Progress 10/01/08 to 09/30/12
Outputs
OUTPUTS: The present study evaluated the efficacy of phenolic constituent carvacrol and lauric arginate (LAE) against a three strain mixture of Salmonella spp. in ground turkey with the following objectives: (a) to determine the temperature dependent efficacy of carvacrol and LAE against a three strain mixture of Salmonella spp.; (b) to evaluate the antimicrobial efficacy of carvacrol and LAE at varying concentrations in three different ground turkey samples with varying composition (i.e. 15%, 7% and 1% fat content) against a mixed Salmonella spp. and total microbial load; and (c) to determine the synergistic action of carvacrol and LAE against three strain mixture of Salmonella spp. in ground turkey. In this study, low concentrations of carvacrol (0.025%-0.2%) and lauric arginate (25-200 ppm) were tested at 4C, 22C and 45C in a broth model, and higher concentrations of carvacrol (0.1% to 5%) and lauric arginate (LAE; 200 to 5000 ppm) were tested individually and in combination at 4C in three different ground turkey samples (with 15%, 7% and 1% fat content) for their effectiveness against three-strain mixture of Salmonella. A low concentration of 25 ppm LAE or 0.025% carvacrol had no effect on Salmonella in a broth model, but their mixture showed a synergistic action by reducing 6 log CFU/ml Salmonella counts to a non-detectable level within 30 min exposure. FDA recommended 200 ppm LAE was not sufficient for Salmonella reductions in ground turkey when applied internally. High concentrations of 2000-5000 ppm LAE or 1% to 2% carvacrol were needed to reduce Salmonella counts by 2 to 5 log CFU/g in ground turkey by internal application. No specific relationship existed between fat content and LAE or carvacrol concentrations for Salmonella reductions. For example, 2000 ppm LAE could reduce Salmonella counts by 4 log CFU/g in 1% fat containing turkey samples but very similar ~1.5 log CFU/g reductions in both 7% and 15% fat containing ground turkey samples. For the total microbial load, about 2000 ppm of LAE or 2% of carvacrol treatments were needed to achieve 2-3 log CFU/g reductions in different turkey samples. A mixture of 1% carvacrol and 2000 ppm LAE exhibited a synergistic action in ground turkey containing 7% fat by reducing the Salmonella counts by 4 log CFU/g which was not found with individual antimicrobial treatments. PARTICIPANTS: R. Nannapaneni, A. Oladunjoye, K. Soni, M.W. Shilling, J. Silva, W. B. Mikel, R. H. Bailey, B. Mahmoud, C. Sharma. This research provides practical information to help poultry industries in Mississippi for enhancing the food safety of ground poultry products. This project also provides extensive research training to our graduate students so they are able to perform independent research. TARGET AUDIENCES: Poultry Industries in Mississippi, USDA-FSIS, and National Integrated Food Safety Initiative PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
The continuous association of Salmonella in retail poultry products suggests that even if pre-harvest strategies can reduce Salmonella persistence, other control measures against this pathogen at the postharvest processing steps are very important. LAE is a FDA approved food preservative at concentrations up to 200 ppm of product weight. With respect to determining the efficacy of LAE, only a limited numbers of studies have been performed so far and the majority of the studies focused on L. monocytogenes as the target organism. These studies indicated that the effect of LAE is short term with a maximum bactericidal activity observed within the first 24 h against the targeted pathogen while remaining bacteria were able to survive and proliferate during long term storage. Moreover, the majority of these studies were performed on the intact food substrates such as whole ham, frankfurter or cheese. However, the results from our study indicates that the 200 ppm LAE is not sufficient to meaningfully reduce the Salmonella counts when applied internally as part of a product formulation in ground turkey. In the past, single antimicrobials were routinely used for controlling food safety associated risks. However, recently the focus has shifted to identifying the ideal mixtures of different antimicrobials that can provide a broad spectrum of antimicrobial activity while reducing the need for higher antimicrobial concentrations. In this study, we observed a synergistic action between sublethal concentrations of LAE and carvacrol when used in a combination in both broth and ground turkey models. We also observed a synergistic effect between LAE and carvacrol in 7% fat ground turkey samples. The individual treatments of LAE at 2000 ppm or carvacrol at 1% did not result in any appreciable reductions in mixed strain Salmonella counts; however, when combined together, they reduced the Salmonella counts to less than 1 log CFU/g in 7% ground turkey samples from the 5 CFU/g of initial load. Since our findings in this study show that antimicrobial activity of both LAE and carvacrol can be significantly improved at a higher temperature, future studies are needed to evaluate the individual and combined effect of these two GRAS antimicrobial treatments during the cooking step to determine if these antimicrobial can be used at a low level that would meet FDA limit and sensory acceptability. Further studies are also needed to understand the mechanisms of synergistic activity between carvacrol and LAE against Salmonella spp.
