Progress 10/01/14 to 09/30/17
Outputs
Target Audience:The main target audience for this project are consumers and the US food industry, which will benefit directly from the results of this research. The scientific community will benefit from the generated knowledge regarding the development of efficient in-package treatments. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?This project offered training opportunities for a postdoctoral associate and an undergraduate student. The postdoc was also able to benefit from professional development activities by participating at conferences and symposia. How have the results been disseminated to communities of interest?The results of this work have been communicated at conferences and symposia. Additionally, a scientific paper has been written and awaits publication. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Objective 1 and Objective 2: We did evaluate the potential for a PL dose (fluence) multiplication effect using different light reflective media. While some effects have been observed, particularly using aluminum. Consequently, aluminum was used to line the inside of the PL unit in follow-up experiments. Most importantly though, we did find out that PL treatments through either "UV transparent" polymeric and biopolymeric materials can be effective. Objective 3 and Objective 4: We conducted PL treatments on model (solid) surfaces inoculated with surrogates of foodborne pathogenic microorganisms, under the optimal conditions identified as a result of Objectives 1 and 2. We also designed PL treatments for surface decontamination of cheese, and an example of real food application. During the last year of the project, we prepared starch film, and irradiated them with different fluence levels (1.02 to 12.29 J/cm2) of Pulsed Light (PL). These films were used to package Cheddar cheese slices and different PL fluence level were applied to evaluate the capacity of the in-pack treatment to control / inactivate L. innocua on this product. We also evaluated the effectiveness of PL at a dose of 9.22 J/cm2 in combination with the antimicrobials sodium benzoate (SB) or citric acid (CA), on controlling L. innocua for Cheddar cheese slices packaged with the biodegradable films. PL combined with films containing CA in the formulation achieved an average L. innocua reduction on cheddar cheese slices of 4 log during storage at 4 °C. However, after 7 days of refrigerated storage the samples showed significant changes in physicochemical properties such as pH, mass loss and mechanical properties. Overall, the starch-based films with incorporated SB showed strong potential for use as physical barriers / packaging for cheese, and allow the application of a terminal, in-package PL treatment for microbial control. However, SB did not show antimicrobial effect in the concentration used in this study. Combining CA and PL promoted an additional antimicrobial effect against L. innocua, showing a reduction up to 4.5 log of this strain in Cheddar cheese. These results can be used as a basis for developing effective antimicrobial control measures able to mitigate post-process contamination in cheese or other food products.
Publications
- Type:
Journal Articles
Status:
Awaiting Publication
Year Published:
2017
Citation:
J. O. de Moraes, S. T. Hilton, C. I. Moraru. 2018. Combination of Pulsed Light and Antimicrobial Films in the Improvement of Sliced Cheddar Cheese Safety and Quality during Storage
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Progress 10/01/15 to 09/30/16
Outputs
Target Audience:The main target audience for this project are consumers and the US food industry, which are expected to benefit directly from the results of this research. The scientific community, particularly microbiologists and food scientists, will benefit from the generated knowledge regarding the development of efficient in-package treatments. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?One MS student and one postdoctoral associate were trained as part of the project. They also provided training and mentoring to two undergraduate students, who will continue the project in the next few months. How have the results been disseminated to communities of interest?The PI, MS student and postdoctoral associate have reported our research findings through various seminars and conference presentations, at both local and national level. What do you plan to do during the next reporting period to accomplish the goals?In the next phase of the project, we will continue to seek ways to improve the effectiveness of PL treatment, primarily through the selection of packaging materials and effective antimicrobials.
Impacts
What was accomplished under these goals?
