The objective of this study was to document the effects of phytic acid, tannic acid, and zinc on iron uptake in an in vitro digestion/Caco-2 cell culture model. The effects of phytic acid and tannic acid on iron uptake were measured at increasing molar ratios of FeCl3 to phytic acid or tannic acid. Maximal inhibition of iron uptake by phytic acid occurred at a 1:10 ratio of Fe to phytic acid. Dialyzable Fe decreased with a low Fe to phytic acid ratio but increased with Fe:phytic acid ratios greater than 1:3 indicating that more iron was soluble at higher phytic acid levels but less available. As in human studies, heme iron was less inhibited by phytic acid than nonheme iron. Tannic acid was a more potent inhibitor of nonheme iron uptake, as maximal inhibition (97.5%) of iron uptake occurred at a ratio of 1:1 or less. The addition of ZnCl2 to the digest at ratios of 1:0.5 and 1:1 decreased iron uptake by 57 and 80%, respectively. Overall, the results agree qualitatively with studies in humans and demonstrate the relative effects of these compounds on iron uptake in this model system. This study provides key information for determining iron availability under more complex meal conditions.

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This study describes a new method developed for detection of 10 different perfluorochemicals (PFCs) in cow's milk, seven perfluorinated carboxylates and three perfluorinated sulfonate salts. After attempting multiple methods employing both acidic and basic extractions, a basic extraction using 10 mM sodium hydroxide in methanol digestion along with weak anion-exchange solid-phase extraction was employed. Vortex mixing and varying sonication times were compared as part of sample processing. Results show that sonication during sample processing yield decreased recovery of longer chain perfluorinated carboxylates. The final method developed was used to determine the concentration of PFCs in 12 raw and 49 retail milk samples from across the United States. With the exception of a single raw milk sample obtained from a dairy farm that had applied PFC containing biosolids to its fields, there were no milk samples containing PFCs.

This paper reports the validation and application of a method for determination of 10 perfluorochemicals (PFCs) in retail fish and shellfish. The analytes of interest were 7 perfluorinated carboxylates and 3 perfluorinated sulfonates. Fish and shellfish samples were digested with a basic solution of 10 mM sodium hydroxide in methanol before sonication and solid phase extraction through weak anion exchange. Analysis was performed using liquid chromatography-tandem mass spectrometry. Recoveries from spiking five different types of fish and shellfish indicate that the method performs similarly with different fish types, and recoveries were over 90% for all analytes. Forty-six retail samples, collected between 2010 and 2012, including 13 different types of fish and shellfish were analyzed for PFCs. The 13 different types included the top 10 most-consumed fish and shellfish in the United States according to data collected by the National Fisheries Institute. Two Standard Reference Materials were also analyzed. Most fish and shellfish had no detected PFCs; only 11 samples of the 46 tested had detectable concentrations of PFCs.