Publications
- Oladunjoye, A., Soni, K.A., Nannapaneni, R., Schilling, M.W., Silva, J.L., Mikel, W.B., and Bailey, R.H. 2012. Effect of Fat Concentration on the Efficacy of Lauric Arginate and Carvacrol in Reducing Salmonella spp. in Ground Turkey, Abstract No. 035-65, IFT 2012 Annual Meeting, Las Vegas, NV, June 25-28, 2012.
- Oladunjoye, A., Soni, K.A., Nannapaneni, R., Schilling, M.W., Silva, J.L., Mikel, W.B., and Bailey, R.H. 2012. Effect of Temperature on Salmonella Typhimurium and S. enterica Biofilm Formation and Their Control by Essential Oils, Abstract No. 035-69, IFT 2012 Annual Meeting, Las Vegas, NV, June 25-28, 2012.
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Progress 01/01/11 to 12/31/11
Outputs
OUTPUTS: Food processing technologies are challenged by the ability of Listeria monocytogenes to adapt to stress environments. Farmed fish contain Listeria on gills, skin and viscera. Presence of Listeria in fish products vary from 10 to 20%. Listeria appears on cleaned surfaces and nearly 1/3 of processing plants commonly isolate this pathogen. Presence of this pathogen is indicative of increased possibility of occurrence in finished products. There is a need for the development of alternative antimicrobial technologies for the destruction of Listeria in high-risk processing environments. Our work illustrates the potential of naturally occurring plant-derived essential oils for the reduction of Listeria on catfish fillets. Plant-derived oils were tested to eliminate biofilms of Listeria based on their concentration, contact time and age. Screening of nine different oils using a disk-diffusion assay suggested that thyme, oregano and carvacrol had the highest antimicrobial activity. Further screening against 21 different strains representing all 13 serotypes indicated some strain-specific variations in their antimicrobial activities. For the planktonic cells of Listeria at 107 CFU/ml, the MIC's and MBC's of thyme, oregano and carvacrol were 0.05% which was 2-10 times lower than the concentrations that were needed to kill biofilm cells. For 1-day-old biofilm cells produced in the polystyrene microtiter plates, 0.1% concentrations of thyme, oregano and carvacrol oils were needed to eliminate 7 logs CFU/well. On stainless steel coupons, 0.5% concentration of thyme, oregano and carvacrol was adequate to yield complete elimination of 4-day-old biofilms yielding 7 logs CFU/coupon of Listeria. These findings indicate that these oils are potential candidates for use to eliminate Listeria biofilm cells on stainless steel surfaces. In the project's second phase, antimicrobial activity of essential oils was determined on fresh fillets against a four strain mixture representing serotypes 1/2b, 3b, 4b and 4c that were predominantly isolated from processing environments. Essential oils of thyme, oregano and carvacrol exhibited concentration and time dependent responses in broth against Listeria. The other three oils, lemon, orange and tangerine, at 0.5% showed listeriostatic effect in which 4 logs CFU/ml of the initial Listeria load was unchanged at 4C in 10 days whereas 1% concentrations of these oils were listericidal in a time dependent manner. Dipping treatment of fillets in 2% carvacrol solution reduced Listeria to an undetectable level from their initial load of 5 logs CFU/g. Dipping in 5% thyme or oregano yielded only 2 log CFU/g reduction. Dipping treatment with 2% carvacrol also decreased the microbial load from fillets by ~5 logs CFU/g but there was only a ~2 log CFU/g reduction with 2% thyme or a non-significant reduction with the 2% oregano dipping treatment. During the 10-day study, Listeria counts were non-detectable in fillets treated with 2% carvacrol. These results show that carvacrol is highly effective in controlling Listeria on raw catfish fillets. PARTICIPANTS: The following individuals were participants in this project - Rama Nannapaneni, Monil Desai, Kamlesh Soni, Wes Schilling, and Juan Silva. Essential oils This research provides practical information to help catfish and salmon industry processors in Mississippi for enhancing the microbial quality of catfish products. This project also provides extensive research training to our graduate students so they are able to perform independent research. TARGET AUDIENCES: Catfish Processors in Mississippi, Salmon Processors in Mississippi, USDA-FSIS, and National Integrated Food Safety Initiative. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
