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Baseline study for prevalence of resistant and susceptible campylobacter in retail ground beef
164
Abstracts
Meat and Poultry Safety
Meat and Poultry Safety
121 Thermal inactivation of salmonella in high-fat frankfurters R. Mcminna,⁎, J.J. Sindelara, K.A. Glassb, R. Hansonc, aUniversity of Wisconsin – Madison, bFood Research Institute, Madison, cHansonTech, Hudson, United States
124 Baseline study for prevalence of resistant and susceptible campylobacter in retail ground beef K.A. Ortega⁎, G.H. Loneragan, P.M. Ortega, L.S. Guillen, J.L. Vipham, J.C. Brooks, M.M. Brashears, Animal and Food Sciences, Texas Tech University, Lubbock, United States
Objectives: USDA, FSIS Appendix A is widely used as validation support for thermal processes, but its time-temperature tables and humidity requirements were originally developed and validated only for Salmonella in roast, cooked, and corned beef. Appendix A however, is routinely applied to a much wider array of products than those examined in the original study. Furthermore the humidity requirements are limited in scope and difficult to apply to certain processes. Product-specific, time-temperature tables along with more flexible and robust humidity requirements are needed to improve validation of thermal processes Purpose: To determine the temperature-death times of Salmonella in high-fat frankfurter batter at four different temperatures and validate these findings using commercial product and cooking processes. Materials and methods: Mechanically-separated turkey, 50% lean pork trimmings, and all non-meat ingredients were chopped in a vertical cutter mixer, under vacuum, until a temperature of 12.7 °C was reached. The batter was then inoculated with 8-log cfu/g Salmonella (5-strain mixture) and mixed for 1.5 minutes. D-value determination: One-g samples of inoculated batter were flattened into a thin film (0.5-1.0 mm thickness) in moistureimpermeable pouches and vacuum-packaged. Samples were heated at one of four temperatures (54.4 °C, 60 °C, 65.6 °C, 71.1 °C) in a water bath. Triplicate samples were removed at predetermined time points and immediately chilled to ≤4 °C by immersion in an ice water bath. Samples were then enumerated for the survival of Salmonella using XLD agar with a thin layer overlay of nonselective media to enhance recovery of injured cells. D-values were calculated from the linear regression on log reduction of Salmonella versus time. This experiment was replicated three times. Validation: Inoculated batter was stuffed into size 28 cellulose casings and linked manually in 6-inch increments. Links were then transferred to a combination steam/convection oven and thermally processed following one of two cook schedules until an internal temperature of 71.1 °C was achieved. The control cycle maintained a relative humidity ≥50% for half the duration of the cook cycle. The test cycle only applied steam during the final step of the process to investigate the efficacy of a surface lethality step. For both processes, triplicate links were removed when product internal temperature reached 54.4 °C, 62.7 °C, and 71.1 °C. Casings were removed aseptically and 2.5 cm was removed from each end of the links. The central portion of each link was enumerated for the survival of Salmonella using the methods described above. This experiment was repeated twice. Results: D-values for 54.4 °C, 60 °C, 65.6 °C, and 71.1 °C were 20.48 ± 6.54, 1.74 ± 0.10, 0.26 ± 0.06, and 0.06 ± 0.01 minutes, respectively. The control cycle produced an average log reduction of -0.01 ± 0.04, 6.86 ± 0.11, and 6.86 ± 0.11 for the 54.4 °C, 62.7 °C, and 71.1 °C target temperatures, respectively. The test cycle achieved an average log reduction of 0.07 ± 0.11, 5.94 ± 1.30, and 6.91 ± 0.18 for the 54.4 °C, 62.7 °C, and 71.1 °C target temperatures, respectively. The test cycle achieved lethality comparable to that seen with the control cycle. Conclusion: Appendix A time-temperature recommendations are adequate for controlling Salmonella in high-fat, small diameter products. Wet-bulb time-temperature may be sufficient as a replacement for relative humidity requirements. Keywords: food safety, Salmonella, thermal processing, validation doi:10.1016/j.meatsci.2015.08.140
