|E. coli can survive for a long time on composted soils|
Germany is fatally sick. There is a lethal elephant in the room. This is that elephant:
“Use of animal wastes in fertilization of fresh fruits and vegetable plots significantly increased the risk of E. coli contamination in fresh produce grown in semi-organic and organic farms.”
The article is:
Association of farm management practices with risk of Escherichia coli contamination in pre-harvest produce grown in Minnesota and Wisconsin
Use of animal wastes in fertilization of fresh fruits and vegetable plots significantly increased the risk of E. coli contamination in fresh produce grown in semi-organic (OR = 12.9, 95% CI = 2.9–56.3, P-value less than 0.0001) and organic (OR = 13.2, 95% CI = 2.2–61.2, P-value less than 0.0001) farms (Table 4). Although composting did not affect the E. coli prevalence in semi-organic and organic produce, ageing of non-composted manure for more than 6 months contributed to a significant reduction of the risk (OR = 4.2 95% CI = 1.7–12.3, P-value = 0.005) among organically produced fruits and vegetables. Semi-organic and organic farms used various types of animal wastes such as chicken, hog, horse and cattle manure. Among these different manure types, use of cattle manure for fertilization of produce crops increased the risk of E. coli contamination by approximately 7-fold (OR = 7.4, 95% CI = 1.6–36.8, P-value = 0.003). Farmers who used animal wastes for fertilization applied manure either in the Spring or in the Fall or both in Spring and Fall. However, these different times of application of manure application did not have any significant effect on the E. coli prevalence in semi-organic and organic produce.
Several reports have found that some of the farm-level practices for handling and treating animal manure before their application as fertilizer might reduce the survival of contaminating bacteria in manure and in agricultural soil, in which manure had been amended as a fertilizer ([Hutchison et al., 2004], [Kudva et al., 1998] and [Lung et al., 2001]). Thus a major portion of the survey’s questionnaire was meant to collect information on manure-handling and treatment practiced by the semi-organic, organic and conventional produce growers who took part in this study.
During the two-year study, less than half of the conventional growers used animal manure for fertilization of their crops, while 70 to 90% of organic and semi-organic farmers applied animal manure for fertilization. This finding was expected as organic growers are not allowed to use most of the chemical fertilizers that conventional growers can use (AMS/USDA, 2000). Although the majority of the conventional farmers did not use animal waste as fertilizer, only 57% of the manure users composted animal manure before using it as fertilizer. As many as 70% of the semi-organic and almost all the organic farmers who used manure fertilizer applied composted manure.
Our findings, both during the present study and in a previous study, showed that only 1.5 to 2.5% of pre-harvest conventional produce had detectable E. coli contamination ([Mukherjee et al., 2004] and [Mukherjee et al., 2006]). This low number of positive samples prevented any risk-factor analyses involving conventional farms. However, among the 6 conventional farms which had at least one E. coli contaminated sample, 4 used manure-based fertilizers. In this study, only semi-organic and organic farms were included in the analyses of farm-level risk-factors associated with greater prevalence of E. coli. Among these two farm types, users of animal waste as fertilizer were at a significantly greater risk of E. coli contamination in their produce compared to those who did not use manure fertilizer (Table 4).
Ageing of animal wastes before their application as fertilizer was used by several of the participating farmers. Ageing of animal manure for less than 6 months increased the risk of E. coli contamination by more than four folds in organic produce (Table 4). However, this risk-factor did not show a significant effect on E. coli prevalence in semi-organic produce. Hutchison et al. (2004) reported that spreading livestock manure on the top of agricultural soil and let it age without mixing them into the soil significantly reduced counts of pathogenic bacteria such as E. coli O157:H7, Salmonella enterica, Listeria monocytogenes, and Campylobacter jejuni.
Association of farm management practices with risk of Escherichia coli contamination in pre-harvest produce grown in Minnesota and Wisconsin
Avik Mukherjee, Dorinda Speh and Francisco Diez-Gonzalez.
