Progress 04/01/03 to 03/30/09
Outputs
OUTPUTS: Alternative Processes and Antimicrobials for Juices: Apple cider and orange juice were inoculated with E. coli O157:H7 and Salmonella spp. to result in a very highly contaminated product. Contaminated juices were treated with food grade preservatives and then processed using technologies that are alternatives to thermal pasteurization (i.e., ultraviolet light and high pressure.) Combinations of preservatives and technologies that result in at least a 99.999 percent reduction in bacterial populations were identified. Shelf-stable apple and tomato juices were treated with a number of chemical preservatives to inhibit or inactivate the spoilage bacterium, Alicyclobacillus acidoterrestris. Preservatives with high antibacterial activity at low dose were identified. Combined Use of UV and Antimicrobials: The purpose of this study was to determine the efficacy of UV in combination with antimicrobials to reduce L. monocytogenes in fresh and used (spent) chill brines. Three different antimicrobials were used in combination with UV; citric acid (CA, 0.2 and 0.5 percent), dimethyl dicarbonate (DMDC, 250 and 500 ppm), and hydrogen peroxide (HP, 2000 and 4000 ppm). Brine was treated with UV alone, antimicrobials alone, and combination of UV and antimicrobials. For UV treatment, inoculated brine solution was exposed to UV in an Ultraviolet Water Treatment Unit (Peak output: 254 nm) at brine temperature of -1 degree C. Samples were withdrawn at regular intervals for 120 minutes. For antimicrobial-only (i.e., no UV) treatments, a specific concentration of antimicrobial was added in inoculated brine and samples were taken for 120 minutes. Dose Response to Ultraviolet Light (UV): The purpose of this research was to determine the minimum dose of UV (peak: 254 nm) required to inactivate L. monocytogenes (healthy and stressed) in water and a 9 percent NaCl solution using uridine as a chemical actinometer. L. monocytogenes strains were suspended in water and 9 percent NaCl solution, each containing 10-4 M uridine. Fourteen ml of suspension was irradiated for 0, 5, 10, 15, 20, 25, or 30 minutes using an Oriel photoreactor fitted with a filter to allow only UV light in the 254 nm range to pass to the sample. L. monocytogenes strains were acid stressed (pH 5.0), heat shocked (48 degrees C for 1 h), and made sulfanilamide resistant (512 micrograms/ml) and suspended in water and 9 percent NaCl solution, each containing 10-4 M uridine. Inactivation was evaluated by plating onto MOX and TSAYE, and enrichment in BHI. The absorbance of each sample was measured before and after irradiation, to calculate the dose of UV. High Pressure to Inactivate Norovirus: Murine norovirus (strain MNV-1), a propagable norovirus, was evaluated for susceptibility to high-pressure processing. Experiments with virus stocks were performed in Dulbecco's modified Eagle medium at room temperature (20 degrees C) and 5 degrees C over a pressure range of 350 to 450 MPa. PARTICIPANTS: Williams, R. C., Co-Principle Investigator; Department of Food Science and Technology, Virginia Tech, Blacksburg, VA Flick, G., Co-Principle Investigator; Department of Food Science and Technology, Virginia Tech, Blacksburg, VA McKinney, J., Ph.D. student; Department of Food Science and Technology, Virginia Tech, Blacksburg, VA DevKumar, G., Ph.D. student; Department of Food Science and Technology, Virginia Tech, Blacksburg, VA Parikh, P., Ph.D. student; Department of Food Science and Technology, Virginia Tech, Blacksburg, VA Whitney, B., M.S. student; Department of Food Science and Technology, Virginia Tech, Blacksburg, VA Quicho, J., M.S. student; Department of Food Science and Technology, Virginia Tech, Blacksburg, VA Hartman, A., M.S. and Ph.D. student; Department of Food Science and Technology, Virginia Tech, Blacksburg, VA The graduate students received intensive graduate training in food microbiology while working on this project. They attended professional meetings (Institute of Food Technologists and International Association for Food Protection) and presented research reports to audiences of varied backgrounds. TARGET AUDIENCES: Food processors who use or have interest in processes that do not require heat. Principle targe audiences include juice processors and ready-to-eat meat processors. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