Objectives: The objective of this study was to determine the prevalence of resistant and susceptible Campylobacter spp. across various protein to fat ratios and packaging types of ground beef during the spring in retail markets in Lubbock, Texas. Materials and methods: During the spring of 2013, a total of 178 ground beef samples were collected from seven stores in Lubbock, Texas. Samples were processed and subjected to detection of Campylobacter using a commercially available PCR-based system. Positive samples were confirmed by plating samples onto Modified Charcoal Cefoperazone Deoxycholate Agar and R&F® Campylobacter chromogenic plating media as well as with Schimdex Campy agglutination. A total of 162 isolates were selected and frozen at -80C until further use. Isolates were resuscitated on blood agar and subjected to National Antimicrobial Resistance Monitoring System (NARMS) testing methods to determine resistance patterns. Resistant profiles were determined using the SWIN software system with clinical breakpoints. A multiple sample proportions test was performed in R to determine differences in prevalence of resistant Campylobacter isolates to the four antibiotics across package type and fat content. Results: An overall prevalence of 30.5% (n = 54) of 178 raw ground beef samples was observed. A total of 162 isolates from 54 positive samples were selected, and 54.3% (n = 88) were successfully recovered from frozen stocks. According to the results determined using the SWIN software, there were four out of the nine antibiotics (erythromycin, gentamicin, ciprofloxacin, and tetracycline) with results for susceptibility or resistance. Campylobacter isolates expressed resistance to specific antibiotics as follows: 4.54% (n = 4) for ciprofloxacin, 91.9% (n = 68) for erythromycin, 15.3% (n = 13) for gentamicin, and 4.60% (n = 4) tetracycline. There was a significant difference (P b 0.05) in the prevalence of resistant Campylobacter observed among the four antibiotics. Only 3.41% (n = 3) of the isolates were multidrug resistant as defined by the isolate exhibiting resistance to three or more classes of antibiotics. Campylobacter isolates expressed resistance based on packaging type as follows: 52.0% (n = 64) for overwrap, 27.8% (n = 10) for chub, and 33.3% (n = 1) for over-the-counter packaging (P = 0.03). The resistance of Campylobacter isolates varied across protein to fat ratios as follows: 61.9% (n = 13) for 73:27, 47.2% (n = 34) for 85:15, 6.67 (n = 1) for 80:20, 100% (n = 12) for 90:10, 77.8% (n = 21) for 93:7, and 46.7% (n = 7) for 96:4 (P b 0.05). Conclusion: A high prevalence of resistant Campylobacter was observed in raw ground beef in this study. Prevalence of antibiotic resistant Campylobacter varied greatly among both package type and fat content.
Keywords: Antibiotic resistant, Campylobacter, Ground beef doi:10.1016/j.meatsci.2015.08.141
Meat and Poultry Safety 125 Comparison of conventional culture methods with multiplex real-time PCR for salmonella spp. detection in fecal and hide samples from small ruminants S.G. Sandersa,⁎, K.W. Bradena, K.E. Hanlonb, M.M. Brashearsb, L.A. Branhama, aDepartment of Agriculture, Angelo State University, San
Abstracts
Meat and Poultry Safety
Meat and Poultry Safety
121 Thermal inactivation of salmonella in high-fat frankfurters R. Mcminna,⁎, J.J. Sindelara, K.A. Glassb, R. Hansonc, aUniversity of Wisconsin – Madison, bFood Research Institute, Madison, cHansonTech, Hudson, United States
124 Baseline study for prevalence of resistant and susceptible campylobacter in retail ground beef K.A. Ortega⁎, G.H. Loneragan, P.M. Ortega, L.S. Guillen, J.L. Vipham, J.C. Brooks, M.M. Brashears, Animal and Food Sciences, Texas Tech University, Lubbock, United States
Objectives: USDA, FSIS Appendix A is widely used as validation support for thermal processes, but its time-temperature tables and humidity requirements were originally developed and validated only for Salmonella in roast, cooked, and corned beef. Appendix A however, is routinely applied to a much wider array of products than those examined in the original study. Furthermore the humidity requirements are limited in scope and difficult to apply to certain processes. Product-specific, time-temperature tables along with more flexible and robust humidity requirements are needed to improve validation of thermal processes Purpose: To determine the temperature-death times of Salmonella in high-fat frankfurter batter at four different temperatures and validate these findings using commercial product and cooking processes. Materials and methods: Mechanically-separated turkey, 50% lean pork trimmings, and all non-meat ingredients were chopped in a vertical cutter mixer, under vacuum, until a temperature of 12.7 °C was reached. The batter was then inoculated with 8-log cfu/g Salmonella (5-strain mixture) and mixed for 1.5 minutes. D-value determination: One-g samples of inoculated batter were flattened into a thin film (0.5-1.0 mm thickness) in moistureimpermeable pouches and vacuum-packaged. Samples were heated at one of four temperatures (54.4 °C, 60 °C, 65.6 °C, 71.1 °C) in a water bath. Triplicate samples were removed at predetermined time points and immediately chilled to ≤4 °C by immersion in an ice water bath. Samples were then enumerated for the survival of Salmonella using XLD agar with a thin layer overlay of nonselective media to enhance recovery of injured cells. D-values were calculated from the linear regression on log reduction of Salmonella versus time. This experiment was replicated three times. Validation: Inoculated