Fourier Transform Infrared Spectroscopy and Chemometrics for the Rapid Screening of Economically Motivated Adulteration of Honey Spiked With Corn or Rice Syrup.

Due to its high price, increased consumption, and limited production, honey has been a main target for economically motivated adulteration (EMA). An approach combining Fourier-Transform infrared spectroscopy (FTIR) and chemometrics was evaluated to develop a rapid screening tool to detect potential EMA of honey with either rice or corn syrup. A single-class soft independent modeling of class analogy (SIMCA) model was developed using a diverse set of commercial honey products and an authentic set of honey samples collected at four different U.S. Department of Agriculture (USDA) honey sample collection locations. The SIMCA model was externally validated with a set of calibration-independent authentic honey, typical commercial honey control samples, and those spiked with rice and corn syrups in the 1-16% concentration range. The authentic honey and typical commercial honey test samples were correctly predicted with an 88.3% classification rate. High accuracy was found in predicting the rice and corn syrup spiked samples above the 7% concentration range, yielding 97.6% and 94.8% correct classification rates, respectively. This study demonstrated the potential for a rapid and accurate infrared and chemometrics method that can be used to rapidly screen for either rice or corn adulterants in honey in less than 5 min.

Analysis of Per- and Poly(fluoroalkyl) Substances (PFASs) in Highly Consumed Seafood Products from U.S. Markets.

Seafood consumption has been identified as one of the major contributors of per- and poly(fluoroalkyl) substances (PFASs) to the human diet. To assess dietary exposure, highly consumed seafood products in the United States were selected for analysis. The analytical method previously used for processed food was extended to include four additional long-chain perflurocarboxylic acids (PFCAs), which have been reported in seafood samples. This method was single-lab-validated, and method detection limits were reported at 345 ng kg-1 for perfluorobutanoic acid (PFBA) and 207 ng kg-1 for perfluoropentanoic acid (PFPeA) and below 100 ng kg-1 for the rest of the PFAS analytes. The 81 seafood samples (clams, crab, tuna, shrimp, tilapia, cod, salmon, pollock) were analyzed for 20 PFASs using the updated analytical method. Most of the seafood packaging was also analyzed by Fourier transform infrared-attenuated total reflectance (FTIR-ATR) to identify packaging potentially coated with PFASs. None of the packaging samples in this study were identified as having PFASs. A wide range of concentrations was observed among the seafood samples, ranging from below the method detection limit to the highest concentration of 23 µg kg-1 for the sum of PFASs in one of the canned clam samples. Such a wide range is consistent with those reported in previous studies. The highest concentrations were reported in clams and crabs, followed by cod, tuna, pollock, tilapia, salmon, and shrimp. Technical perfluorooctanoic acid (PFOA) dominated the profile of the clam samples, which has been consistently found in other clam samples, especially in Asia. Long-chain PFCAs, specifically perfluoroundecanoic (PFUdA) and perfluorododecanoic (PFDoA), were the most frequently detected analytes across all seafood samples. The trends observed are comparable with those in the literature where benthic organisms tend to have the highest PFAS concentrations, followed by lean fish, fatty fish, and aquaculture. The results from this study will be used to prioritize future studies and to inform steps to reduce consumer exposure to PFASs.

Effect of high pressure processing on migration characteristics of polypropylene used in food contact materials.

The migration of small molecular mass organic compounds from polypropylene (PP) copolymer films into food simulants during and after high pressure processing (HPP) was studied. An overlapping temperature profile was developed to isolate the pressure effect of HPP (700 MPa, 71°C, 5 min) from equivalent thermal processing (TP) at atmospheric pressure (0.1 MPa). Chloroform, toluene, methyl salicylate, and phenylcyclohexane were chosen as surrogate compounds, and were spiked into test polymer films at concentrations of 762-1152 mg kg-1 by a solvent soaking technique. Migration (w/w) of surrogate compounds from loaded PP films into Miglyol 812 (a medium-chain triglyceride mixture) and 10% ethanol was quantified by headspace GC/MS during HPP and TP, and subsequent storage at 25°C for up to 10 days. HPP significantly delayed migration of the surrogates from PP into both food simulants relative to TP. The average migrations into Miglyol after TP and HPP were 92.2-109% and 16-60.6%, respectively. Diffusion coefficients estimated by migration modelling showed a reduction of more than two orders of magnitude for all surrogate compounds under high pressure at 700 MPa (AP' = 8.0) relative to equivalent TP at 0.1 MPa (AP' = 13.1). The relative Tg increase of PP copolymer under compression at 700 MPa was estimated as Tg+94°C. For 10% ethanol, average migrations after TP and HPP were 9.3-50.9% and 8.6-22.8%, respectively. During extended storage, migration into both simulants from HPP-treated samples was initially slower than that from untreated or TP-treated films. However, after 8-24 hours of storage, the differences in percent migration of selected surrogates were not significant (p > .05) among the treated PP films. Therefore, the physical changes of PP films that occur during HPP appear to be reversible with a return to their original dimensions and diffusion properties after decompression.

