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Effect of natural antimicrobials against Salmonella, Escherichia coli o157:h7 and Listeria monocytogenesCuervo Pliego, Mary Pia 15 May 2009 (has links)
Salmonella, Escherichia coli O157:H7 and Listeria monocytogenes are pathogens that have caught the attention of federal agencies and researchers due to their great economic impact when illnesses occur. To reduce the presence of these pathogens, different approaches have been used. However, since the global consumer’s demand for natural ingredients is steadily increasing, the investigation of the effectiveness of potential natural antimicrobials is necessary. In this study, the in vitro antimicrobial activity of Hibiscus sabdariffa L extracts against Salmonella, E. coli O157:H7 and L. monocytogenes was investigated. Furthermore, H. sabdariffa L and ε-polylysine were evaluated to reduce populations of Salmonella and E. coli O157:H7 in ground beef. The minimum inhibitory concentration (MIC) of H. sabdariffa L extracts against Salmonella and E. coli O157:H7 was 6,489 μg/mL and for L. monocytogenes, 5,309 μg/mL. The minimum bactericidal concentration (MBC) of H. sabdariffa L extracts against Salmonella, E. coli O157:H7 and L. monocytogenes was 19,467, 58,400 and 29,200 μg/mL, respectively. The exposure to 58,400 μg/mL of H. sabdariffa extract at 25 oC for 12 h resulted in reductions of more than 6.0 log CFU/mL for any of the 3 pathogens tested. Ground beef inoculated with S. Agona (GFP) and E. coli O157:H7 (RFP) was subjected to 5 decontamination treatments. Three of the treatments were using H. sabdariffa L and the remaining ε-polylysine. S. Agona (GFP) was reduced in 1.1 log cycles using 10% of ground H. sabdariffa L and E. coli O157:H7 (RFP) was reduced 0.9 log cycles using 400 ppm of ε-polylysine. If these natural antimicrobials are combined with current antimicrobial technologies to form a hurdle effect, higher pathogen reductions could be achieved. Reductions in the presence of pathogens in food may lead into reductions in the incidence of foodborne diseases.
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Effect of natural antimicrobials against Salmonella, Escherichia coli o157:h7 and Listeria monocytogenesCuervo Pliego, Mary Pia 15 May 2009 (has links)
Salmonella, Escherichia coli O157:H7 and Listeria monocytogenes are pathogens that have caught the attention of federal agencies and researchers due to their great economic impact when illnesses occur. To reduce the presence of these pathogens, different approaches have been used. However, since the global consumer’s demand for natural ingredients is steadily increasing, the investigation of the effectiveness of potential natural antimicrobials is necessary. In this study, the in vitro antimicrobial activity of Hibiscus sabdariffa L extracts against Salmonella, E. coli O157:H7 and L. monocytogenes was investigated. Furthermore, H. sabdariffa L and ε-polylysine were evaluated to reduce populations of Salmonella and E. coli O157:H7 in ground beef. The minimum inhibitory concentration (MIC) of H. sabdariffa L extracts against Salmonella and E. coli O157:H7 was 6,489 μg/mL and for L. monocytogenes, 5,309 μg/mL. The minimum bactericidal concentration (MBC) of H. sabdariffa L extracts against Salmonella, E. coli O157:H7 and L. monocytogenes was 19,467, 58,400 and 29,200 μg/mL, respectively. The exposure to 58,400 μg/mL of H. sabdariffa extract at 25 oC for 12 h resulted in reductions of more than 6.0 log CFU/mL for any of the 3 pathogens tested. Ground beef inoculated with S. Agona (GFP) and E. coli O157:H7 (RFP) was subjected to 5 decontamination treatments. Three of the treatments were using H. sabdariffa L and the remaining ε-polylysine. S. Agona (GFP) was reduced in 1.1 log cycles using 10% of ground H. sabdariffa L and E. coli O157:H7 (RFP) was reduced 0.9 log cycles using 400 ppm of ε-polylysine. If these natural antimicrobials are combined with current antimicrobial technologies to form a hurdle effect, higher pathogen reductions could be achieved. Reductions in the presence of pathogens in food may lead into reductions in the incidence of foodborne diseases.
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Improving liquid chemical intervention methods to control pathogens on fresh-cut fruits and vegetablesTroya, Maria Rosa 16 August 2006 (has links)
Factors that affect liquid chemical intervention methods of controlling pathogens
on fresh-cut produce were investigated. The relationship between produce tissue
structure (intercellular space, cell size, and cell distribution) and the sanitizing
effectiveness of liquid chemical treatment was studied. Experiments determined if
sanitizer contact with bacteria could be improved through the use of surfactants and
different application methods (drop application method, negative pressure differential,
and sonication). To test these factors, a model sanitizer, H2O2, and a model
microorganism: Salmonella Typhimurium, along with various fresh-cut produce (apple,
pear, carrot, and potato) were tested. Microscopic analysis revealed a very complicated
pore structure consisting of irregular capillaries. S. Typhimurium was found to survive in
all produce tested, and washing did not significantly reduced inoculated bacteria
regardless of the bacterial incubation time or produce type. The results showed that a 3%
H2O2 solution reduced S. Typhimurium in produce and the solutionÂs efficiency varied in
the following descending order: potato>apple>carrot>pear. In seven min treatments,
bacteria were reduced by 2.5 CFU/ml in potato, 2.3 CFU/ml in apple, 1.5 CFU/ml in
carrot, and 0.7 CFU/ml in pear. There was no direct evidence on how intercellular space,
its percentage or cellular distribution and shape affected efficiency, but some possibilites
were discussed. The rate and extent of liquid penetration, and how varying pore
diameter in each cell or air space prevent complete chemical treatment penetration were
also analyzed.