batter was stuffed into size 28 cellulose casings and linked manually in 6-inch increments. Links were then transferred to a combination steam/convection oven and thermally processed following one of two cook schedules until an internal temperature of 71.1 °C was achieved. The control cycle maintained a relative humidity ≥50% for half the duration of the cook cycle. The test cycle only applied steam during the final step of the process to investigate the efficacy of a surface lethality step. For both processes, triplicate links were removed when product internal temperature reached 54.4 °C, 62.7 °C, and 71.1 °C. Casings were removed aseptically and 2.5 cm was removed from each end of the links. The central portion of each link was enumerated for the survival of Salmonella using the methods described above. This experiment was repeated twice. Results: D-values for 54.4 °C, 60 °C, 65.6 °C, and 71.1 °C were 20.48 ± 6.54, 1.74 ± 0.10, 0.26 ± 0.06, and 0.06 ± 0.01 minutes, respectively. The control cycle produced an average log reduction of -0.01 ± 0.04, 6.86 ± 0.11, and 6.86 ± 0.11 for the 54.4 °C, 62.7 °C, and 71.1 °C target temperatures, respectively. The test cycle achieved an average log reduction of 0.07 ± 0.11, 5.94 ± 1.30, and 6.91 ± 0.18 for the 54.4 °C, 62.7 °C, and 71.1 °C target temperatures, respectively. The test cycle achieved lethality comparable to that seen with the control cycle. Conclusion: Appendix A time-temperature recommendations are adequate for controlling Salmonella in high-fat, small diameter products. Wet-bulb time-temperature may be sufficient as a replacement for relative humidity requirements. Keywords: food safety, Salmonella, thermal processing, validation doi:10.1016/j.meatsci.2015.08.140
Objectives: The objective of this study was to determine the prevalence of resistant and susceptible Campylobacter spp. across various protein to fat ratios and packaging types of ground beef during the spring in retail markets in Lubbock, Texas. Materials and methods: During the spring of 2013, a total of 178 ground beef samples were collected from seven stores in Lubbock, Texas. Samples were processed and subjected to detection of Campylobacter using a commercially available PCR-based system. Positive samples were confirmed by plating samples onto Modified Charcoal Cefoperazone Deoxycholate Agar and R&F® Campylobacter chromogenic plating media as well as with Schimdex Campy agglutination. A total of 162 isolates were selected and frozen at -80C until further use. Isolates were resuscitated on blood agar and subjected to National Antimicrobial Resistance Monitoring System (NARMS) testing methods to determine resistance patterns. Resistant profiles were determined using the SWIN software system with clinical breakpoints. A multiple sample proportions test was performed in R to determine differences in prevalence of resistant Campylobacter isolates to the four antibiotics across package type and fat content. Results: An overall prevalence of 30.5% (n = 54) of 178 raw ground beef samples was observed. A total of 162 isolates from 54 positive samples were selected, and 54.3% (n = 88) were successfully recovered from frozen stocks. According to the results determined using the SWIN software, there were four out of the nine antibiotics (erythromycin, gentamicin, ciprofloxacin, and tetracycline) with results for susceptibility or resistance. Campylobacter isolates expressed resistance to specific antibiotics as follows: 4.54% (n = 4) for ciprofloxacin, 91.9% (n = 68) for erythromycin, 15.3% (n = 13) for gentamicin, and 4.60% (n = 4) tetracycline. There was a significant difference (P b 0.05) in the prevalence of resistant Campylobacter observed among the four antibiotics. Only 3.41% (n = 3) of the isolates were multidrug resistant as defined by the isolate exhibiting resistance to three or more classes of antibiotics. Campylobacter isolates expressed resistance based on packaging type as follows: 52.0% (n = 64) for overwrap, 27.8% (n = 10) for chub, and 33.3% (n = 1) for over-the-counter packaging (P = 0.03). The resistance of Campylobacter isolates varied across protein to fat ratios as follows: 61.9% (n = 13) for 73:27, 47.2% (n = 34) for 85:15, 6.67 (n = 1) for 80:20, 100% (n = 12) for 90:10, 77.8% (n = 21) for 93:7, and 46.7% (n = 7) for 96:4 (P b 0.05). Conclusion: A high prevalence of resistant Campylobacter was observed in raw ground beef in this study. Prevalence of antibiotic resistant Campylobacter varied greatly among both package type and fat content.
Keywords: Antibiotic resistant, Campylobacter, Ground beef doi:10.1016/j.meatsci.2015.08.141
Meat and Poultry Safety 125 Comparison of conventional culture methods with multiplex real-time PCR for salmonella spp. detection in fecal and hide samples from small ruminants S.G. Sandersa,⁎, K.W. Bradena, K.E. Hanlonb, M.M. Brashearsb, L.A. Branhama, aDepartment of Agriculture, Angelo State University, San