According to the current data provided by NASS (2011), the overall sales for catfish growers in United States last year was reported as 403 million U.S. dollars, in which the four southern states of Mississippi, Alabama, Arkansas and Texas accounted for 94% of the overall sales. Catfish has a short shelf life of 8-10 days and because of its highly perishable nature, if not preserved properly, can lead to huge economic losses. The new 2008 farm bill legislation (PL 110-246) signed into law on June 18, 2008 extends United States Department of Agriculture Food Safety Inspection Service jurisdiction to include domestic and imported farm raised catfish. This legislation may lead to new federal regulations on microbiological requirements across aquaculture products based on risk analysis data. Although, catfish products are very rarely associated with any major foodborne outbreaks, but due to the high prevalence of L. monocytogenes in catfish processing environments, there is a potential for L. monocytogenes cross contamination during handling and preparation. Several physical and chemical strategies have been evaluated for the control of L. monocytogenes on catfish. Chlorine at 200 ppm did not result in any significant reduction of L. monocytogenes or total microbial counts on catfish fillets. Our findings suggest that the essential oils of thyme, oregano and carvacrol are highly effective against diverse strains of L. monocytogenes representing different serotypes and that essential oils can be effectively used to inactivate the L. monocytogenes biofilms. The essential oils of thyme, oregano and carvacrol exhibited concentration and time dependent responses against L. monocytogenes. Dipping treatment of catfish fillets in 2% carvacrol solution for 30 min at 4C reduced L. monocytogenes to an undetectable level from their initial load of 5 log CFU/g. Dipping treatment with 2% carvacrol also decreased the total microbial load from catfish fillets by ~5 log CFU/g. During the 10-day shelf life of catfish fillets, L. monocytogenes counts were non-detectable in fillets treated with 2% carvacrol. These results show that carvacrol which is an active ingredient of essential oils is highly effective in controlling L. monocytogenes growth on raw catfish fillets. In summary, our work shows that the essential oils are effective natural antimicrobials against L. monocytogenes in the catfish processing environments and in catfish fillets.
Publications
- Desai, M., Soni, A.K. and Nannapaneni, R. 2011. Effect of essential oils in reducing Listeria monocytogenes biofilms on stainless steel coupons. Abstract No. 037-24, IFT 2011 Annual Meeting, New Orleans, June 11-14, 2011.
- Desai, M., Oludunjoye, A., Soni, K. and Nannapaneni, R. 2011. Reduction of Listeria monocytogenes on raw catfish fillets using essential oils. Abstract No. 251-04, IFT 2011 Annual Meeting, New Orleans, June 11-14, 2011.
- Desai, M., Soni, K.A., Nannapaneni, R., Schilling, W. and Silva, J. 2012. Reduction of Listeria monocytogenes biofilms on stainless steel surfaces by essential oils. Journal of Food Protection (Manuscript # JFP-11-517 submitted on November 23, 2011).
- Desai, M., Soni, K.A., Nannapaneni, R., Schilling, W. and Silva, J. 2012. Reduction of Listeria monocytogenes in fresh catfish fillets by essential oils. Journal of Food Science (Manuscript # JFS-2011-1415 submitted on Nov. 23, 2011).