Changes in Knowledge- Research: Six large projects encompassing more than 15 distinct studies have been completed. The resulting data has contributed new knowledge in the following areas: Different strains of pathogenic bacteria associated with foodborne outbreaks differ in resistance to high pressure processing (HPP). Among those tested, E. coli O157:H7 E009 and Salmonella Agona were most pressure resistant. The most effective antimicrobial tested in combination with HPP was DMDC having a 5.79 (125 ppm, E. coli) and 5.96 (62.5 ppm, Salmonella) log10 CFU/ml decrease directly following pressurization, respectively. Treatment of shelf-stable juices with nisin, lysozyme, cinnamic acid, and potassium sorbate prevented spoilage by Alicyclobacillus acidoterrestris. UV alone was much more effective in fresh brines than in spent brines. However, combinations of UV and dimethyl dicarbonate, citric acid, hydrogen peroxide, or ozone were more effective than UV alone, especially in spent brines. Acid and antibiotic-stressed L. monocytogenes were more resistant to UV in brines than "healthy" and heat-shocked cells. Furthermore, UV dose of 33.2 mJ/cm2 was found to correspond to greater than a 5 log reduction of L. monocytogenes in fresh brines. On frankfurters, results show that plant essential oils loaded onto zein coatings are effective against L. monocytogenes. Norovirus is inactivated by high pressure in Dulbecco's modified Eagle medium over a range of 350 to 450 MPa. This work is the first demonstration that norovirus can be inactivated by high pressure and suggests good prospects for inactivation of nonpropagable human norovirus strains in foods. The data collected through this research provides food processors with information to better utilize UV, HPP and antimicrobial agents to control bacterial and viral pathogens in foods. Education: Information gained from this research has been incorporated into graduate level food microbiology courses. As a result, students have demonstrated improved knowledge of L. monocytogenes contamination points and controls in RTE manufacturing; use of alternative processing and antimicrobials for fruit juices; and the use of high pressures to inactivate foodborne pathogens. Extension: Food processors have gained knowledge for improved decision-making in regard to control of foodborne pathogens.
Publications
- McKinney, J., R.C. Williams, G. Boardman, J. Eifert, and S. Sumner. 2009. Dose of UV Light Required to Inactivate Listeria monocytogenes in Distilled Water, Fresh Brine, and Spent Brine. J. Food Prot. 72(10): 2144-2150.
- McKinney, J., R.C. Williams, G. Boardman, J. Eifert, and S. Sumner. 2009. Effect of Acid Stress, Antibiotic Resistance, and Heat Shock on the Resistance of Listeria monocytogenes to UV Light When Suspended in Distilled Water and Fresh Brine. J. Food Prot. 72(8): 1634-1640.
- McKinney, Julie. 2008. Minimum ultraviolet light dose determination and characterization of stress responses that affect dose for Listeria monocytogenes suspended in distilled water, fresh brine, and spent brine. Dissertation. Virginia Tech collection.
- Dev Kumar, Govindaraj. 2008. Effect of ozone and ultraviolet irradiation treatments on Listeria monocytogenes populations in chill brines. Thesis. Virginia Tech collection.
- Parikh, Priti. 2007. Efficacy of ultraviolet light and antimicrobials to reduce Listeria monocytogenes in chill brines. Dissertation. Virginia Tech collection.
- Whitney, B., R.C. Williams, J. Eifert, J. Marcy. 2008. High pressures in combination with antimicrobials to reduce Escherichia coli O157:H7 and Salmonella Agona in apple juice and orange juice. J. Food Prot. 71(4):820-824.
- Whitney, B., R.C. Williams, J. Eifert, and J. Marcy. 2007. High pressure resistance variation of Escherichia coli O157:H7 strains and Salmonella serovars in tryptic soy broth, distilled water and fruit juice. J. Food Prot. 70(9):2078-2083.
- Kingsley, D., D. Holliman, K. Calci, H. Chen and G. Flick. 2007. Inactivation of a Norovirus by High-Pressure Processing. Appl. Environ. Micro. 73(2): 581-585.
