{"id":{"repo_id":"vt","oai_identifier":"oai:vtechworks.lib.vt.edu:10919/135791"},"canonical_url":"https://search.dev.ndltd.org/etd/vt/oai:vtechworks.lib.vt.edu:10919/135791","repository":{"repo_id":"vt","name":"Virginia Tech","base_url":"https://vtechworks.lib.vt.edu/oai/request"},"display":{"title":"Evaluating the Persistence of Salmonella Tennessee and Lactobacillus brevis in Non-Alcoholic Beer under Low Pasteurization","abstract":"Foodborne pathogens such as Salmonella have been shown to survive in non-alcoholic (NA) beer (< 0.5 % ABV). Standard pasteurization recommendations for NA beer range from 80-120 pasteurization units (PU; 73.3 to 74.5°C for 1 min). However, producers may want to use lower pasteurization temperatures to preserve product quality. Recent studies show that pasteurization at lower temperatures may be effective at reducing spoilage organisms in traditional beer, but the impact on pathogens in NA beer is unknown. Additionally, spoilage organisms may impact Salmonella survival in NA beer, as spoilage organisms have been shown to impact pathogen survival. This study aimed to (i) evaluate the impact of a lower 0.75 PU thermal treatment on the survival of Salmonella enterica across six months in NA beer and (ii) to compare this survival when co-inoculated with Lactobacillus brevis. NA beer was brewed, filtered, and inoculated with Salmonella Tennessee (n = 360) and a subset was co-inoculated with L. brevis (n = 180) both at approximately 8.0 log CFU/mL. Three treatments were applied using a water bath: standard pasteurization (73.9°C for 1 min), low pasteurization (52°C for 1 min), and no pasteurization. Samples were stored at 14°C and enumerated in duplicate on tryptic soy agar and xylose lysine deoxycholate agar at 0, 1, 7, 14, 31, 59, 99, 129, 150, and 183 days, and co-inoculation samples were additionally inoculated on universal beer agar with 0.1% cycloheximide. PCR was used to confirm presumptive Salmonella positives. Data were analyzed using Kruskal-Wallis test and Dunn's test (p < 0.05). Significant differences were observed between pasteurization treatments post-pasteurization where Salmonella populations in the Salmonella only samples reduced by 8.07 ± 0.00, 2.25 ± 0.13, and 0.00 ± 0.00 log CFU/mL for the standard, low, and no pasteurization samples, respectively. Similarly post-pasteurization Salmonella populations in the co-inoculation samples reduced by 7.96 ± 0.00, 2.15 ± 0.83, and 0.00 ± 0.00 log CFU/mL for the standard, low, and no pasteurization samples, respectively. After 150 days, the no pasteurization and low pasteurization Salmonella only samples significantly differed as Salmonella populations reduced by 5.10 ± 0.32 in the no pasteurization samples and 4.03 ± 0.15 in the low pasteurization samples. There were no significant differences observed due to co-inoculation. Findings show that Salmonella can survive for at least 150 days in NA under low pasteurization conditions and can survive despite the presence of a common beer spoilage organism.","abstract_html":"Foodborne pathogens such as Salmonella have been shown to survive in non-alcoholic (NA) beer (&lt; 0.5 % ABV). Standard pasteurization recommendations for NA beer range from 80-120 pasteurization units (PU; 73.3 to 74.5°C for 1 min). However, producers may want to use lower pasteurization temperatures to preserve product quality. Recent studies show that pasteurization at lower temperatures may be effective at reducing spoilage organisms in traditional beer, but the impact on pathogens in NA beer is unknown. Additionally, spoilage organisms may impact Salmonella survival in NA beer, as spoilage organisms have been shown to impact pathogen survival. This study aimed to (i) evaluate the impact of a lower 0.75 PU thermal treatment on the survival of Salmonella enterica across six months in NA beer and (ii) to compare this survival when co-inoculated with Lactobacillus brevis. NA beer was brewed, filtered, and inoculated with Salmonella Tennessee (n = 360) and a subset was co-inoculated with L. brevis (n = 180) both at approximately 8.0 log CFU/mL. Three treatments were applied using a water bath: standard pasteurization (73.9°C for 1 min), low pasteurization (52°C for 1 min), and no pasteurization. Samples were stored at 14°C and enumerated in duplicate on tryptic soy agar and xylose lysine deoxycholate agar at 0, 1, 7, 14, 31, 59, 99, 129, 150, and 183 days, and co-inoculation samples were additionally inoculated on universal beer agar with 0.1% cycloheximide. PCR was used to confirm presumptive Salmonella positives. Data were analyzed using Kruskal-Wallis test and Dunn&#x27;s test (p &lt; 0.05). Significant differences were observed between pasteurization treatments post-pasteurization where Salmonella populations in the Salmonella only samples reduced by 8.07 ± 0.00, 2.25 ± 0.13, and 0.00 ± 0.00 log CFU/mL for the standard, low, and