Persistence of Indicator and Pathogenic Microorganisms in Broccoli following Manure Spreading and Irrigation with Fecally Contaminated Water: Field Experiment

Abstract

In 2011 and 2012, trials consisting of experimental plots were carried out to evaluate the presence of pathogenic (Listeria monocytogenes, Salmonella) and prevalence of indicator (Escherichia coli) microorganisms in broccoli fertilized with liquid hog manure or mineral fertilizers and irrigated zero, one, or two times with E. coli-contaminated water. In 2011, results showed that E. coli contamination in broccoli heads was affected by the interval between irrigation and sampling (P = 0.0236), with a significant decrease between the first and third day following irrigation (P = 0.0064). In 2012, irrigation frequency significantly increased E. coli prevalence in broccoli samples (P = 0.0499). In 2012, E. coli counts in the soil were significantly influenced by the type of fertilizer applied, as plots receiving liquid hog manure showed higher bacterial counts (P = 0.0006). L. monocytogenes was recovered in one broccoli sample, but geno-serogrouping differentiated the isolate from those recovered in manure and irrigation water. The L. monocytogenes serogroup IIA, pulsotype 188 strain was found in six soil samples and in irrigation water applied 5 days before soil sampling. This study highlights the link between E. coli levels in irrigation water, irrigation frequency, and interval between irrigation and harvest on produce contamination. It also demonstrates that L. monocytogenes introduced into the soil following irrigation can persist for up to 5 days.

Preharvest Transmission Routes of Fresh Produce Associated Bacterial Pathogens with Outbreak Potentials: A Review

“…Certain laboratory experiments have been carried out to determine the efficacy of these waiting times and it was observed that the number of infectious bacteria such as E. coli O157:H7 and Salmonella spp. occurring on farm produce significantly reduced between 1 to 10 days of stoppage of irrigation and soil amendment [145,285,286,291,292,293]. Although some studies stated that some of the pathogens do not really die off but get induced into a dormant form, a state where the pathogens are viable but not culturable (VBNC) under stressful conditions [294], but returns to viable cells when favourable conditions return.…”

The Role of Stress and Stress Adaptations in Determining the Fate of the Bacterial Pathogen Listeria monocytogenes in the Food Chain

“…There was a greater chance of isolating L. monocytogenes after irrigation than rainfall and this chance was highest within 24 h of the event (Weller et al, 2015b). Other studies have confirmed similarly that irrigation is a risk factor for contamination of pre-harvest foods (Genereux et al, 2015; Weller et al, 2015a). This is often due to the contamination of the water source used for irrigation of the fields (Strawn et al, 2013; Genereux et al, 2015).…”

“…Other studies have confirmed similarly that irrigation is a risk factor for contamination of pre-harvest foods (Genereux et al, 2015; Weller et al, 2015a). This is often due to the contamination of the water source used for irrigation of the fields (Strawn et al, 2013; Genereux et al, 2015). Along with irrigation, the use of manure as a fertilizer can increase isolation of L. monocytogenes from produce production sites (Watkins and Sleath, 1981; Fenlon et al, 1996; Garrec et al, 2003).…”

ALLELOPATHIC EFFECTS OF Corymbia torelliana ON THE GERMINATION AND INITIAL DEVELOPMENT OF AGRICULTURAL AND FOREST SPECIES

“…As DTA podem ser causadas por diversos agentes como bactérias, fungos, vírus, parasitos, toxinas, prions, agrotóxicos e metais tóxicos. Estão geralmente associadas ao consumo de preparações prontas e vegetais frescos processados ou não GÉNÉREUX et al, 2015). SILVA, 2014).…”