Soil quality is usually determined by its physical-chemical characteristics without taking into account the bacterial communities that play a fundamental role in the chemical decomposition of plant nutrients. In this context, the objective of the study was to evaluate bacterial diversity in high Andean grassland soils disturbed with Lepidium meyenii cultivation under different gradients of use (first, second and third use) and crop development (pre-sowing, hypocotyl development and post-harvest). The sampling was carried out in the Bombón plateau in the central Andes of Peru, during the rainy and low water seasons, by the systematic method based on a specific pattern assigned in a geometric rectangular shape at a depth of 0 - 20 cm. The characterization of the bacterial communities was carried out through the metagenomic sequencing of the 16S rRNA. 376 families of bacteria were reported, of which it was determined that there was a significant change in bacterial composition and distribution in relation to use pressure. There were no major changes due to the development of Lepidium meyenii. The families most sensitive to use pressure and soil poverty indicators were Verrucomicrobiaceae, Acidobacteraceae and Aakkermansiaceae.

The rise in global consumption of fresh vegetables is a response to their nutrient-dense composition and low caloric content—key factors for optimising human metabolic health. This study evaluated the Quantitative Microbial Risk Assessment (QMRA) of Helicobacter pylori and enteric pathogens in fresh vegetables within the central highlands of Peru. The research integrated conventional microbiology, qPCR, and Monte Carlo simulations. The results revealed a high prevalence of Escherichia coli (83.7%), with a heterogeneous distribution where Huancayo presented the highest prevalence (95.5%) and Chupaca the lowest (68.2%). In contrast, pathogens such as H. pylori and Campylobacter jejuni showed marginal prevalences of 2.33% and 3.49%, respectively, with detections restricted to leafy and root vegetables at specific points of sale. Although biochemical tests indicated the presumptive presence of Helicobacter pylori, the qPCR results were negative, possibly due to the bacteria’s viable but non-culturable (VBNC) state. The QMRA model showed a highly skewed annual infection risk distribution, with E. coli presenting the highest risk: median Pann = 1.000 and 84.3% of simulations exceeding the WHO tolerable threshold of 10⁻⁴. For Salmonella Typhimurium and Shigella flexneri, 22.4% and 9.1% of simulations exceeded the same threshold, respectively. The results underscore the urgent need to implement traceability programs and improve agricultural practices across the evaluated provinces.