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Progress 10/01/07 to 09/30/08
Outputs
OUTPUTS: Conducting Experimentation: L. monocytogenes strains N1-227 (hotdog batter), N3-031 (turkey franks), and R2- 499 (Ready-to-eat meat) were used to produce acid stressed (35 degrees C for 3 hrs in Trypticase Soy Broth with Yeast Extract, TSBYE, acidified to pH 5.0), heat shocked (Brain Heart Infusion, BHI, at 48 degrees C for 1 hour), and antibiotic resistant (512 micrograms/ml sulfanilamide) cells which were mixed in equal proportions and suspended in distilled water and 9% NaCl solution, each containing 10-4 M uridine. Fourteen milliliters of suspension was placed into a sterile quartz cell, and irradiated for 0, 5, 10, 15, 20, 25, or 30 minutes using an Oriel photoreactor fitted with a filter to allow only UV light in the 253.7 + or - 10 nm range to pass to the sample. The sample was held at 8 degrees C and continuously stirred during UV exposure. Inactivation was evaluated by serially diluting samples in 0.1% peptone, surface plating onto Modified Oxford Agar (MOX) and TSAYE, and by enrichment BHI; followed by incubation at 37 degrees C for 24-48 hrs. The absorbance of each sample was measured before and after irradiation, using a Shimadzu spectrophotometer (model UV-2101PC) to calculate the dose of UV. Dissemination: The results of this experiment were presented at the 2008 annual meeting of the International Association for Food Protection in Columbus, OH. PARTICIPANTS: McKinney, Julie S., Ph.D. (doctoral student at time of work), Eifert, Joseph D. (Associate Professor, FST, Virginia Tech) Boardman, Greg D. (Professor, CEE, Virginia Tech) TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Change in Knowledge: Acid stressed L. monocytogenes irradiated in water decreased by 5.81 log CFU/ml on MOX and 5.98 log CFU/ml on TSAYE and after exposure of 43.89 mJ/cm2 (30 min). Acid stressed L. monocytogenes irradiated in 9% NaCl decreased by 4.45 log CFU/ml on MOX and 5.95 log CFU/ml on TSAYE after UV exposure greater than 32.57 mJ/cm2 (30 min). Heat shocked L. monocytogenes irradiated in water decreased to below the detection limit (1 log CFU/ml) at UV doses greater than 13.14 mJ/cm2 (20 min) but was detected via enrichment after exposure of up to 24.78 mJ/cm2 (30 min). Heat Shocked L. monocytogenes irradiated in 9% NaCl decreased to below the detection limit after exposure to doses greater than 20.41 mJ/cm2 (30 min). Antibiotic resistant L. monocytogenes irradiated in water decreased by 5.92 log CFU/ml on MOX and 5.94 log CFU/ml on TSAYE after UV exposure greater than 70.33 mJ/cm2 (30 min). Antibiotic resistant L. monocytogenes irradiated in 9% NaCl decreased by 5.55 log CFU/ml on MOX and 5.36 log CFU/ml on TSAYE after UV exposure greater than 136.66 mJ/cm2 (30 min). Time significantly affected population estimates; as time of exposure to UV light increased, UV intensity, and dose increased, thereby significantly decreasing populations in each solution. There were no differences between population estimates based on media (MOX or TSAYE) or solution (distilled water or fresh brine). There were no differences between population estimates of acid stressed and antibiotic resistant or healthy and heat shocked. However, acid stressed and antibiotic resistant were more resistant to UV light than healthy and heat shocked L. monocytogenes.
Publications
- McKinney, J., R.C. Williams, S.S. Sumner, J.D. Eifert and G.D. Boardman. 2008. The Effect of Acid Stress and Heat Shock on the Minimum Ultraviolet Light Dose Required to Inactivate Listeria monocytogenes in Water and 9% NaCl. Abstract. IAFP 2008 Annual Meeting Book of Abstracts.