no pasteurization samples, respectively. Similarly post-pasteurization Salmonella populations in the co-inoculation samples reduced by 7.96 ± 0.00, 2.15 ± 0.83, and 0.00 ± 0.00 log CFU/mL for the standard, low, and no pasteurization samples, respectively. After 150 days, the no pasteurization and low pasteurization Salmonella only samples significantly differed as Salmonella populations reduced by 5.10 ± 0.32 in the no pasteurization samples and 4.03 ± 0.15 in the low pasteurization samples. There were no significant differences observed due to co-inoculation. Findings show that Salmonella can survive for at least 150 days in NA under low pasteurization conditions and can survive despite the presence of a common beer spoilage organism.","abstract_has_math":false,"creators":["Frierson, Maddyson Janet"],"institution":"Virginia Tech","degree_name":"Master of Science in Life Sciences","degree_level":"masters","degree_discipline":"Food Science and Technology","degree_department":"Food Science and Technology","school":null,"contributors":[],"advisors":[],"committee_chairs":["Hamilton, Alexis Marie"],"committee_members":["Hurley, Eldon Kenneth","Stewart, Amanda C."],"year":2025,"date_issued":"2025-07-08","date_published":"2025-07-08","updated_at":"2026-07-22T22:19:31Z","subjects":["Non-alcoholic Beer","Pasteurization","Salmonella","Lactobacillus brevis"],"languages":["en"],"rights":["In Copyright"],"rights_urls":["http://rightsstatements.org/vocab/InC/1.0/"],"identifier_entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["vt_gsexam:44352"],"render_values":[{"text":"vt_gsexam:44352","href":null,"code":true}]}]},"links":{"outbound_url":"https://hdl.handle.net/10919/135791","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.committeechair","label":"Committee Chair","values":["Hamilton, Alexis Marie"]},{"key":"dc:contributor.committeemember","label":"Committee Member","values":["Hurley, Eldon Kenneth","Stewart, Amanda C."]},{"key":"dc:contributor.department","label":"Department","values":["Food Science and Technology"]},{"key":"dc:creator","label":"Author","values":["Frierson, Maddyson Janet"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2025-07-09T08:00:20Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2025-07-09T08:00:20Z"]},{"key":"dc:date.issued","label":"Date","values":["2025-07-08"]},{"key":"dc:publisher","label":"Institution","values":["Virginia Tech"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Food Science and Technology"]},{"key":"thesis:degree_level","label":"Degree Level","values":["masters"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Master of Science in Life Sciences"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["Virginia Polytechnic Institute and State University"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Non-alcoholic Beer","Pasteurization","Salmonella","Lactobacillus brevis"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["In Copyright"]},{"key":"dc:rights.uri","label":"Rights URI","values":["http://rightsstatements.org/vocab/InC/1.0/"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["vt_gsexam:44352"]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://hdl.handle.net/10919/135791"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Foodborne pathogens such as Salmonella have been shown to survive in non-alcoholic (NA) beer (< 0.5 % ABV). Standard pasteurization recommendations for NA beer range from 80-120 pasteurization units (PU; 73.3 to 74.5°C for 1 min). However, producers may want to use lower pasteurization temperatures to preserve product quality. Recent studies show that pasteurization at lower temperatures may be effective at reducing spoilage organisms in traditional beer, but the impact on pathogens in NA beer is unknown. Additionally, spoilage organisms may impact Salmonella survival in NA beer, as spoilage organisms have been shown to impact pathogen survival. This study aimed to (i) evaluate the impact of a lower 0.75 PU thermal treatment on the survival of Salmonella enterica across six months in NA beer and (ii) to compare this survival when co-inoculated with Lactobacillus brevis. NA beer was brewed, filtered, and inoculated with Salmonella Tennessee (n = 360) and a subset was co-inoculated with L. brevis (n = 180) both at approximately 8.0 log CFU/mL. Three treatments were applied using a water bath: standard pasteurization (73.9°C for 1 min), low pasteurization (52°C for 1 min), and no pasteurization. Samples were stored at 14°C and enumerated in duplicate on tryptic soy agar and xylose lysine deoxycholate agar at 0, 1, 7, 14, 31, 59, 99, 129, 150, and 183 days, and co-inoculation samples were additionally inoculated on universal beer agar with 0.1% cycloheximide. PCR was used to confirm presumptive Salmonella positives. Data were analyzed using Kruskal-Wallis test and Dunn's test (p < 0.05). Significant differences were