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Progress 01/01/10 to 12/31/10
Outputs
OUTPUTS: Listeria monocytogenes continues to be a problem in raw salmon and cold-smoked salmon products. The control or elimination of L. monocytogenes contamination in raw salmon is a first critical step for enhancing the safety of finished cold-smoked salmon that does not contain adequate listericidal steps. Several authors have reported the prevalence of L. monocytogenes in raw fish including salmon in the range of 0.1% to 25%. However, the levels of L. monocytogenes contamination are usually low and limited to 0.1 to 10 CFU/g at the initial stage of contamination, with only sporadic possibilities of this pathogen being isolated in high numbers. The intervention strategies for the L. monocytogenes control on raw salmon are inadequate, including chemical treatments such as chlorine, chlorine dioxide, acidified sodium chlorite or ozone. One promising approach for L. monocytogenes control is the use of bacteriophages as an anti-listerial agent. Recently, U.S. Food and Drug Administration (FDA) approved the bacteriophage preparations (Listex P100) for all raw and ready-to-eat foods at levels not to exceed 10^9 power PFU (plaque forming units)/g. Since there is no effective method for the control of L. monocytogenes on raw salmon fillets, we evaluated the efficacy of phage Listex P100 on raw salmon fillet tissues for L. monocytogenes biocontrol as a function of: (i) phage dose, (ii) phage contact time, and (iii) storage temperature and storage time. Also, biofilm formation in food processing facilities serves an important reservoir for pathogenic and spoilage bacteria and consequently, L. monocytogenes biofilms are major source of its contamination in ready-to-eat food products. We evaluated the efficacy of phage P100 against L. monocytogenes preformed biofilms on the stainless steel coupon surfaces. Our research findings on the potential applications of bacteriophage P100 against raw or cold salmon products or against biofilms of L. monocytogenes were shared National Integrated Food Safety Initiative (NIFSI). Another high-risk ready-to-eat food product for L. monocytogenes contamination is Queso fresco cheese (QFC). It is a high moisture Mexican-style soft cheese that has been classified within FDA's cluster 1 of ready-to-eat food products which indicates that it is one of the highest risk foods with respect to L. monocytogenes contamination. L. monocytogenes control measures for QFC during its cold storage are inadequate as this soft cheese has been frequently associated with Class 1 recalls due to L. monocytogenes contaminations. In this study, GRAS lauric arginate was evaluated for its antimicrobial effectiveness against L. monocytogenes cold growth in milk and QFC. Our research findings with lauric arginate were shared with Dairy Management Inc. and Southern Dairy Foods Research Center at North Carolina State University. PARTICIPANTS: R. Nannapaneni, K. Soni, M.W. Shilling, V. Jackson and S. Hagens Bacteriophage research has been conducted in collaboration with EBI Food Safety in Netherlands. This research provides valuable information to help catfish and salmon industry members in Mississippi as well as research training to our graduate students so they are able to perform independent research. Lauric arginate research has been conducted in collaboration with Dairy Management Inc. (DMI) and Southern Dairy Foods Research Institute at North Carolina State University. This research provides valuable information for the Queso freso cheese manufactures in the USA as well as research training to our graduate students so they are able to perform independent research. TARGET AUDIENCES: Salmon Processors in Mississippi, Catfish Processors in Mississippi, USDA-FSIS, and National Integrated Food Safety Initiative, Queso Fresco Cheese Manufacturers in the USA, Dairy Management Inc. (DMI), USDA-FSIS. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
We previously published the anti-listerial activity of GRAS bacteriophage Listex P100 (phage P100) on raw catfish fillets. In study, we determined the antilisterial activity of P100 on the surface of raw salmon fillet tissue against L. monocytogenes serotypes 1/2a and 4b. In a broth model system, phage P100 completely inhibited L. monocytogenes growth at 4 degrees C for 12 days, at 10 degrees C for 8 days and at 30 degrees C for 4 days at all three phage concentrations of 10^4, 10^6 or 10^8 PFU/ml. On raw salmon fillet tissue, a higher phage concentration of 10^8 PFU/g was required to yield a 1.8, 2.5 and 3.5 log10 CFU/g reductions of L. monocytogenes from its initial loads of 2, 3 or 4.5 log10 CFU/g at 4 degrees C or 22 degrees C. Over the 10-days of storage at 4 degrees C, L. monocytogenes growth was inhibited by phage P100 on the raw salmon fillet tissue to as