A δ2H Isoscape of blackberry as an example application for determining the geographic origins of plant materials in New Zealand

Stable isotope signatures of deuterium, oxygen 18, and carbon 13 (δ2H, δ 18O, δ 13C) in imported apples available in the markets of Vietnam

This study examines whether fresh apples from the United States, New Zealand, and China sold in the markets of Vietnam can be distinguished based on the stable isotopic signatures of their water and carbon (δ²H, δ¹⁸O, and δ¹³C). The δ²H and δ¹⁸O in apples from the United States were found to average - 100.1 ‰ and - 10.5 ‰ vs VSMOW, respectively, lighter than those from New Zealand and China. In apples from China, the δ¹³C_VBDP averaged - 25.8 ‰, which is more enriched than apples from the United States and New Zealand. A clear distinction was shown in the δ²H, δ¹⁸O, and δ¹³C values in apple samples from the three regions based on the statistical treatment at a 95 % confidence level and p < 0.05. This method is reliable enough to control the import and export of agricultural products.

A bioavailable strontium (87Sr/86Sr) isoscape for Aotearoa New Zealand: Implications for food forensics and biosecurity

As people, animals and materials are transported across increasingly large distances in a globalized world, threats to our biosecurity and food security are rising. Aotearoa New Zealand is an island nation with many endemic species, a strong local agricultural industry, and a need to protect these from pest threats, as well as the economy from fraudulent commodities. Mitigation of such threats is much more effective if their origins and pathways for entry are understood. We propose that this may be addressed in Aotearoa using strontium isotope analysis of both pests and products. Bioavailable radiogenic isotopes of strontium are ubiquitous markers of provenance that are increasingly used to trace the origin of animals and plants as well as products, but currently a baseline map across Aotearoa is lacking, preventing use of this technique. Here, we have improved an existing methodology to develop a regional bioavailable strontium isoscape using the best available geospatial datasets for Aotearoa. The isoscape explains 53% of the variation (R² = 0.53 and RMSE = 0.00098) across the region, for which the primary drivers are the underlying geology, soil pH, and aerosol deposition (dust and sea salt). We tested the potential of this model to determine the origin of cow milk produced across Aotearoa. Predictions for cow milk (n = 33) highlighted all potential origin locations that share similar ⁸⁷Sr/⁸⁶Sr values, with the closest predictions averaging 7.05 km away from their true place of origin. These results demonstrate that this bioavailable strontium isoscape is effective for tracing locally produced agricultural products in Aotearoa. Accordingly, it could be used to certify the origin of Aotearoa’s products, while also helping to determine if new pest detections were of locally breeding populations or not, or to raise awareness of imported illegal agricultural products.