Seafood handling, processing, and packaging workers may be exposed to airborne particles, including bits of seafood, additives, soot, and salt water mist. Industrial hygienists can measure the types and amount of particulate matter these workers may breathe to assess their exposure, and if needed, recommend controls to prevent adverse health effects related to the inhaled particles.
To collect samples of airborne particles in the air during processing tasks, the seafood worker wears a small pump on their waist, which is connected by tubing to a sampling device attached to their shoulder/collar area near their “breathing zone.”* Particles are collected according to their size, as particle size determines where they tend to deposit in the respiratory tract. Larger particles get stuck in the nose and upper airways, whereas smaller particles can reach the lungs, including the gas exchange region.
Typical monitoring for particulate matter separates and measures the “inhalable” (diameters < 100 µm) and “respirable” size fractions (<10 µm), which can be useful in assessing compliance with regulatory and advisory health standards. However, this approach has a limited ability to determine potential exposures to specific allergen particles, which comprise only a tiny fraction of the total particulate matter collected. These particles have been previously identified as a concern for the shellfish industry because some contain a protein, which has been known to cause an allergic or asthmatic response in sensitive people. The major allergen in bony fish (fish with skeletons made of bone) is parvalbumin which is found primarily in the muscle tissue of the fish. Analysis of this seafood protein in air samples was limited primarily to research facilities, but recent advances allow for commercial analysis that employs ELISA antibodies, which are extracted with a buffered saline solution from particles collected on 1.0 µm Teflon filters. Our evaluations in the bony fish processing industry indicate that the parvalbumin protein is a small component of the total particulate matter in the air, it must be specifically measured to determine its presence. It is important to note that the amounts of allergens measured are extremely tiny, often measured in nanograms (billionths of a gram), such that parvalbumin may make up less than 0.1% of the inhalable particulate concentration.
Currently, there are no established regulatory or health-based exposure limits for exposure to parvalbuminagainst which to compare sample results. However, air sampling results can be used to identify areas or tasks that have measurable parvalbumin levels, compare them to background values within the industry, and to define jobs with higher concentrations of exposure in order to focus control efforts. To date, air samples taken during fish (e.g. salmon, cod, herring) processing tasks presented in the scientific literature indicate allergen concentrations ranging from 2 to 75,000 ng/m3. Higher concentrations have been associated with the use of older processing equipment, the presence of hot processes and/or steam, and the use of pressurized water for cleaning.
Research is ongoing to determine the impact of other airborne components that may be responsible for adverse health effects including endotoxin, protease enzymes (e.g. Trypsin), histamine, other allergenic proteins, and even non-seafood related biological agents such as Anisakis simplex, a nematode that can be present in seawater.
*The breathing zone is the area near the workers nose and mouth where air is drawn into the lungs.
Stephanie Carter, MSPH, PhD, CIH, is an industrial hygienist with professional experience in the petrochemical industry, aluminum smelting industry, fisheries industry, and as an educator. Her experience includes special training in chemical exposure assessment, confined space ventilation, and welding health and safety.
WASHINGTON + SOUTH CAROLINA + FLORIDA + TEXAS