Recurring foodborne outbreaks, attributed to Escherichia coli O157:H7, Salmonella sp., and Listeria monocytogenes, have identified irrigation water as a potential source of contamination, and creating the necessity for safe irrigation water in produce cultivation, as emphasized by the Food Safety Modernization Act (FSMA). In response to this imperative, this study explored the efficacy of surfactant-modified zeolite (SMZ) enhanced with Cetrimonium bromide (CTAB) as a sustainable water purification solution for surface water. The SMZ was assessed to have the capacity to filter contaminated water with high loads of foodborne pathogens. A laboratory study was conducted using a 100 g SMZ column. A liter of phosphate-buffered saline (PBS) was inoculated for each pathogen at 6 log CFU mL-1 concentrations. The study found that SMZ modified with CTAB at a concentration exceeding 20% by weight, indicating the ratio of CTAB to the total mass of the modifying solution, could eliminate >6 log CFU mL-1 of Escherichia coli O157:H7 and Listeria monocytogenes and >2 log of Salmonella sp. Subsequent field testing in strawberry farms demonstrated the system’s effectiveness, displaying significant bacterial reduction when contrasted with unfiltered pond water and sand filtration. The SMZ was able to filter more than 4 log CFU mL-1, from surface irrigation water spiked with a nonpathogenic Escherichia coli strain. The results indicate that the SMZ filtration approach holds promise as a remediation tool to control the risks of foodborne disease outbreaks associated with agricultural water. | Brotes alimentarios han sido atribuidos a Escherichia coli O157:H7, Salmonella sp., y Listeria monocytogenes, y se ha identificado el agua de riego como una posible fuente de contaminación. Esto realza la necesidad de agua de riego segura en productos hortofrutícolas, como lo enfatiza la Ley de Modernización de la Seguridad Alimentaria (FSMA). En respuesta a este imperativo, este estudio exploró la eficacia de la zeolita modificada con surfactante (SMZ) modificada con bromuro de cetrimonio (CTAB) como una solución para la purificación de agua superficial. Se determinó que el SMZ tiene la capacidad de filtrar agua contaminada con altas cargas de patógenos transmitidos por alimentos. Se realizó un estudio de laboratorio utilizando una columna de SMZ de 100 g. Para cada patógeno, se inoculó un litro de solución salina tamponada con fosfato (PBS) a concentraciones de 6 log UFC mL-1. Los resultados revelaron que SMZ, con una concentración de CTAB al 20% por peso total de la solución modificadora, podría eliminar >6 log UFC mL-1 de Escherichia coli O157:H7 y Listeria monocytogenes y >2 log UFC mL-1 de Salmonella sp. Las pruebas de campo en granjas de fresas demostraron la efectividad del sistema, mostrando una reducción bacteriana en comparación con el agua de estanque sin filtrar o filtrada con arena. El SMZ pudo filtrar más de 4 log UFC mL-1 del agua de riego superficial inoculada con una cepa no patogénica de Escherichia coli. Los resultados sugieren que la filtración SMZ podría controlar riesgos de brotes por agua agrícola.

In Irapuato, Guanajuato, Mexico, strawberry crops represent an important source of jobs for many people, particularly women. Traditionally, the crop is fertilized with high a rate of N (350-500 kg N ha(-1)). Thus, the objectives in this study were 1) to quantify the nitrogen uptake derived from fertilizer by the crop through the 15N isotopic technique, and 2) to quantity the water productivity. A strawberry crop cv. Chandler was transplanted to the field and fertilized with 300 kg N ha(-1) as ammonium sulphate 1% 15N atoms excess. The fertilization was split in three applications of 100 kg N ha(-1) at 30, 91 and 157 days after transplanting (dat). The lowest N-efficiency occurred in the period 0-64 dat (7%). The berries always showed the lowest N-efficiency (< 1%). The N-efficiency occurred in stage 64-91 dat. The highest N uptake from fertilizer occurred during the periods 64-91, 128-157, and 188-219 dat. In relation to water, the results indicate "poor" water productivity. The highest value observed occurred between 157-188 dat and is directly related to peak biomass accumulation. The calculated value of water productivity is 1.6 m3 kg(-1) fruit. Our data illustrate the need to continue with studies focused on the optimization the N-fertilizer and water.

Universidad Nacional Agraria La Molina. Facultad de Agronomía. Departamento Académico de Suelos | La fresa (Fragaria x annanasa) es un cultivo de gran importancia económica para muchos agricultores del departamento de Lima, principalmente por el número de empleos que genera en la época de cosecha; sin embargo, el bajo nivel de tecnificación del sistema de producción y el desconocimiento del manejo adecuado del riego y la calidad del agua en el cultivo de fresa, conlleva al uso desmedido del recurso hídrico. Por ello, los objetivos de esta investigación fueron evaluar el efecto de tres niveles de humedad del suelo (60, 80 y 100% de la capacidad de campo (CC)), dos tipos de agua (La Molina y desionizada) y el uso del mejorador magnético del agua sobre el desarrollo y rendimiento de la fresa (Fragaria x annanasa) cv. San Andreas. Se realizó un diseño experimental completamente al azar con 12 tratamientos, cada tratamiento tuvo tres repeticiones con un total de 36 unidades experimentales. El agua desionizada generó los valores más altos en peso seco, extracción de nutrientes, contenido de humedad en hojas y peciolos y, frutos, producción, número de frutos por planta, peso y calibre de fruto, coeficiente de partición de biomasa (CPB) en frutos y raíz y eficiencia de uso de agua (EUA). El 100%CC logró mejores resultados en la producción, número de frutos por planta, CPB en frutos y EUA. La humedad del suelo a 80 y 100%CC no presentó diferencias significativas en el peso seco, extracción de nutrientes, contenido de humedad, peso y calibre del fruto; sin embargo los valores fueron más altos respecto al 60%CC. El uso del mejorador magnético tuvo un efecto positivo en el peso seco y CPB de la corona, extracción de nutrientes en los frutos, contenido de humedad en hojas y peciolos, número de frutos por planta y calibre del fruto | The strawberry is a crop of great economic importance for many farmers in the department of Lima, mainly because of the number of jobs it generates at harvest time; however, the low technological level of the production system and the lack of knowledge of the proper management of irrigation and the quality of the water in the strawberry crop, leads to the excessive use of water resources. Therefore, the aims of this research were to evaluate the effect of three levels of soil moisture (60, 80 and 100% of the field capacity (FC), two types of water (La Molina and deionized) and the use of the magnetic water improver on the development and yield of the strawberry. A completely randomized experimental design was carried out with 12 treatments, each one had three replications with 36 experimental units in all. The deionized water showed the highest values in dry weight, nutrients extraction, moisture content of leaves and petioles and, fruits, production, number of fruits per plant, weight and size of fruit and, biomass partitioning coefficients (BPC) in fruits and root and the water use efficiency (WUE). 100% FC gave the best results in the production, number of fruits per plant, BPC in fruits and WUE. Soil humidity at 80% and 100% FC did not show significant differences in dry weight, nutrients extraction, moisture content, and weight and fruit size; however, the values were higher in comparison to 60% FC. The use of the magnetized irrigation water had a positive effect on the dry weight and BPC of the crown, nutrients extraction in the fruits, moisture content in leaves and petioles, number of fruits per plant and size of the fruit | Tesis