U.S. flagAn official website of the United States government
                    Here's how you know **Official websites use .gov**
                            
                            A **.gov** website belongs to an official government organization in the United States.
 **Secure .gov websites use HTTPS**
                            
                            A **lock** (                            
                              A locked padlock                                                      
                            
                            ) or **https://** means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.


Menu Agricultural Research Service
						
                    U.S. DEPARTMENT OF AGRICULTURE
 close



Research
                Research Home
                            National Programs
                            Research Projects
                            Scientific Manuscripts
                            International Engagement
                            Scientific Software/Models
                            Databases and Datasets
                            Office of Scientific Quality Review
            Media
                News & Features
                            Multimedia
                            Briefing Room
                            Down on the Farm
                            Press Room
                            Science in Your Shopping Cart
                            Scientific Discoveries
                            Tellus
                            Under the Microscope
            About ARS
                About ARS Home
                            Staff Directory
                            Labs and Research Centers (Map)
                            Headquarter Offices
                            Organizational Chart
                            Employee Services (REE Employees Only)
                            Office of Outreach, Diversity, and Equal Opportunity
            Work With Us
                Work With Us Home
                            ARS Vacancies at USAJOBS
                            Careers at ARS Information
                            Scientific Collaborations
                            Extramural Agreements
                            1890 Faculty Research Sabbatical ProgramSearch small
                    Search
            
            ARS Home
                                About ARS
                                Contact Us




ARS Home Northeast Area Wyndmoor, Pennsylvania Eastern Regional Research Center Food Safety and Intervention Technologies Research Research Publications at this Location





- ARS National Programs
- Search for a scientific manuscript
- Search for a research project
- ARS Software
- Programs and Projects
- Collaborations
- Subjects of Investigation
- Publications

Title:   Author  item
                                            JORDAN, JOHARI - Delaware State Universityitem
                                            Gurtler, Joshuaitem
                                            MARKS, HARRY - Food Safety Inspection Service (FSIS)item
                                            Jones, Deanaitem
                                            SHAW, WILLIAM - Food Safety Inspection Service (FSIS)
  Submitted to: Food Microbiology
                                    Publication Type: Peer Reviewed Journal
                                    Publication Acceptance Date: 8/14/2010
                                    Publication  Date: 8/20/2010
                                    Citation: Jordan, J.S., Gurtler, J., Marks, H.M., Jones, D.R., Shaw, W.K. 2010. Inactivation kinetics of a four-strain composite of Salmonella Enteritidis and Oranienberg in commercial liquid egg yolk. Food Microbiology. 28:67-75.Interpretive Summary: The USDA requires that all liquid egg products be heat pasteurized for the destruction of the bacterium Salmonella prior to distribution to the public for consumption.  These guidelines were first established in 1970 and are currently being reviewed by the United States Department of Agriculture Food Safety and Inspection Service.  The goal of the present study was to determine the efficacy of thermal treatments to inactivate Salmonella in liquid egg yolk.  Four strains of Salmonella were grown and added to commercially-processed liquid egg yolk at a level of approximately ten million Salmonella cells per milliliter of yolk and thoroughly mixed.  This egg yolk was then placed in thin glass tubes, sealed, and heat treated at temperatures ranging from 58 to 66 deg C and cooled in ice water.  The level of Salmonella in the egg yolk was then determined by established microbiological sampling methods.  The data from these experiments were statistically analyzed and used to create a mathematical model that can be used to predict the reduction of Salmonella in liquid egg yolk pasteurized at temperatures ranging from 58 to 66 deg C. The results of this study provide information that can be used by liquid egg processing companies to aid in producing safe pasteurized egg yolk products and for satisfying pasteurization performance standards and industry guidance.
                                Technical Abstract: The goal of this study was to develop a general model of inactivation of salmonellae in commercial liquid egg yolk for temperatures ranging from 58 to 66 deg C by studying the inactivation kinetics of Salmonella in liquid egg yolk.  Heat-resistant salmonellae (three serovars of Enteritidis [two of phage type 8 and one PT 13] and one Oranienburg) were grown to stationary phase in Tryptic Soy Broth and concentrated ten-fold by centrifugation.  Each inoculum was added to liquid egg yolk and mixed thoroughly, resulting in a final population of ca. 7 log CFU/ml egg yolk.  Inoculated yolk was injected into sterile glass capillary tubes, flame-sealed and heated in a water bath at 58, 60, 62, 64, and 66 deg C.  Capillary tubes were ethanol sanitized, rinsed, and contents were extracted.  Yolk was diluted, surface plated onto Tryptic Soy Agar + 0.1% sodium pyruvate and 50 ug/ml nalidixic acid and incubated at 37 deg C for 24 h before colonies were enumerated. Decimal reduction values were calculated from survivor curves with a minimum inactivation of 6 log CFU/ml at each temperature.  Survival curves (except for 66 deg C) featured initial lag periods before first order linear inactivation. Estimated asymptotic D values were 1.83 min at 58 deg C, 0.69 min at 60 deg C, 0.26 min at 62 deg C, 0.096 min at 64 deg C and 0.036 min at 66 deg C.  The estimate of the z-value was ca. 4.7 deg C with standard error of 0.07 deg C.  A linear relationship between the log10 of the lag times and temperature was observed. A general kinetic model of inactivation was developed.  The results of the study provide information that can be used by processors to aid in producing safe pasteurized egg yolk product and for satisfying pasteurization performance standards and industry guidance.


Return to top


Connect with ARS Sign up


ARS Home
                            USDA.gov
                            Plain Writing
                            Policies & Links
                            Civil Rights Statements
                            FOIA
                            Accessibility Statement
                            Privacy Policy
                            Non-Discrimination Statement
                            Quality of Information
                            USA.gov
                            WhiteHouse.gov