low as 0.3 log10 CFU/g versus normal growth of 2.6 log10 CFU/g in the absence of phage. Phage P100 remained stable on the raw salmon fillet tissue over a 10-day storage period with only a marginal loss of 0.6 log10 PFU/g from an initial phage treatment of 8 log10 PFU/g. In another study, 21 different L. monocytogenes strains representing 13 different serotypes, were treated with Listex P100 (P100) to reduce L. monocytogenes population under planktonic and biofilm mass conditions. Based on CFU (colony forming units) quantifications of selected strains, phage P100 treatment reduced the L. monocytogenes counts by 5-6 logs in culture conditions. On stainless steel coupon surfaces there were 5.4 log reductions in L. monocytogenes populations following 24 h phage treatment. These findings illustrate that the GRAS bacteriophage Listex P100 is listericidal on raw salmon fillets or raw catfish and against biofilms of L. monocytogenes. In another study, GRAS lauric arginate (LAE) at concentrations of 200 ppm and 800 ppm were evaluated for effectiveness in reducing Listeria monocytogenes cold growth in whole milk, skim milk and QFC at 4 degrees C for 15 to 28 days. When a 4 log CFU/ml of L. monocytogenes was inoculated in whole milk or skim milk, the reduction of L. monocytogenes was approximately 1 log10 CFU/ml after 24 h with 200 ppm LAE. When 800 ppm LAE was added to whole or skim milk, the initial 4 log10 CFU/ml of L. monocytogenes was non-detectable following 24 h and no growth of L. monocytogenes was observed for 15 days at 4 degrees C. With the surface treatment of 200 ppm or 800 ppm LAE on vacuum packaged QFC, the reductions of L. monocytogenes within 24 h at 4 degrees C were 1.2 and 3.0 log10 CFU/g, respectively. Also, the overall growth of L. monocytogenes in QFC was decreased by 0.3-2.6 and 2.3-5.0 log10 CFU/g with 200 ppm and 800 ppm LAE, respectively, compared to untreated controls over 28 days at 4 degrees C. Sensory tests revealed that consumers could not determine a difference (P > 0.05) between QFC samples that were treated with 0 and 200 ppm LAE, the FDA approved level of use in foods. LAE shows the promise for potential use in QFC since it exerts initial bactericidal activity against L. monocytogenes cold growth at 4 degrees C without impacting sensory quality.
Publications
- Soni, K. and Nannapaneni, R. 2010. Bacteriophage P100 significantly reduces Listeria monocytogenes on raw salmon fillet tissue. Journal of Food Protection 73:32-38.
- Soni, K., Nannapaneni, R. and Hagens, S. 2010. Reduction of Listeria monocytogenes on the surface of fresh channel catfish fillets by bacteriophage P100. Foodborne Pathogens and Disease 7:427-434.
- Soni, K. and Nannapaneni, R. 2010. Removal of Listeria monocytogenes biofilms with bacteriophage P100. Journal of Food Protection 73:1519-1524.
- Soni, K., Nannapaneni, R., Schilling, M.W. and Jackson, V. 2010. Bactericidal activity of GRAS lauric arginate against Listeria monocytogenes in milk and Queso fresco cheese. Journal of Dairy Science 93:4518-4525.
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Progress 01/01/09 to 12/31/09
Outputs
OUTPUTS: Ensuring the safety of aquaculture and seafood products from Listeria monocytogenes is a continuing challenge. To combat L. monocytogenes contamination of food products, food industries and regulatory agencies are continuously looking for novel and promising approaches that can prevent or decrease its occurrence or persistence. To meet this challenge, one promising approach is the use of a bacteriophage as an anti-listerial agent. Bacteriophage (phage) are viruses that infect bacterial cells specific for a target genus, serotype or a strain. All phages are obligate parasites since they solely rely on a specific host for propagation and in its absence they represent metabolically inert state. Phages are ubiquitous in nature, and it is estimated that earth harbors approximately 10 to the power of 31 phage particles and that as many as 10 to the power of 8 phage particles can be isolated from a 1 g of soil or water. Phages are naturally found in all food products. Recently, US Food and Drug Administration (FDA) approved a bacteriophage preparation, phage P100, as suitable to be included on both raw and ready-to-eat food products to combat L. monocytogenes contamination. Recent studies demonstrated that about 25 to 47% of fresh channel catfish fillets sampled from processing plants are contaminated with L. monocytogenes due to the inadequacy of current intervention strategies in these raw products. While there are no documented cases of listeriosis associated with the consumption of cooked catfish products, potential risks remain for the catfish products due to a high prevalence of L. monocytogenes. Currently, there are no reports on the effectiveness of phage P100 in killing L. monocytogenes on fresh catfish