observed between pasteurization treatments post-pasteurization where Salmonella populations in the Salmonella only samples reduced by 8.07 ± 0.00, 2.25 ± 0.13, and 0.00 ± 0.00 log CFU/mL for the standard, low, and no pasteurization samples, respectively. Similarly post-pasteurization Salmonella populations in the co-inoculation samples reduced by 7.96 ± 0.00, 2.15 ± 0.83, and 0.00 ± 0.00 log CFU/mL for the standard, low, and no pasteurization samples, respectively. After 150 days, the no pasteurization and low pasteurization Salmonella only samples significantly differed as Salmonella populations reduced by 5.10 ± 0.32 in the no pasteurization samples and 4.03 ± 0.15 in the low pasteurization samples. There were no significant differences observed due to co-inoculation. Findings show that Salmonella can survive for at least 150 days in NA under low pasteurization conditions and can survive despite the presence of a common beer spoilage organism."]},{"key":"dc:description.abstractgeneral","label":"General Abstract","values":["Non-alcoholic (NA) beer has gained popularity in the United States, as sales have increased by about 30% in 2024, compared to 2023. Foodborne pathogens such as Salmonella have been shown to survive in NA beer for at least two months, and thus the lack of alcohol in these products may present unique food safety risks. Pasteurization has been proven to be an effective method to reduce foodborne pathogens in NA beer. Standard pasteurization recommendations for NA beer range from 80 to 120 pasteurization units (PU; 73.3 to 74.5°C for 1 min). However, producers may want to use lower pasteurization temperatures to preserve product quality (e.g., taste). Recent studies show that pasteurization at lower temperatures may effectively reduce spoilage organisms in traditional beer, but the impact on pathogens in NA beer is unknown. Additionally, spoilage organisms may impact Salmonella survival in NA beer. This study aimed to evaluate the impact of a lower pasteurization temperature on the survival of Salmonella across six months in NA beer and to compare this survival when co-inoculated with Lactobacillus brevis. NA beer was brewed, filtered, and inoculated with Salmonella Tennessee (n = 360), and a subset was co-inoculated with L. brevis (n = 180). Three pasteurization treatments were applied using a water bath: standard pasteurization (73.9°C for 1 min), low pasteurization (52°C for 1 min), and no pasteurization. Samples were stored at 14°C and counted in duplicate on non-selective (tryptic soy agar) and selective (xylose lysine deoxycholate) media from 0 to 183 days. Co-inoculation samples were additionally inoculated on universal beer agar with 0.1% cycloheximide. PCR was used to confirm presumptive Salmonella positives. The standard pasteurization treatment was the only treatment that effectively decreased Salmonella populations in NA beer to industry standards. No impact was observed from the spoilage organism. Additionally, Salmonella survived in the low pasteurization samples for at least 150 days. This study shows that standard pasteurization processes can effectively reduce food safety risks; however, the low pasteurization process will require additional hurdles to sufficiently reduce food safety risks for the NA beer industry."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["Master of Science in Life Sciences"]},{"key":"dc:format.medium","label":"Dc Format Medium","values":["ETD"]},{"key":"dc:title","label":"Title","values":["Evaluating the Persistence of Salmonella Tennessee and Lactobacillus brevis in Non-Alcoholic Beer under Low Pasteurization"]}]}],"canonical_facts":{"dc:contributor.committeechair":["Hamilton, Alexis Marie"],"dc:contributor.committeemember":["Hurley, Eldon Kenneth","Stewart, Amanda C."],"dc:contributor.department":["Food Science and Technology"],"dc:creator":["Frierson, Maddyson Janet"],"dc:date.accessioned":["2025-07-09T08:00:20Z"],"dc:date.available":["2025-07-09T08:00:20Z"],"dc:date.issued":["2025-07-08"],"dc:description.abstract":["Foodborne pathogens such as Salmonella have been shown to survive in non-alcoholic (NA) beer (< 0.5 % ABV). Standard pasteurization recommendations for NA beer range from 80-120 pasteurization units (PU; 73.3 to 74.5°C for 1 min). However, producers may want to use lower pasteurization temperatures to preserve product quality. Recent studies show that pasteurization at lower temperatures may be effective at reducing spoilage organisms in traditional beer, but the impact on pathogens in NA beer is unknown. Additionally, spoilage organisms may impact Salmonella survival in NA beer, as spoilage organisms have been shown to impact pathogen survival. This study aimed to (i) evaluate the impact of a lower 0.75 PU thermal treatment on the survival of Salmonella enterica across six months in NA beer and (ii) to compare this survival when co-inoculated