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

Microbiological agents associated with childhood diarrhoea in the dry zone of Sri Lanka

Between March and July, 1987, faecal specimens from 371 diarrhoeal children reporting to four hospitals in the district of Kurunegala, Sri Lanka and from 121 controls with other diseases were investigated for enteric pathogens. All specimens were tested for Shigella spp, Salmonella spp and enteropathogenic Escherichia coli (EPEC). In addition, parasitic pathogens, heat labile enterotoxigenic Esherichia coli (ETEC LT), Campylobacter and rotavirus were sought among subsamples of the cases and controls. One or more pathogens were detected in the faecal specimens of 53.7% of the diarrhoeal children and 19.6% of the controls (P 0.10). Other pathogens had prevalence rates of less than 5%. Vomiting was associated with rotavirus diarrhoea (p < 0.001), and fever with shigellosis (p = 0.02). In view of the different transmission routes and characteristics of the most important pathogens detected in this study it appears unlikely that a single environmental intervention can solve the public health problem posed by diarrhoeal diseases in Sri Lanka.link_to_subscribed_fulltex