fillets and factors affecting its efficacy. We evaluate the use of the bacteriophage P100 against L. monocytogenes on catfish fillets. In this project, we demonstrated the effectiveness of phage P100 in reducing L. monocytogenes on fresh catfish fillet tissue as a function of: (i) Phage P100 contact time; (ii) Phage P100 dose; (iii) storage temperature; and (iv) storage duration. The results demonstrate that the P100 phage is an effective anti-listerial agent, yielding a significant one-time reduction in L. monocytogenes numbers in raw catfish fillets. Catfish processors may consider this new strategy to achieve low incidence of L. monocytogenes in raw catfish fillets. PARTICIPANTS: R. Nannapaneni, K. Soni, and S. Hagens This research has been conducted in collaboration with EBI Food Safety in Netherlands. This research provides valuable information to help catfish industry members in Mississippi as well as train graduate students so they are able to perform independent research. TARGET AUDIENCES: Catfish Processors in Mississippi, USDA-FSIS PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
The new 2008 farm bill legislation (PL 110-246) signed into law on June 18, 2008 extends United States Department of Agriculture Food Safety Inspection Service jurisdiction to include domestic and imported farmraised catfish. This legislation may lead to new federal regulations on microbiological requirements across aquaculture products based on risk analysis data. Host specific bacteriophages are candidates of continuing interest for food safety applications. Farmed freshwater fish is often inadvertently contaminated at low levels of L. monocytogenes. To date, only limited studies have been conducted on the usefulness of phages as L. monocytogenes biocontrol agents in raw and ready-to-eat food products. Our findings illustrate the effectiveness of lytic bacteriophage Listex P100 in reducing L. monocytogenes load from the surface of fresh catfish fillet. The fresh catfish fillet samples were surface inoculated with approximately 4.3 log10 colony forming units (CFU)/g of a two serotype mix (1/2a and 4b) of L. monocytogenes cells and then surface treated with phage P100. L. monocytogenes reduction was influenced by phage contact time and phage dose regardless of higher or lower temperature regimes tested on catfish fillet. The reduction in L. monocytogenes loads with the phage P100 dose of 2 x 10 to the power of 7 plaque forming units (PFU)/g was 1.4-2.0 log10 CFU/g at 4 degrees C, 1.7-2.1 log10 CFU/g at 10 degrees C, and 1.6-2.3 log10 CFU/g at room temperature (22 degrees C) on raw catfish fillet. The phage contact time of 30 min was adequate to yield greater than 1 log10 CFU/g reduction in L. monocytogenes, whereas 15 min contact time with phage yielded less than 1 log10 CFU/g reduction in L. monocytogenes loads on catfish fillet. Phage P100 titer was stable on catfish fillet samples and overall reductions in L. monocytogenes counts were still maintained over a 10-day shelf life at 4 degrees C or 10 degrees C by phage P100 treatment. Our findings demonstrates the efficacy of bacteriophage P100 for the quantitative reduction of L. monocytogenes on raw catfish fillet samples as influenced by phage dose, phage contact time and storage temperature. Since the psychrotrophic L. monocytogenes may grow slowly and increase during the refrigerated storage of catfish fillets, thus creating the food safety risk especially when there is a possibility of cross-contamination with ready-to-eat food products. Our results show that bacteriophage P100 can significantly reduce L. monocytogenes contamination on fresh catfish fillets (up to 1.5-2.3 log10 at P100 treatment levels of 5 x 10 to the power of 7 pfu per square cm). Thus, phage application can enhance food safety or possibly eliminate low-level presence of L. monocytogenes in catfish fillets.
Publications
- Soni, K. and Nannapaneni, R. 2009. Effect of contact time, dose, storage time and temperature on the efficacy of bacteriophage Listex P100 in reducing Listeria monocytogenes counts on the surface of fresh catfish fillet tissue. Poster # P3-73, International Association of Food Protection Annual Mtg., July 12-15, 2009, Grapevine, Texas.
- Soni, K., Hagens, S., and Nannapaneni, R. 2009. Listex. P100 significantly reduces Listeria monocytogenes on fresh channel catfish (Ictalurus punctatus). Euro Seafood and Processing Annual Mtg. 2009, Brussels, May 28-30.
- Soni, K., Nannapaneni, R., and Hagens, S. 2009. Reduction of Listeria monocytogenes on the surface of fresh channel catfish fillets by bacteriophage Listex P100. Foodborne Pathogens and Disease Annual Mtg. 2009, Dec 3. [Electronic publication ahead of print], http://www.liebertonline.com/doi/abs/10.1089/fpd.2009.0432prevSearch =allfield%253A%2528nannapane
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