Jung 2017 — Inorganic arsenic in Korean infant rice powders and rice snacks

Summary

Jung (Woosuk University, Republic of Korea) measured inorganic arsenic in 59 rice-based infant foods marketed in South Korea — 28 ready-to-cook infant rice powders and 31 puffed-type infant rice snacks — using a previously validated gas chromatography–tandem mass spectrometry method with one-step British Anti-Lewisite derivatization. The author reports this as the first measurement of iAs in ready-to-cook Korean infant rice powders and Korean rice-based infant snacks. The mean iAs concentration was 65.6 µg/kg in rice powders and 54.0 µg/kg in rice snacks; 21% of rice powders and 6% of rice snacks exceeded the EU 100 µg/kg maximum level for infant foods. The author concludes that a Korean regulatory limit for iAs in infant rice products is urgently needed.

Key numbers

Infant rice powders (n=28, ready-to-cook): mean iAs 65.6 µg/kg (the text body also reports 65.7 µg/kg at the same position; abstract value preserved here), range 11.0–187.3 µg/kg, median 59.97 µg/kg. Roughly 17-fold variation across brands. 21% of samples exceeded the EU maximum level of 100 µg/kg for infant foods. One sample at 187.3 µg/kg exceeded even the 150 µg/kg maximum legislative level set for adult polished-rice consumption in China.

Infant rice snacks (n=31, puffed-type): mean iAs 54.0 µg/kg, range 15.9–120.9 µg/kg, median 45.3 µg/kg. 2 of 31 samples (6%) exceeded the EU 100 µg/kg infant-foods maximum level.

Regulatory comparison context cited in the paper: South Korea ML for iAs in polished rice 200 µg/kg; China ML for iAs in polished rice 150 µg/kg; EU iAs maximum level for rice and rice products effective January 2016 (paper reference 9); EU iAs maximum level for infant and young-children foods 100 µg/kg (paper reference 9); US FDA 2016 proposed action level for iAs in infant rice cereal 100 µg/kg (paper reference 14). At the time of the study, no Korean regulation applied to iAs in infant foods.

Method performance: LOD 0.015 pg and LOQ 0.05 pg on-column, equating to 0.15 and 0.5 µg/kg in sample; linearity r² > 0.999 for both As(III) and As(V) standards; intra-day RSD ≤ 6.5% and inter-day RSD ≤ 8.3%; spike recoveries in infant rice powder (n=2) and infant rice snack (n=2) samples ranged 94–119% across three levels. Standard reference material ERM-BC211 rice flour returned 120 ± 3.1 µg/kg against a certified value of 124 ± 11 µg/kg (94% accuracy).

Cross-country context cited by the author (not measured here): UK baby rice (Signes-Pastor et al. 2016, n=29) ranged 56–268 µg/kg iAs; Aberdeen UK baby rice (Meharg et al. 2008, n=17) median 110 µg/kg; US FDA 2013 baby rice survey (n=85) median 114 µg/kg with range 39–254 µg/kg; Spanish infant cereal products (Llorente-Mirandes et al. 2014, n=9) ranged 8.1–73.7 µg/kg with mean 23.0 µg/kg.

Evidence Fitness

Strong direct occurrence evidence for iAs in Korean ready-to-cook infant rice powders and Korean puffed infant rice snacks at the market-sampled level: validated method, standard reference material recovery, triplicate analysis, full distribution (mean, median, range) reported with n explicitly stated for both product groups. Supports both direct-evidence routing to baby-cereals-dry-rice-based and teething-and-snacks-rice-based and contextual support on arsenic and rice. Brand-attributed values are not provided in the source (consistent with the brand firewall); only group-level distributions are reported.

Methods

Analyte: inorganic arsenic. The author treats iAs as the sum of As(III) and As(V) after derivatization with 2,3-dimercapto-1-propanol (British Anti-Lewisite, BAL), which reduces As(V) to a single iAs-BAL complex prior to gas chromatography. Sample preparation: rice snacks were ground with a Hanil FM909T food grinder and passed through a 250 µm standard sieve; ready-to-cook rice powders were used directly. A 2.0 g sample was extracted with 20 mL of 1.764% (w/v) HNO₃ in a 95 °C water bath for 90 min in triplicate. A 1 mL aliquot was derivatized with 1.2 mL of 0.2% BAL solution at 50 °C for 30 min, and the iAs–BAL complex was extracted into 1 mL of dichloromethane.

