Inactivation of Yersinia pseudotuberculosis 197 and Francisella tularensis LVS in Beverages by High Pressure Processing

• Published in: Journal of food protection Vol. 72; no. 1; pp. 165 - 168
• Main Authors: Schlesser, Joseph E, Parisi, Brian
• Format: Journal Article
• Language: English
• Published: Des Moines, IA International Association for Food Protection 2009; Elsevier Limited
• Subjects: Acids; animal pathogenic bacteria; Animals; Beverages; Beverages - microbiology; Biological and medical sciences; biological resistance; biosecurity; bioterrorism; Citrus sinensis - microbiology; Colony Count, Microbial; Consumer Product Safety; Food; Food Contamination - analysis; Food Contamination - prevention & control; Food Handling - methods; Food industries; Food microbiology; food processing; Food safety; Food supply; Foodborne diseases; Francisella tularensis; Francisella tularensis - growth & development; Fruit juices; Fundamental and applied biological sciences. Psychology; High pressure; high pressure treatment; High temperature; Humans; Hydrostatic Pressure; Inactivation; Microorganisms; Milk; Milk - microbiology; orange juice; Pasteurization; plate count; Polyesters; Salmonella; skim milk; Temperature; Terrorism; Time Factors; Vaccines; Yersinia pseudotuberculosis; Yersinia pseudotuberculosis - growth & development; Physical dressing; Bacteria; Beverage; Inactivation; Enterobacteriaceae; High pressure; Yersinia pseudotuberculosis
• ISSN: 0362-028X; 1944-9097
• DOI: 10.4315/0362-028X-72.1.165

In 2003, the U.S. Department of Health and Human Services announced a new research program to develop technologies and strategies to prevent and minimize potential food safety and security threats. The threat of terrorist attacks against the nation's food supplies has created the need to study microorganisms not typically associated with foodborne illness. High-pressure processing has been proposed as a treatment to reduce Yersinia pestis and Francisella tularensis LVS levels in beverages. The objectives of this work were to determine the pressure resistance of Y. pseudotuberculosis 197 (surrogate for Y. pestis) and F. tularensis LVS (vaccine strain). For each bacterium, samples of ultrahigh-temperature pasteurized skim milk and pasteurized reduced-acid orange juice (pH ca. 4.2) were inoculated at a minimum level of 5 log CFU/ml. Ten-milliliter samples of the inoculated product were vacuum sealed in polyester pouches and subjected to pressures of 300 and 500 MPa for holding times ranging from 30 s to 6 min. One set of trials was performed at an initial temperature of 10°C and another at 25°C. Processed samples were immediately plated and enumerated. A pressure treatment of 300 MPa at 25°C for less than 6 min was not sufficient to achieve a 5-log reduction of Y. pseudotuberculosis 197 or F. tularensis LVS in milk. However, a pressure treatment of 500 MPa was effective at hold times as low as 30 s. Overall, F. tularensis LVS demonstrated less pressure resistance than Y. pseudotuberculosis 197. Based on these findings, a high-pressure process designed to inactivate 5 log CFU of Y. pseudotuberculosis 197 per ml and F. tularensis LVS in orange juice or milk should be set at or above 500 MPa with a hold time of 2 min or greater.