Single-laboratory validation of a method for the determination of select volatile organic compounds in foods by using vacuum distillation with gas chromatography/mass spectrometry.

Recent studies showed that headspace and purge and trap methods have limitations when used to determine volatile organic compounds (VOCs) in foods, including matrix effects and artifact formation from precursors present in the sample matrix or from thermal decomposition. U.S. Environmental Protection Agency Method 8261A liberates VOCs from the sample matrix by using vacuum distillation at room temperature. The method was modified and validated for the determination of furan, chloroform, benzene, trichloroethene, toluene, and sytrene in infant formula, canned tuna (in water), peanut butter, and an orange beverage (orange-flavored noncarbonated beverage). The validation studies showed that the LOQ values ranged from 0.05 ng/g toluene in infant formula to 5.10 ng/g toluene in peanut butter. Fortified recoveries were determined at the first, second, and third standard additions, and concentrations ranged from 0.07 to 6.9 ng/g. When quantified by the method of standard additions, the recoveries ranged from 56 to 218% at the first standard addition and 89 to 117% at the third. The validated method was used to conduct a survey of the targeted VOCs in 18 foods. The amounts found ranged from none detected to 73.8 ng/g furan in sweet potato baby food.

Determination of siloxanes in silicone products and potential migration to milk, formula and liquid simulants.

A pressurised solvent extraction procedure coupled with a gas chromatography-mass spectrometry-selective ion monitoring (GC-MS-SIM) method was developed to determine three cyclic siloxanes, octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5), dodecamethylcyclohexasiloxane (D6) and three linear siloxanes, octamethyltrisiloxane (L3), decamethyltetrasiloxane (L4), dodecamethylpentasiloxane (L5), in silicone products. Additionally, two different extraction methods were developed to measure these siloxanes migrating into milk, infant formula and liquid simulants (50 and 95% ethanol in water). The limits of quantification (LOQs) of the six siloxanes ranged from 6 ng/g (L3) to 15 ng/g (D6). Silicone nipples and silicone bakewares were extracted using pressurised solvent extraction (PSE) and analysed using the GC-MS-SIM method. No linear siloxanes were detected in the silicone nipple samples analysed. The three cyclic siloxanes (D4, D5 and D6) were detected in all silicone nipple samples with concentrations ranging from 0.5 to 269 µg/g. In the bakeware samples, except for L3, the other five siloxanes were detected with concentrations ranging from 0.2 µg/g (L4) to 7030 µg/g (D6). To investigate the potential migration of the six siloxanes from silicone nipples to milk and infant formula, a liquid extraction and dispersive clean-up procedure was developed for the two matrices. The procedure used a mix of hexane and ethyl acetate (1 : 1, v/v) as extraction solvent and C18 powder as the dispersive clean-up sorbent. For the liquid simulants, extraction of the siloxanes was achieved using hexane without any salting out or clean-up procedures. The recoveries of the six siloxanes from the milk, infant formula and simulants fortified at 50, 100, 200, 500 and 1000 µg/l ranged from 70 to 120% with a relative standard derivation (RSD) of less than 15% (n = 4). Migration tests were performed by exposing milk, infant formula and the liquid simulants to silicone baking sheets with known concentrations of the six siloxanes at 40°C. No siloxanes were detected in milk or infant formula after 6 h of direct contact with the silicone baking sheet plaques, indicating insignificant migration of the siloxanes to milk or infant formula. Migration tests in the two simulants lasted up to 72 h and the three cyclic siloxanes were detected in 50% ethanol after an 8-h exposure and after 2 h in 95% ethanol. The highest detected concentrations of D4, D5 and D6 were 42, 36 and 155 ng/ml, respectively, indicating very limited migration of D4, D5 or D6 into the two simulants.

Determination of bisphenol A in U.S. infant formulas: updated methods and concentrations.

An updated survey of U.S. infant formula was conducted to determine the concentrations of bisphenol A (BPA). The purpose was to accurately assess BPA concentrations across the infant formula market, accounting for lot variability, and determine if geographic location or can age influences BPA concentrations. A method was developed to measure BPA in formula utilizing isotope dilution, solid-phase extraction, and liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The method was tested and found to be reproducible (10% relative standard deviation), reliable (47 +/- 1% recovery), and sensitive (0.15 ng g(-1) method detection limit). Over 160 analyses were conducted using 104 formula containers representing 36 products. Samples from U.S. east and west coast markets demonstrated no significant difference, and concentrations in older cans were not higher. BPA concentrations in liquid formula (0.48-11 ng g(-1)) were consistent with previous studies, and BPA was detected in only 1 of 14 powder formula products analyzed.