What’s on Your Fish?Sodium Tripolyphosphate: Another Chemical to Avoid

Health RisksSodium tripolyphosphate, or STPP, is a suspected neuro-toxin according to the National Institute for Occupational Safety and Health’s (NIOSH) Registry of Toxic Effects of Chemical Substances.1 Food-grade STPP may cause acute skin irritation, and prolonged contact with skin should be avoided.2 STPP is listed on the U.S. Environmental Protec-tion Agency’s Federal Insecticide, Fungicide and Rodenti-cide Act as a registered pesticide,3 and it is also registered as an air contaminant under California’s Occupational and Safety Health Act.4 Although the FDA considers STPP to be “generally recognized as safe” as a food preservative,5 its household and industrial uses — such as in cleaning and sanitizing agents — suggest that exposure can be danger-ous in the short-term, particularly if it is inhaled.

Based on these warnings from federal agencies, it is likely that consumers may be adversely affected when preparing and cooking STPP-soaked seafood. Exposure may occur on the skin during handling and preparation, from vapors during the cooking process (especially if steam is gener-ated), or even from inhaling the vapors while you eat.

If It’s Bad for Our Health, Why Is It Being Used?In seafood manufacturing, sodium tripolyphosphate (STPP) is often used to prevent excessive “thaw drip” — the liquid that is released from frozen fillets of fish as they thaw — and to improve the external appearance of a product by adding a glossy sheen.6 STPP treatment can also be used

You want to know what’s in your food, and this is especially true when it comes to fresh seafood. Unfortunately, the fish fillet you see in the store may have

been treated with a chemical called sodium tripolyphosphate. This much-debated additive can make expired products appear firmer and glossier, and could dupe you into buying old or spoiled fish that could make you sick. Worse yet, exposure to the chemical itself could also be harmful for your health.

Fact Sheet • June 2010

FISH

as a binding agent to hold flaky fish products together, such as whiting fillets or blocks of minced fish.7 This treatment is done for cosmetic purposes, and proponents claim that treatment does not affect the quality of the fish. However, STPP treatment cannot improve the underly-ing quality of the fish and does not help to preserve the fish. Because STPP changes how the product looks, it can make spoiled fish appear fresh, increasing the risk of ill-ness for consumers.

There is also concern that the use of STPP can result in consumer fraud, because it increases the weight of the product due to water retention and heavier fish can be sold for more money. Use of STPP specifically to add weight is not allowed by international standards, but the intentional or accidental overuse of STPP will lead to a product that has increased water weight, causing consum-ers to pay a higher price for fish sold per pound.

Application of STPP to seafood takes between seconds and minutes, depending on the salinity of the product, 8 and can affect the flavor and quality of the seafood, typi-cally resulting in a soapy or alkaline taste.9 This tends to occur with lighter or more delicately flavored seafood, like scallops.

Regulation of Sodium TripolyphosphateMany countries have taken a precautionary approach to the use of STPP in food products, but the United States does not have a limit of how much STPP can be present in seafood products. The European Union, Canada and Brazil all have limits on the total level of STPP allowed in seafood products, generally between 0.1% and 0.5% of the final product.10 The U.S. regulations, by comparison, list STPP as “Generally Recognized as Safe” when used in accor-dance with “Good Manufacturing Practice,” but this can leave consumers vulnerable.11

How Can I Avoid This Additive in my Seafood?Check labels: Unfortunately, labeling isn’t required for fresh seafood treated with STPP, although some packaged seafood products may list it as an ingredient.

Choose scallops and shrimp labeled as “dry”: Scallops and shrimp are two of the most commonly found sea-food items treated with STPP, and those labeled as “dry” have not been treated with STTP. Avoid seafood marked as “wet,” which means that they have been soaked in an STPP solution.

Ask at markets or restaurants: Whenever you’re purchas-ing seafood, whether at the market or in a restaurant, ask if the seafood has been treated with sodium tripolyphos-phate, or STPP.

Endnotes

1 Scorecard: The Pollution Information Site. “Sodium Tripolyphos-phate (CAS Number: 7758-29-4).” Available at http://scorecard.org/chemical-profiles/summary.tcl?edf_substance_id=7758-29-4#hazards , accessed May 25, 2010.

2 Innophos. “[Material Safety Data Sheet] Sodium Tripolyphosphate, Food Grade.” March 2007; and National Institute for Occupational Health and Safety. “International Chemical Safety Cards: Sodium Tripolyphosphate.” August 2002. Available at http://www.cdc.gov/niosh/ipcsneng/neng1469.html

3 Scorecard: The Pollution Information Site. “Registered Pesticides (Federal Insecticide, Fungicide and Rodenticide Act).” Page undated. Available at http://scorecard.org/chemical-groups/one-list.tcl?short_list_name=pest , accessed May 25, 2010.

4 Scorecard: The Pollution Information Site. “Air Contaminants (California Occupational and Safety Health Act).” Page undated. Available at http://scorecard.org/chemical-groups/one-list.tcl?short_list_name=caac , accessed May 25, 2010.

5 Food and Drug Administration. “Guidance for Industry: 1991 Letter to Seafood Manufacturers,” February 2009. http://www.fda.gov/Food/GuidanceComplianceRegulatoryInformation/GuidanceDocu-ments/Seafood/ucm123018.htm

6 Aitken, A (2001). “Polyphosphates in Fish Processing.” Food and Agricultural Organization (in partnership with the Support Unit for International Fisheries and Aquatic Research, SIFAR.) FAO Corporate Document Repository. http://www.fao.org/wairdocs/tan/x5909e/x5909e01.htm

7 Ibid.8 Lampila, L.E. and J.P. Godber (2001). “Food Phosphates.” In Alfred

Larry Branen , P Michael Davidson, Seppo Salminen, et al. (Eds.), Food Science. London: M. Dekker, 867.

9 Ibid., 868.10 Goncalves, Alex Augusto and Jose Luis Duarte Ribeiro (2008). “Do

Phosphates Improve the Seafood Quality? Reality and Legislation.” Pan-American Journal of Aquatic Sciences (2008) 3(3): 242-244.

11 Ibid., 242.

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