Overview of Testing Protocol to Re-open Harvest Waters that were Closed in Response to the Deepwater Horizon Oil Spill
The U.S. Food and Drug Administration (FDA) oversees a mandatory safety program for all fish and fishery products under the provisions of the Federal Food, Drug, and Cosmetic Act, the Public Health Service Act, and related regulations. Adherence to these Acts and their supporting regulations helps ensure that the seafood U.S. consumers purchase is safe to eat. An important element in keeping seafood safe is making sure it is harvested from areas that do not present a chemical or biological hazard. The National Oceanic and Atmospheric Administration (NOAA) has the legislative authority to close and open federal waters for seafood harvesting while the states have authority to close and open waters under their jurisdiction.
In response to the oil spill, NOAA, FDA, the Environmental Protection Agency (EPA), and the Gulf States are implementing a comprehensive, coordinated, multi-agency program to ensure that seafood from the Gulf of Mexico is safe to eat. This is important not only for consumers who need to know their food is safe to eat, but also for fishermen who need to be able to sell their products with confidence.
The first step in protecting the public from potentially contaminated seafood is to close fishing and shellfish harvesting areas in the Gulf that have been or are likely to be exposed to oil from the spill. In addition, NOAA and FDA are monitoring fish caught just outside of closed areas, and testing them for petroleum compounds by sensory and chemical analysis and dispersants by sensory analysis, to ensure that the closed areas are sufficiently large so as to prevent the harvest of contaminated fish. Ultimately, the oil will begin to dissipate and a trusted, science-based method must be used to determine when it is safe to eat the seafood from areas that were exposed to the oil. Once it is determined that the seafood from a given area is safe to eat, the waters can be re-opened to harvesting. Below is a description of the risks oil poses and the protocol that will be followed in determining when it is appropriate to re-open harvest waters that were closed due to the oil spill.
How oil can make seafood unfit for consumption:
There are two ways that oil can cause seafood to be unfit for consumption. The first is through the presence of certain levels of chemicals known as polycyclic aromatic hydrocarbons (PAHs), some of which are carcinogenic. Oil is composed of many chemicals, but it is the carcinogenic PAHs which are of greatest concern because they can be harmful if consumed in sufficient amounts over a prolonged period of time. The second way seafood would be considered unfit for consumption is if it smells like petroleum product. This is known as the presence of “taint.” Under the law a product tainted with petroleum is considered “adulterated” and is not permitted to be sold as food. Petroleum “taint” in and of itself is not necessarily harmful and may be present even when PAHs are below harmful levels, however it should not be present at all.
How dispersants can make seafood unfit for consumption:
Based on current science, the dispersants used during the Deepwater Horizon response have a low potential to bioaccumulate in seafood and are low in human toxicity, therefore there is likely little public health risk associated with consuming seafood that has been exposed to them. Nonetheless, as a precaution, the U.S. government will continue to monitor the use of dispersants and test seafood that may have been exposed to them. It is possible for the dispersants to “taint” seafood with a chemical smell. Even though the dispersant “taint” may not be harmful, seafood possessing the chemical smell is considered adulterated and not permitted for sale.
Protocol for sampling, testing, and re-opening closed harvest waters:
- Re-opening fishing waters that were closed, but which were never actually exposed to oil. Harvest area closures include buffer zones around the contaminated areas as a precaution to account for any uncertainty about the exact location of the oil from day to day. There are also areas which federal and state officials closed in anticipation that oil would enter, but it never did enter. If it can be confirmed (e.g., through water quality sampling, aerial surveillance, and/or satellite imagery) that a harvest area was never exposed to the oil, that area may be re-opened without first testing seafood samples.
Re-opening harvest waters that were exposed to oil. The first criterion to be met before harvest waters exposed to oil are re-opened is that the water be free of oil from the spill. Once the oil has dissipated, re-opening of harvest waters may be performed on a species by species basis; that is, areas may be open to the harvesting of certain types of seafood, like finfish, but not others. For a closed area to re-open for harvesting of a given species, samples of the species taken from the waters must successfully pass both a sensory examination and chemical analysis in an approved laboratory. Testing will be performed on finfish, shrimp, crabs, and mollusks (e.g. oysters/mussels).
Criteria for sensory testing: A sample consists of the edible portion of the species of seafood being tested. A panel consisting of a minimum of 10 expert sensory assessors will evaluate each sample in both a raw and cooked state. In order for an area to be considered acceptable for re-opening from a sensory standpoint a minimum of seventy percent (70%) of the expert assessors must find NO detectable petroleum or dispersant odor or flavor from each sample. If any sample fails, the site from which it was collected remains closed.
Criteria for chemical testing: If all tested samples of a given species from a collection site pass the sensory criteria, additional samples will undergo chemical analysis to determine if harmful levels of PAHs are present. If harmful levels of PAHs are found in the samples, the site from which the sample was collected fails and remains closed. If the levels of PAHs in the seafood samples do not pose a health concern the site will be considered eligible for re-opening.
All contiguous sites must pass both sensory and chemical testing for an area to re-open.