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Progress 10/01/06 to 09/30/07
Outputs
OUTPUTS: Three different antimicrobials were used in combination with UV: citric acid (CA, 0.2 and 0.5%), dimethyl dicarbonate (DMDC, 250 and 500 ppm), and hydrogen peroxide (HP, 2000 and 4000 ppm). For fresh brine studies, brine (8.0% w/v NaCl) was prepared and inoculated with a cocktail of three L. monocytogenes strains (approximately 6 log CFU/mL). Brine was treated with UV alone, antimicrobials alone, and combination of UV and antimicrobials. Inoculated brine solution was exposed to UV in an Ultraviolet Water Treatment Unit (Model: AMD 150B/1/2T D; Aquionics Inc., Peak output: 254 nm) fitted with an inline chiller to maintain brine temperature of -1 degrees C. Samples were withdrawn at regular intervals for 120 minutes. Enrichment was performed and suspect colonies were confirmed using API-Listeria. When treated with UV alone, L. monocytogenes population decreased from approximately 6 log CFU/mL to below the detection limit (i.e., 1 log CFU/mL) in 15 minutes with the reduction
rate of 0.87 log CFU/mL per minute. However, cells were detectable by enrichment through 120 minutes. The highest rate of decline (0.90 log CFU/mL per minute) was achieved by the combination of UV and 500 ppm DMDC (UV+500 ppm DMDC), which was not significantly different from the reduction rates of UV and UV+0.5% CA. UV+500 ppm DMDC reduced L. monocytogenes to the detection limit in 15 minutes and the organism was not detected by enrichment after 60 minutes. Though the reduction rate of UV+0.5% CA was not significantly lower than the rate of UV+500 ppm DMDC (P more than 0.05), the former treatment resulted in non-detectable levels more quickly (45 minutes) than the latter (60 minutes). Thus, based on enrichment studies UV+0.5% CA was the most effective treatment in reducing the population of L. monocytogenes in fresh brine. Moreover, when brine was treated with 0.5% CA alone the population decreased to below detection limit in 15 minutes with the rate significantly lower than UV+500
ppm DMDC and UV+0.5% CA (P less than 0.05). However, L. monocytogenes was not detectable by enrichment from 60 minutes. Spent brine is recycled brine that was obtained from a frankfurter processor after its maximum usage. Results of spent brine studies showed that when brine was treated with UV+4000 ppm HP and UV+2000 ppm HP, L. monocytogenes population decreased to the detection limit in 45 minutes and was not detected by enrichment from 120 minutes. These treatments were observed to be the most effective treatments with a reduction rate of 0.12 log CFU/mL per minute. The reduction rate of some other treatments such as, UV+250 and 500 ppm DMDC, UV+0.2% and 0.5% CA, and UV alone was not significantly different from UV+4000 and 2000 ppm HP. However, the population was detected through enrichment up to 120 minutes in all other treatments. The results of these studies indicate that combinations of UV and antimicrobial may be more effective than either treatment alone (except 0.5% CA
treatment) to process fresh and spent chill brines.
PARTICIPANTS: Priti P. Parikh. Graduate Student. Department of Food Science and Technology, Virginia Tech. Ms. Parikh developed skills as a food microbiologist and she learned research design, planning and implementation as a result of participation in this project.
TARGET AUDIENCES: Ready-To-Eat meat processors.
Impacts
Listeria monocytogenes is a known pathogen of concern in ready to eat meat products. The presence of the organism in these types of products results in the recall of some ready-to-eat meat products every year. The use of antimicrobial agents in combination with ultraviolet light in the treatment of chill brines used for ready-to-eat meat processors will aid in determining appropriate strategies to control this foodborne pathogen. Identification of appropriate antimicrobial levels in combination with alternative processing technologies for the treatment of fruit juices may provide juice processors with a economical means of complying with federal juice HACCP requirements.
Publications
- Parikh, P., R. Williams, J. Marcy, J. Eifert and K. Mallikarjunan. 2007. Ultraviolet Light and Dimethyl Dicarbonate to Reduce Listeria monocytogenes in Chill Brine. Abstract: IAFP Annual Meeting; Orlando, FL
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Progress 10/01/05 to 09/30/06
Outputs
The efficacy of ultraviolet light (UV) in combination with citric acid to reduce L. monocytogenes in chill brines was investigated. Fresh brine (60 L; 8.0 percent w/w NaCl) was inoculated with a L. monocytogenes cocktail (ca. 6 log CFU/ml). Citric acid (0.1 percent w/w) was added to inoculated brine and the solution was exposed to UV in an Ultra Violet Water Treatment Unit (Model: AMD 150B/1/2T D; Aquionics Inc., Erlanger, KY; Peak output: 254 nm) fitted with an inline chiller unit to maintain a brine temperature of -1 C during treatment. Samples were withdrawn at 0, 1, 5, 15, 30, 45, 60, 75, 90, 105, and 120 min. during treatment, serially diluted in 0.1 percent peptone, and surface plated onto Modified Oxford Agar. When L. monocytogenes was no longer detectable via direct plating, enrichment was performed in Brain Heart Infusion Broth. Suspect colonies on MOX were confirmed using API Listeria. When treated with UV alone, L. monocytogenes populations decreased from
ca. 6 log CFU/ml to below the limit of detection (1 log CFU/ml) within 5 min. However, L. monocytogenes was detectable by enrichment through 120 min. When treated with citric acid alone (i.e., no UV), populations decreased to below the detection limit in 30 min., but were detectable by enrichment through 120 min. When treated with UV and citric acid, L. monocytogenes decreased to the detection limit in 5 min. and was not detected by enrichment after 15 min. The results of this work indicate that combinations of UV and citric acid may be more effective than either treatment alone for the reduction of L. monocytogenes in chill brines.