1. Factors that affect and may improve the effectiveness of PL treament To address Objectives 1 and 2, we investigated the effect of environmental related factors, namely temperature and reflectivity, on the bactericidal effectiveness of PL treatment. Temperature did not affect PL inactivation of E. coli or P. fluorescens, but a modest synergistic effect between PL and temperature was observed for L. innocua treated at 50 °C. At low temperatures and fluence levels, the gram-positive L. innocua was the most PL resistant of the three strains, followed by the gram-negative E. coli and P. fluorescens, respectively. Differences in sensitivities disappeared at higher temperatures and fluence levels. For all strains and treatment temperatures, the Weibull model was able to accurately describe PL inactivation kinetics. The effect of UV-reflectivity on PL treatments was also investigated. A clear liquid substrate was inoculated with L. innocua and then exposed to PL in UV-reflective and non-UV-reflective sample containers, respectively. The reductions achieved using UV-reflective and non-UV-reflective containers were 7.83 ± 0.41 log CFU and 6.41 ± 0.32 log CFU, respectively. Our data indicates that PL does not seem to be greatly affected by temperature within the range of 5 °C to 40 °C, although slight increases of PL effectiveness may be obtained in some cases by conducting the treatment at a higher temperature. Additionally, through the use of UV-reflective sample containers PL effectiveness can be enhanced by taking advantage of a UV fluence multiplication effect in liquids. 2. Design of effective in package Pulsed Light (PL) treatments through biodegrabale packaging films. To address Objective 4, we evaluated the effectiveness of PL combined with antimicrobials on controlling Listeria innocua, a surrogate for L. monocytogenes, and the effect of this treatment on the physicochemical properties of cheddar cheese slices during refrigerated storage. PL combined with CA films achieved average L. innocua reductions on cheddar cheese slices of 4 log during storage at 4 °C. However, after 5 days of refrigerated storage samples showed significant changes in physicochemical properties, which need to be addressed. These results can be used as a basis for developing effective antimicrobial control measures able to mitigate post-process contamination in cheese or other food products.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2016
Citation:
Hilton S. T., de Moraes, J.O., and Moraru C.I. 2017. Effect of sublethal temperatures on Pulsed Light inactivation of bacteria. Innovative Food Science and Emerging Technologies. 39, 49-54. DOI: 10.1016/j.ifset.2016.11.002
- Type:
Theses/Dissertations
Status:
Published
Year Published:
2016
Citation:
Sheena Hilton. 2016. Environmental related factors that influence pulsed light inactivation of bacteria. MS Thesis. Cornell Graduate School.
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2016
Citation:
S.T. Hilton, A., J. O. de Moraes and C.I. Moraru. 2016. Environmental related factors that influence Pulsed Light inactivation of bacteria. IAFP Annual Meeting, St. Louis, Missouri, August 2016.
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2016
Citation:
J. O. de Moraes, S. T. Hilton, and C. I. Moraru. 2016. Combination of Pulsed Light and Antimicrobial Films for Improving the Safety and Quality of Cheese during Storage. Conference of Food Engineering, Columbus, OH, September 2016.
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Progress 10/01/14 to 09/30/15
Outputs
Target Audience:The primary beneficiaries of this project will be consumers and the food industry from New York State and the U.S. at large. Food processors and retailers will be empowered with a novel intervention strategy against foodborne pathogens. It is expected that the results of this project will help food companies improve the safety of their products, which will ultimately reduce the incidence of foodborne illness and thus benefit the health of consumers and will minimize economic losses due to recalls and loss of reputation. Another direct beneficiary will be food safety community, particularly researchers from Academia or industry that are interested in alternative methods for food decontamination. The graduate student involved in this project will be exposed to the most recent issues that confront the safety of the food supply and, besides learning specific experimental techniques, will understand how research can be used to develop highly effective pathogen intervention strategies. Changes/Problems:As mentioned before, since some of the fluence multiplication effects could not be replicated, we added an investigation of theeffect of temperature on PL inactivation, as this is also expected to increase the effectiveness of PL treatment. What opportunities for training and professional development has the project provided?The project provided training opportunities for both a graduate student (MS), and an undergraduate student. The graduate student was directly involved in planning the work, and also executed the experiments and analyzed the data. The undergraduate student was primarily involved, independently or together with the graduate student, in both the experimental work and data analyses. How have the results been disseminated to communities of interest?
Nothing Reported
What do you plan to do during the next reporting period to accomplish the goals?We will continue to execute the experimental plan as originally proposed. In addition, we added an investigation of theeffect of temperature on PL inactivation, and this work is currently in progress.
Impacts
What was accomplished under these goals?
Objective 1: Build a systematic understanding of the PL dose (fluence) multiplication effect observed in prior experiments, using different media (water, various coated and not coated solid barriers such as transparent packaging materials, glass, quartz) and PL conditions. The effect on both total PL fluence and PL spectrum will be evaluated. We have conducted screening of a wide range of commercial UV reflective coatings, and determined their spectral absorption and transmission properties. Despite being marketed as "UV reflective", none of them were in fact behaving as such. We have also evaluated the existence of the fluence multiplication effect observed in the past through a thin layer of water, but under the conditions tested this has not been confirmed. The only material for which UV reflectivity of the substrate seemed to increase inactivation was Aluminum packaging. A thin layer of liquid sample inoculated with L. innocua (used as a surrogate for L. monocytogenes), contained in either a glass chamber or a UV reflective aluminum dish, was treated with PL doses ranging from 0.4 to 14.9 J/cm2. Survivors were recovered, and inactivation was quantified by standard plate counting. Treatments were replicated and inactivation data was evaluated statistically. A statistically significant difference (p<0.05) was achieved between inactivation in non-UV reflective (6.41±0.32 log) vs. UV-reflective (7.83±0.41 log) containers. Objective 2: Determine the optimal conditions that allow maximization of PL fluence and PL penetrations for surface treatments. Currently, we are conducting an investigation of theeffect of temperature on PL inactivation, as moderately warm temperatures may favor inactivation. Work on this objective is currently in progress.
Publications
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