Overview
Newton and colleagues bought 473 whole pasteurised retail milks from 42 brands in South East England every month through 2019 and measured macrominerals, trace elements and potentially toxic elements by ICP-MS. The paper reports means for copper, iron, iodine, manganese, molybdenum and zinc by production system and month. Arsenic, cadmium, lead, chromium, nickel and mercury were almost always below the limits of quantification, so no concentrations for them are printed in the main text.
Key numbers
- Share of measurements below the limit of quantification: arsenic 99.8% (LOQ 5.8 µg/kg), cadmium 91.2% (0.6 µg/kg), lead 94.8% (3.5 µg/kg), mercury 100% (3.5 µg/kg) (Section 3.2.4).
- Copper mean 39.0 µg/kg in conventional, 37.7 in organic and 46.3 in channel island milk (Table 1).
- Zinc 3.59, 3.64 and 4.26 mg/kg by the same systems; iodine 95 µg/kg in May to 451 µg/kg in January (Tables 1-2).
Methods (brief)
Freeze-dried milk was microwave-digested and analyzed by ICP-MS in an accredited laboratory, with certified reference materials DORM-5 and skimmed milk powder ERM-BD150. Means are mixed-model predictions with a pooled standard error.
Evidence Fitness
A large, year-round retail survey of whole milk with good quality control. For the toxic elements it supports only a qualitative statement that UK retail whole milk is nearly always below low quantification limits; the toxic-element values sit in a supplementary figure not filed here. This is a proxy for reduced-fat milk (whole milk only), so the reduced-fat milk page is not linked. The file is the university repository copy of the published version.