Food Science and Nutrition Department, University of Minnesota, St. Paul, Minnesota 55108, USA
South West Research and Outreach Center, University of Minnesota, Lamberton, Minnesota 56152, USA
International Journal of Food Microbiology
Volume 120, Issue 3, 15 December 2007, Pages 296-302
Microbiological analyses of fruits and vegetables produced by farms in Minnesota and Wisconsin were conducted to determine the prevalence of Escherichia coli in pre-harvest fruits and vegetables. During the 2003 and 2004 harvest seasons, 14 organic (certified by accredited organic agencies), 30 semi-organic (used organic practices but not certified) and 19 conventional farms were sampled to analyze 2029 pre-harvest produce samples (473 organic, 911 semi-organic, 645 conventional). Before each harvest season, a farmer survey was conducted to collect relevant information on farm management practices that might affect the risk of E. coli contamination in fresh produce. The use of animal wastes for fertilization of produce plants increased the risk of E. coli contamination in organic (OR = 13.2, 95% CI = 2.2–61.2, P-value less than 0.0001) and semi-organic (OR = 12.9, 95% CI = 2.9–56.3, P-value less than 0.0001) produce significantly. Improper ageing of untreated animal manure significantly increased this risk in organic produce (OR = 4.2 95% CI = 1.7–12.3, P-value = 0.005) grown using such manure as a fertilizer. Organic growers who used cattle manure for fertilization of their crops showed significantly greater risk of contamination with the E. coli (OR = 7.4, 95% CI = 1.6–36.8, P-value = 0.003), compared to those who used other types of manure-based fertilizer. In Minnesota, organic and semi-organic produce collected from the southeastern (SE) part of the state were at a significantly greater risk of E. coli contamination (OR = 3.45, 95% CI = 1.8–35.2, P = 0.008), compared to those collected from farms located in the southern (S) regions of the state. In Wisconsin, organic and semi-organic produce collected from the southern (S) cluster of farms were at approximately 3-times greater risk of E. coli contamination (OR = 2.67, 95% CI = 1.3–9.4, P = 0.004), compared to those grown in the northern (N) cluster of farms.
Keywords: Organic foods; Produce; Farm management; Pre
-harvest practices; Risk-factors; Prevalence; Escherichia coli
Further relevant papers
Bad Seeds – Again – This time E. coli O104:H4
POSTED BY BILL MARLER ON JUNE 25, 2011
appears to be a highly resilient pathogen possessing the capability to adapt easily to environmental stresses. While most human cases of E. coli O157 related food poisoning have been associated with the consumption of contaminated meat and dairy products, there is also evidence that human infection has occurred through the ingestion of contaminated soil, fruit and vegetables and drinking water. In this review the potential threat to human health posed by the application of contaminated organic wastes to soil and possible strategies for reducing the amount of pathogen entering the food chain are highlighted.
Internalization of human pathogens within growing salad vegetables.
Warriner K, Ibrahim F, Dickinson M, Wright C, Waites WM.
Biotechnol Genet Eng Rev. 2003;20:117-34.
Department of Food Science, University of Guelph, Guelph, Ontario, Canada N1G
Enterohemorrhagic Escherichia coli O157:H7 present in radish sprouts.
Itoh Y, Sugita-Konishi Y, Kasuga F, Iwaki M, Hara-Kudo Y, Saito N, Noguchi Y,
Konuma H, Kumagai S.
Appl Environ Microbiol. 1998 Apr;64(4):1532-5.
Department of Biomedical Food Research, National Institute of Infectious
Diseases, Shinjuku-ku, Japan.
Using cultivation, immunofluorescence microscopy, and scanning electron
microscopy, we demonstrated the presence of viable enterohemorrhagic Escherichia
coli O157:H7 not only on the outer surfaces but also in the inner tissues and
stomata of cotyledons of radish sprouts grown from seeds experimentally
contaminated with the bacterium. HgCl2 treatment of the outer surface of the
hypocotyl did not kill the contaminating bacteria, which emphasized the
importance of either using seeds free from E. coli O157:H7 in the production of
radish sprouts or heating the sprouts before they are eaten.
Internalization of bioluminescent Escherichia coli and Salmonella Montevideo in
growing bean sprouts.
J Appl Microbiol. 2003;95(4):719-27.
Warriner K, Spaniolas S, Dickinson M, Wright C, Waites WM.
Division of Food Sciences, School of Biosciences, University of Nottingham,
AIMS: Investigate the interaction of bioluminescent Escherichia coli and
Salmonella Montevideo with germinating mung bean sprouts.
