Progress 03/15/09 to 03/14/14
Outputs
OUTPUTS: Seven serotypes of pathogenic Shiga toxin-producing Escherichia coli were studied to determine if their growth and survival properties differed significantly from the prototype STEC E. coli O157:H7. Findings from these studies were disseminated: 1) at the Food Research Institute annual meeting that is attended by government, industry and academic professionals, 2) by webinar in a UW-Madison seminar series, 3) at the International meeting of Food Protection in Anaheim, CA, and 4) at the Raper Symposium coordinated by the Department of Bacteriology. PARTICIPANTS: Asst Professor Dorte Dopfer, SVM, UW-Madison (co-PI); Professor A. C. L. Wong, UW-Madison (co-PI); Jihun Kang, Associate Research Specialist; and Thom Mand, M.S. Graduate Student. TARGET AUDIENCES: The information from these studies will assist industry and regulatory agencies in determining appropriate, effective control procedures. PROJECT MODIFICATIONS: None
Impacts
Non-O157 STEC: Shiga-toxin producing E. coli can cause illness in the young, the elderly and the immunocompromised. Although the majority of STEC causing human illness in the U.S. are serotype O157:H7, CDC estimates that about a third of STEC infections in the U.S. are caused by non-O157:H7 serotypes. However, this is likely an underestimate because of the challenges in identification of non-O157 strains. Reports from public health surveillance studies in many (U.S.) states and from other countries indicate that sporadic cases of non-O157 STEC greatly outnumber outbreak cases. Data on 75 outbreaks caused by non-O157 STEC were tabulated and the relative importance of different vectors was presented in a pie chart. Many non-O157 STEC serotypes are associated with cattle and other ruminants and outbreaks have been traced to contact with animals, consumption of contaminated food and water, and person to person contact. Non-O157 STEC have been detected in meat, dairy products, coastal shellfish, and produce and they are also present in some surface waters and drinking water sources. Interventions for control of STEC range from different diets fed to ruminants, treatments for drinking water, vaccines for livestock, slaughterhouse interventions, and environmental control with sanitizers. Interventions for foods include thermal treatments, high pressure, addition of organic acids and other anti-microbials. We established an effective process for the production of fermented meats, i.e., pepperoni, to ensure that sufficient reductions of non-O157 STEC were achieved. Progress was made on the development of analytical methods for detection of non-O157 STEC including a PCR-based array detection system for genes encoding shiga toxins, other virulence factors, and serotype specific antigens. Studies of the growth and survival characteristics of non-O157 STEC demonstrated variation between serotypes and strains and indicated that risk assessments based upon data collected with E. coli O157:H7 should be adequate for control of non-O157 STEC. The information from these studies will assist industry and regulatory agencies in determining appropriate, effective control procedures.
Publications
- Jeong, K. W., M. Y. Kang, J. Kang, D. J. Baumler, and C. W. Kaspar. 2011. Feeding chitosan microparticles reduces Escherichia coli O157:H7 shedding in cattle. Applied and Environmental Microbiology 77:
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Progress 01/01/09 to 12/31/09
Outputs
OUTPUTS: The survival of four serovars of Salmonella enterica under desiccation conditions was investigated to determine the variation in this survival trait between strains and serovars. Scientific literature and government (U.S., Canadian, European, Australian, Japanese) sources were searched for information on epidemiological investigations of cases and outbreaks of illness caused by non-O157:H7 shiga toxin-producing E. coli (STEC), particularly during the past ten years. PARTICIPANTS: Ellin Doyle, co-PI; Jihun Kang, associate research specialist; Thomas Mand, M.S graduate student; Rigina Whitemarsh, undergraduate researcher; Amy Wong, co-PI. TARGET AUDIENCES: Some of the findings were presented at the Food Research Institute annual meeting in April and as part of the Raper Symposium coordinated by the Department of Bacteriology. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Outbreaks of Salmonella involving low-moisture foods has raised questions about the ability of Salmonella to persist in these food products. We studied the survival of four Salmnonella serovars in conditions with reduced available water (water activity, 0.92) where the sodium chloride and sucrose were used to reudce the water activity. Two storage temperatures were investigated (15C and 30C). Salmonella survival varied betwen serovars and strains. At lower temperature (15C), the survival of Salmonella serotypes was significantly greater than at 30C. Studies are currently in progress to understand the underlying mechanisms of the variation in desiccation tolerance. Non-O157 STEC: Shiga-toxin producing E. coli can cause illness in the young, the elderly and the immunocompromised. Although the majority of STEC causing human illness in the U.S. are serotype O157:H7, CDC estimates that about a third of STEC infections in the U.S. are caused by non-O157:H7 serotypes. However, this is likely an underestimate because of the challenges in identification of non-O157 strains. Reports from public health surveillance studies in many (U.S.) states and from other countries indicate that sporadic cases of non-O157 STEC greatly outnumber outbreak cases. Data on 75 outbreaks caused by non-O157 STEC were tabulated and the relative importance of different vectors was presented in a pie chart. Many non-O157 STEC serotypes are associated with cattle and other ruminants and outbreaks have been traced to contact with animals, consumption of contaminated food and water, and person to person contact. Non-O157 STEC have been detected in meat, dairy products, coastal shellfish, and produce and they are also present in some surface waters and drinking water sources. Interventions for control of STEC range from different diets fed to ruminants, treatments for drinking water, vaccines for livestock, slaughterhouse interventions, and environmental control with sanitizers. Interventions for foods include thermal treatments, high pressure, addition of organic acids and other anti-microbials. Analytical methods for detection of non-O157 STEC include PCR detection system for genes encoding shiga toxins, other virulence factors, and serotype specific proteins and immunoassays for shiga toxin proteins and specific O antigens. Some types of enrichment procedures and culture media may aid in screening bacterial isolates. The information in this white paper may aid industry and regulatory agencies in determining appropriate, effective control procedures. Important further research needs were described.
Publications
- No publications reported this period
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