Impacts
Listeria monocytogenes is a known pathogen of concern in ready to eat meat products. The presence of the organism in these types of products results in the recall of some ready-to-eat meat products every year. The use of antimicrobial agents in combination with ultraviolet light in the treatment of chill brines used for ready-to-eat meat processors will aid in determining appropriate strategies to control this foodborne pathogen. Identification of appropriate antimicrobial levels in combination with alternative processing technologies for the treatment of fruit juices may provide juice processors with a economical means of complying with federal juice HACCP requirements.
Publications
- Parikh, Priti, Robert C. Williams, Joseph D. Eifert, and Joseph E. Marcy. 2006. Efficacy of Ultraviolet Light and Citric Acid to Reduce Listeria monocytogenes in Chill Brine. Abstract. International Association of Food Protection Annual Meeting Program Book.
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Progress 10/01/04 to 09/30/05
Outputs
STUDY 1 - Preliminary data is currently being collected to determine the parameters for ultraviolet light and antimicrobial treatment of chill brines inoculated with Listeria monocytogenes. STUDY 2 - In this study, refrigerated (4 degrees C) pasteurized apple cider that contained no added preservatives was inoculated with E. coli ATCC 25922 and exposed to UV (peak output: 254 nm). The following chemical preservatives were added to apple cider either prior to or after UV exposure: dimethyl dicarbonate (75 and 150 ppm), hydrogen peroxide (75 and 150 ppm), potassium sorbate (1000 and 2000 ppm), and sodium benzoate (1000 and 2000 ppm). Following UV exposure and chemical preservative application, inoculated juices were stored at 4 degrees C for 72 hours. Samples were collected prior to and immediately after UV exposure and at 24, 48, and 72 hours of storage. At each sampling point, juice portions (0.1 ml) were serially diluted in peptone diluent (0.1 percent) and surface
plated onto Tryptic Soy Agar (TSA). Counts of the bacterial colonies were made 48 hours after incubating plates at 35 degrees C. Overall, reductions of E. coli were greater in cider treated with preservatives after UV processing than when preservatives were added prior to UV processing (P less than 0.05). Furthermore, dimethyl dicarbonate and hydrogen peroxide were more effective than potassium sorbate and sodium benzoate in reducing E. coli populations in conjunction with UV (P less than 0.05). When added prior to UV exposure, potassium sorbate was the least effective, allowing for the greatest survival (P less than 0.05). STUDY 3 - The effect of pressure on the log reduction of six strains of E. coli O157:H7 and five serovars of Salmonella enterica were investigated in tryptic soy broth, sterile distilled water and commercially sterile orange and apple juice. Samples were subjected to high hydrostatic pressure (HHP) at 300 and 550 MPa for 2 minutes at 6 degrees C, and then held for
24 hours at 4 degrees C following treatment. E. coli O157:H7 strain E009 was the most pressure resistant, having a decrease of only 0.77 log10 CFU/ml directly after pressurization in TSB. S. Agona was the most pressure resistant Salmonella serovar tested with a decrease of 3.79 log10 CFU/ml in TSB at 550 MPa. The two most pressure resistant cultures were then used in a subsequent study using HHP in conjunction with antimicrobials (dimethyl dicarbonate [DMDC] at 62.5 and 125 ppm, hydrogen peroxide at 150 and 300 ppm, cinnamic acid, potassium salt at 125 and 250 ppm, potassium sorbate [KS] at 500 and 1000 ppm and sodium benzoate [NaB] at 500 and 1000). For both E. coli O157:H7 and Salmonella, the most effective antimicrobial was DMDC having a 5.79 and 5.96 log10 CFU/ml decrease directly following pressurization, respectively. Other treatments that were significantly different from the samples treated with no antimicrobial were hydrogen peroxide, and NaB at 500 ppm for E. coli O157:H7
and a treatment of NaB at 1000 ppm for S. Agona. After 24 hours at 4 degrees C, S. Agona samples with added antimicrobials had a close to or above 5-log10 CFU/ml reduction.
Impacts
Development of recommnedations for the use of antimicrobial agents in combination with ultraviolet light in the treatment of chill brines will aid ready-to-eat meat processors in determining appropriate strategies to control the foodbrone pathogen, Listeria monocytogenes. Identification of appropriate antimicrobial levels in combination with alternative processing technologies for the treatment of fruit juices may provide juice processors with a economical means of complying with federal juice HACCP requirements.
