Environmental Engineering Reference
In-Depth Information
2.5 1,4-DIOXANE IN FOOD
The i rst systematic study designed to determine the levels of 1,4-dioxane in food was conducted in
2003 by a team of Japanese scientists led by Tetsuji Nishimura of Japan Food Research Laboratories
in Tokyo (Nishimura et al., 2004). A number of risk assessments and drinking water fact sheets have
cited earlier literature to assert that 1,4-dioxane is commonly found in fried chicken, tomatoes,
shrimp, and other foods. However, none of the studies cited actually quantii ed the amount of
1,4-dioxane present, and the studies were all performed in the 1970s and 1980s, before analytical
methodologies for 1,4-dioxane detection were improved (ATSDR, 2004). Table 2.13 summarizes
early citations of 1,4-dioxane in various food products at unquantii ed levels.
In Nishimura's landmark study, a market basket approach was taken to analyze groups of food
by blending them together to assay 1,4-dioxane content. Food was prepared in the same manner in
which consumers cook food for routine consumption, using purii ed water and clean utensils. Raw
and cooked foods in 12 dietary groups were blended together with other foods from the same group
and then analyzed by using active carbon solid-phase extraction cartridges (described further in
Chapter 4), coupled with GC and mass spectrometry. 1,4-Dioxane was found in all foods except rice
and rice noodles; detections were in the low part per billion range. Corresponding dietary intake
was determined to be in the nanogram-per-day range, far below the applicable risk thresholds. The
study does not specii cally explain the cause of the nearly ubiquitous presence of 1,4-dioxane in
food; however, the widespread presence of 1,4-dioxane from industrial discharges to river water and
groundwater used for irrigation and food processing are suggested as possible reasons. Table 2.14
summarizes the i ndings from the analysis of 1,4-dioxane in different food groups.
Food additives have been regulated in the United States and Europe for their 1,4-dioxane content.
The U.S. Food Chemicals Codex restricts residual 1,4-dioxane content in polysorbates to 10 mg/kg.
Polysorbate 60 [polyoxyethylene (20) sorbitan monostearate] is an emulsii er used in ice cream,
frozen custard, ice milk, fruit sherbet, and other frozen desserts. Polysorbate 60 is used alone or in
combination with polysorbate 65 and/or polysorbate 80. Polysorbates have been found to contain
trace levels of 1,4-dioxane and ethylene oxide as impurities, which result from the production pro-
cesses used for polysorbates (FDA, 1999). Polysorbate 60 and polysorbate 80, which are produced
from the polymerization of polyoxyethylene, have historically been found to contain 1,4-dioxane
(Birkel et al., 1979). Levels of 1,4-dioxane in these compounds have been reported to range from 5
to 6 ppm (mg/L) (ATSDR, 2004).
1,4-Dioxane was detected in Tween 20 and Tween 80 (polysorbate 20 and polysorbate 60) at
approximately 100 and 200 ppm, respectively (Guo and Brodowsky, 2000). Table 2.15 summarizes the
varieties of polyoxyethylene-based emulsii ers in which 1,4-dioxane may be present in trace amounts.
Eating ice cream and other frozen desserts that use polysorbates as an emulsii er could cause a
maximum exposure to 1,4-dioxane of 19 ng per person per day (FDA, 1999). For a 70 kg person,
TABLE 2.13
Studies Reporting the Identifi cation of 1,4-Dioxane in Food Products at Unquantifi ed
Levels Prior to Japanese Study by Nishimura et al. (2004)
Food Product
Reference
Chicken l avor and meat volatiles
Shahidi et al. (1986)
Fried chicken volatile l avor compounds
Tang et al. (1983)
Tomato fruit juice volatiles
Chung et al. (1983)
Fat oil compound (tillnoloin) formed in deep frying
Chang et al. (1978)
Cooked shrimp volatile l avor compounds
Choi et al. (1983)
Patis (Philippine fermented i sh sauce)
Sanceda et al. (1984)
Brazilian coffee
Spadone et al. (1990)
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