Instrument: Shimadzu GC-2010Plus gas chromatograph coupled to a Shimadzu TQ8030 triple-quadrupole mass spectrometer. Column: Supelco SLB-5MS short non-polar capillary (6 m × 0.18 mm I.D., 0.18 µm film). Injector, MSD transfer line, and ion-source temperatures 300, 280, and 280 °C respectively. Oven program 50 °C (0.5 min) to 310 °C at 240 °C/min with 0.6 min hold. Helium carrier at 114.7 cm/sec linear velocity. Quantitative MRM transition m/z 212 → 165 at 15 V collision energy; qualitative transition m/z 212 → 107 at 35 V. Total run time 2.5 min, iAs retention 1.72 min.

Quantification: two-point standard-addition method with spiked As(III) at 10.0 and 30.0 ng/mL; the in-sample iAs concentration was back-extrapolated from the calibration line per Frenich et al. 2009 (paper reference 30). All samples prepared and analyzed in triplicate. Method validated against the SRM ERM-BC211 rice flour (94% of certified value recovered). Sodium arsenite (Merck) and disodium hydrogen arsenate heptahydrate (Wako) served as As(III) and As(V) calibration standards. Statistical analysis: one-way ANOVA with Tukey HSD post-hoc at α = 0.05 in SPSS 14.0 K.

Scope limitations the source itself acknowledges: this is a single-author monitoring study of market samples from South Korea only; brand identities and sampling sites are not disclosed; the rice powders and rice snacks were the only product categories surveyed (formula, purees, and other infant foods were not). The sample is a convenience purchase from local and online retail rather than a stratified market survey, and no information is given on growing region, cultivar, or production year of the source rice.

Implications

Direct occurrence evidence for the baby-cereals-dry-rice-based cell (Korean ready-to-cook infant rice powders, dry-as-sold native basis: n=28, mean 65.6 µg/kg iAs, range 11.0–187.3, median 59.97) and the teething-and-snacks-rice-based cell (Korean puffed rice infant snacks, as-sold native basis: n=31, mean 54.0 µg/kg iAs, range 15.9–120.9, median 45.3). Both cells are contributory inputs to any future pooled percentile computation for those product rows. Geographic scope is Korea only; pooling with US/UK/Spain data on the same product forms would require a multi-jurisdiction analytic decision rather than a single-paper update. The 21% exceedance of the EU 100 µg/kg infant-foods ML in the rice-powder group and the 6% exceedance in the rice-snack group are relevant for the regulatory-context narrative on arsenic but are exceedance counts against an external limit, not pooled percentiles. The Korean regulatory gap the paper documents (no Korean iAs limit for infant rice products at time of publication) is a fact about KR jurisdiction relevant to any KR-scoped regulation page.

Provenance notes

Springer Nature publication (Food Science and Biotechnology, Korean Society of Food Science and Technology / Springer). Online publication 12 December 2017; print issue Vol 27(2), April 2018. Paper accessed under copyright; PDF held privately in raw/Manual Fetch Discovery/. The author’s previous BAL-GC-MS/MS method paper (Kang, Jung, Jung 2016, Anal. Chim. Acta 934:231–238, paper reference 20) and a related ready-to-eat rice products survey (Jung, Kang, Jung, Ma 2018, Food Chem. 240:1179–1183, paper reference 21) are cited as the analytical method origin; these are separate prior papers and not duplicates of this study. The paper notes that an internal Korean Food & Drug Administration project report (Park SH et al. 2012, paper reference 24) had previously surveyed iAs in cereal-based infant formula (mixed grains and sorghums) in Korea but did not cover ready-to-cook rice powders or rice snacks; that report is not included as a separate wiki source here.

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