Publications
- Quicho, Joemel. 2005. Efficacy of ultraviolet light in combination with chemical preservatives for the reduction of Escherichia coli in apple cider. Master of Science Thesis. Virginia Polytechnic Institute and State University.
- Whitney, Brooke. 2005. Efficacy of high pressure processing in combination with chemical preservatives for the reduction of Escherichia coli O157:H7 and Salmonella in apple juice and orange juice. Master of Science Thesis. Virginia Polytechnic Institute and State University.
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Progress 10/01/03 to 09/30/04
Outputs
During the current reporting year, data has been collected on the effect of several levels of antimicrobials (i.e., potassium sorbate, sodium benzoate, hydrogen peroxide, and dimethyl dicarbonate) in combination with ultraviolet light to reduce the populations of bacterial pathogens in apple cider. This data is currently being subjected to statistical analysis and interpretation. Data collection has also begun to determine the efficacy of High Presure Processing (HPP) in combination with antimicrobials. However, all HPP data collected to this point are considered to be preliminary.
Impacts
Identification of appropriate antimicrobial levels in combination with alternative processing technologies for the treatment of fruit juices may provide juice processors with a economical means of complying with federal juice HACCP requirements. Determination of pathogen survival in osmotically dehydrated fruit and factors that influence survival in such products, may encourage processing changes and prevent foodborne illness associated with consumption of related products. Finally, identification of appropriate antimicrobila agents for prevention of juice spoilage may allow fruit juice processors the reduce the incidence of product loss due to spoilage caused by Alicyclobacillus acidoterrestris.
Publications
- Ramasamy, Thilahavathy, Robert C. Williams, Joseph D. Eifert, and Susan S. Sumner. 2004. P218 Fate of Escherichia coli O157:H7 and Salmonella during Osmotic Dehydration and Subsequent Storage of Apples. International Association of Food Protection. Arizona. Program and Abstract Book. pp. 122.
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Progress 10/01/02 to 09/30/03
Outputs
Preliminary efforts are currently underway to determine appropriate levels of antimicrobials and alternative processes to inactivate disease-causing bacteria in fruit juices. Once appropriate levels of each parameter are identified data collection will begin. Studies to determine the effect of antimicrobial agents on the survival of the spoilage microorganism, Alicyclobacillus acidoterrestris, have been completed. Results indicate that nisin, lysozyme, cinnamic acid, and potassium sorbate may prevent A. acidoterrestris spoilage in juices or juice containing beverages. Studies conducted to determine the ability of Listeria monocytogenes to survive in fruit juices during refrigerated and temprature-abusive storage conditions revealed that the pathogen remained viable in white grape, apple, and orange juices for up to 12, 24 and 61 days, respectively. Studies performed to determine the fate of disease-causing bacteria during processing of osmotically dehydrated apples
have also been completed. The results of this study show that the E. coli O157:H7 and Salmonella are able to survive during processing of osmotically dehydrated fruit, but survival is influenced by the osmotic processing method used and the level of additive (i.e., CaCl2) utilized. Research efforts are on-going.
Impacts
Identification of appropriate antimicrobial levels in combination with alternative processing technologies for the treatment of fruit juices may provide juice processors with a economical means of complying with federal juice HACCP requirements. Determination of pathogen survival in osmotically dehydrated fruit and factors that influence survival in such products, may encourage processing changes and prevent foodborne illness associated with consumption of related products. Finally, identification of appropriate antimicrobila agents for prevention of juice spoilage may allow fruit juice processors the reduce the incidence of prodcut loss due to spoilage caused by Alicyclobacillus acidoterrestris.
Publications
- Hartman, A.D. 2003. Efficacy of antimicrobial treatments for the inactivation of Alicyclobacilus acidoterretris in fruit juices. Master of Science Thesis. Virginia Polytechnic Institute and State University.
- Hartman, A.D., R.C. Williams, S.S. Sumner, and B.W. Zoecklein. 2003. The efficacy of antimicrobial treatments for the inhibition of Alicyclobacillus acidoterrestris in apple and tomato juices. Annu. Mtg. Intl. Assoc. for Food Prot., New Orleans, LA, August 10-13.
- Piotrowski, C.L., R.C. Williams, S.S. Sumner, J.E. Marcy. 2003. Survival of Listeria monocytogenes in fruit juices during refrigeration and temperature-abusive storage. Annu. Mtg. Intl. Assoc. for Food Prot., New Orleans, LA, August 10-13.
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