Public Advisory on Pesticide Residues on Vegetables

As part of its regulatory activity in protecting the public from potentially unsafe foods, the Division of Environmental Health of the Department of Public Health and Social Services (DPHSS) has been testing fruits and vegetables for residual pesticide.  The most recent batch tested by the U.S. Food and Drug Administration on behalf of this Department, which included three vegetables and two fruits, revealed the presence of residual pesticide that is not authorized for use on one of the vegetables.  The remaining four types of produce (two vegetables and two fruits) either did not have any residual pesticide present or the levels of residue were within acceptable ranges.

The vegetable found with the unauthorized pesticide was a sample of kang-kong (Ipomoea aquatic), a leafy green vegetable also known as Chinese water spinach or swamp cabbage.  It was contaminated with the pesticide chlorothalonil, which is not approved for use on this particular vegetable.

Chlorothalonil (2,4,5,6-tetrachloroisophthalonitrile) is a general use pesticide, particularly a fungicide, that is sold under the commercial brand names, such as Bravo Weather Stik, and Daconil, and also as tetrachloroisophthalonitrile.  Chlorothalonil has caused irritation of skin and mucous membranes of the eye and respiratory tract on contact.  Cases of allergic contact dermatitis have been reported.  When used and applied appropriately, pesticides pose a minimal risk to the general public.  Finding minute traces of pesticide or its components, called “residual pesticide,” on fruits and vegetables is not uncommon. 

Locally, pesticides are regulated by the Guam Environmental Protection Agency (GEPA), but residual pesticide on agricultural food products is the responsibility of DPHSS.  Under the law, any food with a pesticide level above the tolerance level established by the U.S. Environmental Protection Agency, or found to contain any level of unapproved pesticide, is deemed adulterated and cannot be sold.  There exists no U.S. Environmental Protection Agency approved pesticides for use on kang kong pursuant to their federal regulations; therefore, any presence of residual pesticide will be considered a violation regardless of the levels detected.

As a result of the finding, this Department is working closely with GEPA and the Department of Agriculture in its investigation.  Because two months have passed between the initial sampling of the kang kong and the receipt of the laboratory analysis, the contaminated kang kong is no longer present at retail facilities. 

This Department would like to remind the public to regularly wash hands after handling raw agricultural commodities that may be tainted with unnecessary levels of residual pesticide. 

DPHSS further recommends the following to the public:


  • Wash fruits and vegetables using large amounts of cold or warm tap water (with no soap or other detergents) before serving.  Washing will help remove pesticide residues, dirt, and microorganisms that may be on the surface of these foods.  Scrub with a brush when appropriate for produce with firm skin or hard rind.
  • Throw away outer leaves of leafy vegetables, such as lettuce and cabbage.
  • Peeling and discarding outer skin or rinds of some produce is an option since some pesticides are absorbed into the plant.
  • Always wash squash and melons since dirt or bacteria, and possibly residual pesticide, on the surface can be transferred to the inner flesh during cutting.
  • If cooking fruits and vegetables; do so thoroughly.  Cooking can break down some pesticide residues because they tend to be heat sensitive.
  • Eating a wide variety of fruits and vegetables can limit exposure to any one type of pesticide residue.

DPHSS wishes to emphasize that while ingestion of minute concentrations of pesticide can occur during consumption of commercially and homegrown fruits and vegetables, the benefits of eating these foods outweigh the potential risks, so the public is encouraged to follow the recommendations provided.  For further inquiry into this matter, the Division of Environmental Health of DPHSS may be contacted at 735-7221.  Dangkolo Na Si Yu’us Ma’ase!

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