with Lactobacillus brevis. NA beer was brewed, filtered, and inoculated with Salmonella Tennessee (n = 360) and a subset was co-inoculated with L. brevis (n = 180) both at approximately 8.0 log CFU/mL. Three treatments were applied using a water bath: standard pasteurization (73.9°C for 1 min), low pasteurization (52°C for 1 min), and no pasteurization. Samples were stored at 14°C and enumerated in duplicate on tryptic soy agar and xylose lysine deoxycholate agar at 0, 1, 7, 14, 31, 59, 99, 129, 150, and 183 days, and co-inoculation samples were additionally inoculated on universal beer agar with 0.1% cycloheximide. PCR was used to confirm presumptive Salmonella positives. Data were analyzed using Kruskal-Wallis test and Dunn's test (p < 0.05). Significant differences were observed between pasteurization treatments post-pasteurization where Salmonella populations in the Salmonella only samples reduced by 8.07 ± 0.00, 2.25 ± 0.13, and 0.00 ± 0.00 log CFU/mL for the standard, low, and no pasteurization samples, respectively. Similarly post-pasteurization Salmonella populations in the co-inoculation samples reduced by 7.96 ± 0.00, 2.15 ± 0.83, and 0.00 ± 0.00 log CFU/mL for the standard, low, and no pasteurization samples, respectively. After 150 days, the no pasteurization and low pasteurization Salmonella only samples significantly differed as Salmonella populations reduced by 5.10 ± 0.32 in the no pasteurization samples and 4.03 ± 0.15 in the low pasteurization samples. There were no significant differences observed due to co-inoculation. Findings show that Salmonella can survive for at least 150 days in NA under low pasteurization conditions and can survive despite the presence of a common beer spoilage organism."],"dc:description.abstractgeneral":["Non-alcoholic (NA) beer has gained popularity in the United States, as sales have increased by about 30% in 2024, compared to 2023. Foodborne pathogens such as Salmonella have been shown to survive in NA beer for at least two months, and thus the lack of alcohol in these products may present unique food safety risks. Pasteurization has been proven to be an effective method to reduce foodborne pathogens in NA beer. Standard pasteurization recommendations for NA beer range from 80 to 120 pasteurization units (PU; 73.3 to 74.5°C for 1 min). However, producers may want to use lower pasteurization temperatures to preserve product quality (e.g., taste). Recent studies show that pasteurization at lower temperatures may effectively reduce spoilage organisms in traditional beer, but the impact on pathogens in NA beer is unknown. Additionally, spoilage organisms may impact Salmonella survival in NA beer. This study aimed to evaluate the impact of a lower pasteurization temperature on the survival of Salmonella across six months in NA beer and to compare this survival when co-inoculated with Lactobacillus brevis. NA beer was brewed, filtered, and inoculated with Salmonella Tennessee (n = 360), and a subset was co-inoculated with L. brevis (n = 180). Three pasteurization treatments were applied using a water bath: standard pasteurization (73.9°C for 1 min), low pasteurization (52°C for 1 min), and no pasteurization. Samples were stored at 14°C and counted in duplicate on non-selective (tryptic soy agar) and selective (xylose lysine deoxycholate) media from 0 to 183 days. Co-inoculation samples were additionally inoculated on universal beer agar with 0.1% cycloheximide. PCR was used to confirm presumptive Salmonella positives. The standard pasteurization treatment was the only treatment that effectively decreased Salmonella populations in NA beer to industry standards. No impact was observed from the spoilage organism. Additionally, Salmonella survived in the low pasteurization samples for at least 150 days. This study shows that standard pasteurization processes can effectively reduce food safety risks; however, the low pasteurization process will require additional hurdles to sufficiently reduce food safety risks for the NA beer industry."],"dc:description.degree":["Master of Science in Life Sciences"],"dc:format.medium":["ETD"],"dc:identifier.other":["vt_gsexam:44352"],"dc:identifier.uri":["https://hdl.handle.net/10919/135791"],"dc:language.iso":["en"],"dc:publisher":["Virginia Tech"],"dc:rights":["In Copyright"],"dc:rights.uri":["http://rightsstatements.org/vocab/InC/1.0/"],"dc:subject":["Non-alcoholic Beer","Pasteurization","Salmonella","Lactobacillus brevis"],"dc:title":["Evaluating the Persistence of Salmonella Tennessee and Lactobacillus brevis in Non-Alcoholic Beer under Low Pasteurization"],"dc:type":["Thesis"],"thesis:degree_discipline":["Food Science and Technology"],"thesis:degree_level":["masters"],"thesis:degree_name":["Master of Science in Life Sciences"],"thesis:institution_name":["Virginia Polytechnic Institute and State University"]},"updated_at":"2026-07-22T22:19:31Z"}