It was determined that bacterial density has a slight effect in bacterial reduction
but this depends on type of produce inoculated. The use of surfactants did not improve
bacterial reduction in either washing or chemical treatments, and neither did the use of drop application method or temperature differential. On the other hand, applying the
chemical treatment with a surfactant while using a sonicator did improve the treatmentÂs
efficiency. This thesis provides a number of factors to be considered when designing a
chemical treatment and a guideline for further research in areas such as rate and extent of
liquid chemical treatment penetration into fresh-cut produce.
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Who's on first unraveling the complexity of the United States' food and agricultural regulatory system in the realm of homeland security /Elliott, Gary Wayne. January 2009 (has links) (PDF)
Thesis (M.A. in Security Studies (Homeland Security and Defense))--Naval Postgraduate School, December 2009. / Thesis Advisor(s): Bergin, Richard ; Wollman, Lauren. "December 2009." Description based on title screen as viewed on January 28, 2010. Author(s) subject terms: Homeland security, agriculture, food, defense, Food and Drug Administration, Department of Agriculture, Department of Homeland Security, food safety, food defense, intelligence, model, comparative government, threats, terrorism, food security, conceptual model, Single Food Safety Agency. Includes bibliographical references (p. 133-143). Also available in print.
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An Examination of Foodborne Outbreaks of Salmonella Enteritidis in the United States, 1973-2008Wright, Ashton P 05 November 2010 (has links)
Salmonella is a common enteric pathogen and is the most frequently reported bacterial infection in the United States. The two most commonly reported serotypes causing human illness in the United States are Salmonella serotype Typhimurium and Salmonella serotype Enteritidis (SE). The incidence and number of foodborne outbreaks of SE started to increase in the 1970s and by 1994, SE was the most common Salmonella serotype reported to the Centers for Disease Control and Prevention (CDC). SE has been most commonly associated with consumption of shell eggs. Outbreak reports were obtained from the Foodborne Disease Outbreak Surveillance System (FDOSS) and analyzed. The number of outbreaks of SE has declined by 67% since 1990, likely as a result of the combined effect of on-farm interventions, public health policies, and food safety education messages. In addition to the decline in SE outbreaks, study findings demonstrate that there have been changes in the geographical distribution of SE outbreaks in the US. “Simple egg” foods and retail food settings have been the most commonly and consistently associated vehicles and food consumption and preparation settings with SE outbreaks in the US from 1973 to 2008.
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Identification of bacteria by infrared imaging with the use of focal plane array Fourier transform infrared spectroscopyPrévost Kirkwood, Jonah. January 2007 (has links)
The application of infrared imaging employing focal plane array Fourier transform infrared (FPA-FTIR) instrumentation for the identification of bacteria was investigated. FPA-FTIR spectroscopy was shown to provide new opportunities for bacteria identification with unprecedented reliability and throughput by allowing 102--103 FTIR spectra to be acquired simultaneously from surface areas of 90 x 90 to 200 x 200 mum with a spatial resolution of ∼6 mum. The combination of data redundancy and spatial resolution afforded by infrared imaging made it possible to acquire highly reproducible spectra from bacterial films. A protocol for enhancing the reliability of bacteria identification by transmission-mode FPA-FTIR spectroscopy was developed by optimizing spectral acquisition parameters, spectral processing and data analysis; using the differentiation of two Campylobacter species as a test case. The results for this test case were compared with those obtained from three alternate FTIR spectral acquisition modes. The optimized protocol was employed for the generation of a spectral database of foodborne bacteria, containing over 1,000,000 spectra acquired by infrared imaging of 36 species from 19 genera. The development of a modular hierarchical clustering (MHC) model, in combination with the use of a region selection algorithm, allowed all species in the database to be differentiated from each other down to the species level based on differences in their infrared absorption profiles. A validation study involving the identification of well-characterized isolates by comparison of their spectra to those in the database demonstrated the robustness of the MHC model. In a further study employing 44 strains of Clostridium botulinum, the discriminatory power of FPA-FTIR spectroscopy was compared with that of pulsed-field gel electrophoresis, and the region selection algorithm was applied to identify growth medium-independent spectral regions that allowed for the differentiation of Group I and Group II C. botulinum strains in two blind validation studies. The research carried out also demonstrated the high-throughput potential of bacteria identification by infrared imaging when combined with the use of a microarray system for sample deposition. Overall, the novel FPA-FTIR spectroscopy-based bacteria identification protocol developed in this work provides a rapid-response and reagent-free technique suitable for routine use in both food and clinical microbiology laboratories.
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A food safety education module for low income parentsGraetzer, Martha M. 08 September 1992 (has links)
Graduation date: 1993
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Food safety communication in Nevada needs assessment /Surendera Babu, Aruna. January 2006 (has links)
Thesis (M.P.H.)--University of Nevada, Reno, 2006. / "May 2006." Includes bibliographical references (leaves 83-87). Online version available on the World Wide Web.
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Quantitative detection of Salmonella enterica and the specific interaction with Lactuca sativa /Klerks, Michel M. January 2007 (has links) (PDF)
Thesis (Doctoral)--Wageningen University, The Netherlands, 2007. / Vita. "Prepositions (stellingen)" ([1] leaf) inserted. Includes bibliographical references. Also available via the Internet on the university's web site.
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Foodborne pathogens in poultry production and post-harvest controlNayak, Rajesh R. January 2000 (has links)
Thesis (Ph. D.)--West Virginia University, 2000. / Title from document title page. Document formatted into pages; contains x, 180 p. : ill. (some col.). Includes abstract. Includes bibliographical references.
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