METHODS AND RESULTS: E. coli or Salm. Montevideo introduced on mung beans became
established both internally and externally on sprouts after the initial 24 h
germinating period. In both cases the inoculated bacterium formed the predominant
microflora on the sprouted beans throughout. From the bioluminescent profile of
inoculated sprouting beans, bacterial growth was found to be in close proximity
to the roots but not on the hypocotyls. Clumps (biofilms) of cells with low
viability were observed within the grooves between epidermal cells on hypocotyls.
Treatment with 20,000 ppm sodium hypochlorite removed the majority of bacteria
from the surface of hypocotyls although nonviable single cells were occasionally
observed. However, viable bacteria were recovered from the apoplastic fluid, and
extracts of surface-sterilized sprouts indicating that the internal bacterial
populations had been protected. This was confirmed using in situ
beta-glucuronidase staining of surface-sterilized sprouts where cleaved enzyme
substrate (by the action of internalized E. coli) was visualized within the plant
CONCLUSIONS: E. coli or Salmonella present on seeds become internalized within
the subsequent sprouts and cannot be removed by postharvest biocidal washing.
SIGNIFICANCE AND IMPACT OF THE STUDY: Mung bean production should be carefully
controlled to prevent contamination occurring in order to minimize the health
risk associated with raw bean sprouts.
Survival of Escherichia coli O157:H7 in the rhizosphere of maize grown in waste-amended soil.
Exploring the benefits of organic nutrient sources for crop production and soil quality. Rosen, C.J. ; Allan, D.L. (2007)Horttechnology, 17, 4, pp 422-430
Soil quality is generally improved with application of organic nutrient sources, but careful management is required to avoid environmental risks of nitrate (NO3) leaching and phosphorus accumulation.
Provided that nutrient supply is equal, yields with organic sources tend to be similar to those with inorganic sources. However, lack of available nitrogen (N) that is synchronous with plant demand often limits yields in organic cropping systems. ….
Phytonutrient content also may be affected by differences in pest control strategies among cropping systems regardless of nutrient source. There is a slight, but significantly, increased risk of produce contamination by Escherichia coli and other enteric bacteria contamination on produce when organic nutrient sources are used, but if proper guidelines are followed, contamination with the lethal serotype O157:H7 does not appear to be a major concern. Appropriate management of organic inputs is critical to achieving potential benefits for crop production and soil quality.
One potential risk for people consuming produce grown with manure or manure-based composts is an increased exposure to enteric pathogens (Buck et al., 2003). The bacteria of concern are Escherichia coli, Salmonella spp., and Listeria monocytogenes. E. coli and Salmonella are in animal gastrointestinal tracts and consequently in manure, whereas L. monocytogenes is in decaying plant residues, soil, and animal manure. Consumption of produce contaminated with the E. coli serotype O157:H7 can in some cases cause death in people with weak immune systems. Numerous outbreaks of gastrointestinal disease have been linked to consumption of fresh fruit and vegetables; however, the source of contamination can occur at various stages of production through actual sale of the ﬁnal product. Although organic nutrient sources are not the only source of bacterial contamination, precautions in handling manure and manure compost need to be taken. To reduce the risk of contaminated produce, certiﬁed organic methods require that manure applied to ﬁelds must either be properly composted before application or produce for human consumption cannot be harvested for at least 90 d after application for edible portions of the crop not in direct contact with the soil and 120 d for edible portions in direct contact with the soil (USDA, 2000). Speciﬁc procedures that maintain temperatures in the pile to kill the pathogens must be followed during the composting process…
Loncarevic et al. (2005) reported that 8.9% of 179 organically grown lettuce samples collected from 12 producers in Norway were contaminated with E. coli, but only 2.2% of the samples were considered to have high enough levels to cause foodborne illness. The serotype O157:H7 and Salmonella were not detected in any of the samples. Listeria monocytogenes serogroups 1 and 4 were isolated from 1.1% of the samples. In a study to determine the potential for
contamination with E. coli serotype O157:H7, Johannessen et al. (2005) transplanted lettuce seedlings into soil fertilized with manure inoculated with E. coli O157:H7. After 50 d, the serotype was not detected in any parts of the lettuce leaves or roots; however, indigenous E. coli was detected sporadically on lettuce leaves… Based on these studies, it appears that there is a slight, but signiﬁcant, increased risk of produce being contaminated with E. coli and other enteric bacteria when organic nutrient sources are used. However, contamination with the O157:H7 serotype resulting from use of organic nutrient sources does not appear to be a major concern.