Wednesday, July 25, 2012
Exhibit Hall (Rhode Island Convention Center)
Alejandro Soto-Marquez, Universidad Autonoma de Queretaro, Queretaro, Mexico
Salvador Villalobos-Reyes, Instituto Nacional de Investigaciones Forestales Agricolas y Pecuarias, Celaya, Mexico
Heriberto Godoy-Hernandez, Instituto Nacional de Investigaciones Forestales Agrícolas y Pecuarias, Celaya, Mexico
Ramiro Pacheco-Aguilar, Universidad Autonoma de Queretaro, Queretaro, Mexico
Montserrat Iturriaga, Universidad Autonoma de Queretaro, Queretaro, Mexico
Introduction: Traditionally, pest control and fertilization of the fields are carried out through the application of pesticides and inorganic fertilizers. However, in recent years the trend worldwide focus in reducing the use of these compounds. Biosolarization process is a non-chemical disinfection technique used to control soil pests and plant pathogens. The method is based in the approach of combining microbial degradation activity of complex substances that come from organic waste (plant residues, animal manure) and solarization that involves covering soil with a clear plastic film to trap solar radiation and accumulate heat. It is necessary to generate information regarding the effectiveness of biosolarization in the inactivation of foodborne pathogens.
Purpose: The purpose of the study was to study the efficacy of biosolarization in the inactivation of Escherichia coli and Salmonella inoculated in soil.
Methods: Soil was mixed with cattle, goat and sheep manure (120 ton/ha) and hydrated to field capacity. One group of samples was inoculated (ca. 7 log CFU/g) with Salmonella spp. resistant to rifampicin; another group of samples was inoculated with E. coli (ca. 6 log CFU/g) containing a gene to express the green fluorescent protein (GFP). Inoculated samples were stored at 45 and 25 °C for up to 6 weeks.
Results: At 45 °C (biosolarization) E. coli and Salmonella were not detected after four days of storage. At 25 °C both microorganisms survived for up to 6 weeks; at the end of the storage the decrease in the population of E. coli and Salmonella was 3 and 5 log CFU/g, respectively.
Significance: Biosolarization represents a viable alternative to inactivate foodborne pathogens such as Salmonella in the short term. Additionally, the treatment reduces the incidence of phytopathogens and increase the nutrient content in soil.
