations with confidence. 

Antibiotic residue testing, particularly for chloramphenicol and nitrofurans, is more than a mere regulatory checkpoint – it’s a cornerstone of a trustworthy seafood business. By leveraging the capabilities of specialized laboratories, you can ensure you products sail smoothly into the U.S. market.  

Reach out to us with questions or to get a quote for your seafood antibiotic residue testing and we’ll be glad to help.  



Topics: Food Safety, Food & Beverage, Seafood