Carriage and Subtypes of Foodborne Pathogens Identified in Wild Birds Residing near Agricultural Lands in California: a Repeated Cross-Sectional Study.

Current California agricultural practices strive to comanage food safety and habitat conservation on farmland. However, the ecology of foodborne pathogens in wild bird populations, especially those avian species residing in proximity to fresh produce production fields, is not fully understood. In this repeated cross-sectional study, avifauna within agricultural lands in California were sampled over 1 year. Feces, oral swabs, and foot/feather swabs were cultured for zoonotic Salmonella spp., Escherichia coli O157:H7, and non-O157 Shiga toxin-producing E. coli (STEC) and characterized by serotyping and pulsed-field gel electrophoresis. Of 60 avian species sampled, 8 species (13.3%, bird groups of sparrows, icterids, geese, wrens, and kinglets) were positive for at least one of these foodborne pathogens. At the individual bird level, the detection of foodborne pathogens was infrequent in feces (n = 583; 0.5% Salmonella, 0.34% E. coli O157:H7, and 0.5% non-O157 STEC) and in feet/feathers (n = 401; 0.5% non-O157 STEC), and it was absent from oral swabs (n = 353). Several subtypes of public health importance were identified, including Salmonella enterica serotype Newport, E. coli O157:H7, and STEC serogroups O103 and O26. In late summer and autumn, the same STEC subtype was episodically found in several individuals of the same and different avian species, suggesting a common source of contamination in the environment. Sympatric free-range cattle shared subtypes of STEC O26 and O163 with wild geese. A limited rate of positive detection in wild birds provides insights into broad risk profile for contamination considerations but cannot preclude or predict risk on an individual farm.IMPORTANCE The shedding dynamics of foodborne pathogens by wild birds on farmland are not well characterized. This yearlong study sampled wild birds for foodborne pathogens within agricultural lands in northern California. There was a low prevalence of Salmonella spp., Escherichia coli O157:H7, and non-O157 Shiga-toxin producing E. coli (prevalence, 0.34% to 0.50%) identified in bird populations in this study. However, pathogens of public health importance (such as Salmonella Newport, E. coli O157:H7, and STEC O103 and O26) were identified in fecal samples, and two birds carried STEC on their feet or feathers. Identical pathogen strains were shared episodically among birds and between wild geese and free-range cattle. This result suggests a common source of contamination in the environment and potential transmission between species. These findings can be used to assess the risk posed by bird intrusions in produce fields and enhance policy decisions toward the comanagement of food safety and farmland habitat conservation

Densidade de plantio de cultivares de cenoura para processamento submetidas à adubações química e orgânica Planting density of carrot cultivars for industrialization under organic and chemical fertilization

O objetivo deste trabalho foi verificar a produtividade das cultivares de cenoura Alvorada e Carandaí em diferentes densidades de plantio utilizando-se adubações química e orgânica, visando a produção de matéria-prima para o processamento de cenouretes e catetinhos. Foram utilizadas as densidades: 16; 20; 24; 28 e 32 plantas por metro linear, sendo as parcelas compostas por 10 linhas transversais ao sentido do canteiro, com 1 m de comprimento entre si. O delineamento experimental utilizado foi de blocos casualizados em arranjo fatorial 2x2x5 (duas cultivares, dois tipos de adubação e cinco densidades de plantio) com quatro repetições. Foram avaliados: peso total de raízes, estimativa de produtividade, comprimento de raízes, raízes com diâmetro menor que 3,0 cm (%), raízes com ombro verde (%), sobras para o processamento (%), descarte (%) e severidade da queima das folhas. A colheita foi feita aos 104 dias após o plantio. O peso total de raízes e raízes com diâmetro inferior a 3,0 cm não foram influenciados pelo tipo de adubação. O aumento da densidade reduziu a produção de raízes com diâmetro superior a 3,0 cm e o comprimento médio das raízes. Quando utilizou-se adubação química ocorreu maior presença de raízes com ombro verde e a cultivar Alvorada apresentou as maiores porcentagens de raízes com esta característica.<br>In this research the yield of Alvorada and Carandaí carrot cultivars was verified, under different planting densities, submitted to organic and chemical fertilization, aiming to obtain roots with adequate characteristics for cenourete production (similar to baby carrot) and catetinho (mini ball form). Five planting densities were used: 16; 20; 24; 28 and 32 plants m-1) with four replications, in a total of 80 plots of 10 lines spaced 0,25 m from each other. The total root weight, average root length, roots with smaller diameter than 3,0 cm (%), roots with green superior part (%),leftovers for processing (%),discard (%) and the severity of leaf blight were evaluated. Plants were harvested 104 days after sowing. Total root weight and percentage of root diameter smaller than 3,0 cm were not influenced by the type of fertilization. Increasing the planting density resulted in a reduction of the root weight with a diameter over 3,0 cm as well as in the root length, independently of the cultivar. Using chemical fertilization resulted in more roots with green shoulder independently of the employed cultivar; but Alvorada presented higher percentages of green shoulder