About

Lynette Johnston is an Assistant Professor and Food Safety Extension Specialist at North Carolina State University, working within the Food, Bioprocessing and Nutrition Sciences department. Her extension and outreach activities focus on working with North Carolina food processors and fresh produce growers to reduce microbial risks through comprehensive education and extension programs, with a particular emphasis on the implementation of FSMA regulations. She is involved in extension activities related to preventive controls for human food, produce safety, foreign supplier verification programs, good manufacturing practices, sanitation, allergen management, and environmental monitoring programs. Dr. Johnston teaches courses such as Food Microbiology (FS 405/505) and actively participates in professional memberships, including serving as chair-elect of the NC Food Safety and Defense Task Force and as a member of the NC Fresh Produce Task Force's executive committee. She holds a Ph.D. in Food Science from North Carolina State University (2005) and a B.S. in Food Science with Honors I from Texas Tech University (1998). Her research and extension efforts are dedicated to enhancing food safety practices among food processors and produce growers, with a focus on microbial risk reduction and regulatory compliance.

Research topics

• Computer Science
• Medicine
• Chemistry
• Business
• Biochemistry
• Library science
• Geography
• Chromatography
• Medical education
• Food science

Selected publications

• Southern Region Produce Safety Alliance Grower Training: Using Pre- and Post-Training Knowledge Assessments to Understand Training Effectiveness

  Journal of Food Protection · 2024 · 4 citations

  • Business
  • Medical education
  • Geography

  The Produce Safety Alliance (PSA) grower training was introduced in 2016 as the standardized curriculum to meet the training requirements of the Food and Drug Administration's (FDA) Food Safety Modernization Act's (FSMA) Produce Safety Rule (PSR). The PSR states that at least one supervisor or responsible party from each farm must have successfully completed this food safety training or one equivalent to the standardized curriculum, as recognized by the FDA. This study evaluated the effectiveness of PSA trainings conducted between 2017 and 2019 in the Southern United States by the Southern Regional Center for Food Safety Training, Outreach, and Technical Assistance by analyzing pre- and posttest assessments. Effectiveness was based on a 25-question knowledge assessment administered to participants before (n = 2494) and after (n = 2460) each training. The knowledge assessment indicated the overall effectiveness of the training, with average scores increasing significantly from pretest (15.9/25, 63.4%) to posttest (20.3/25, 81.3%) (P < 0.001). The greatest knowledge gains were seen in the Postharvest Handling and Sanitation, How to Develop a Farm Food Safety Plan, and Agricultural Water modules. Notably, these modules had lower posttest scores compared to the other modules, indicating that the amount of knowledge gained did not necessarily correspond with a sufficient understanding of the material. To ensure that participants understand all aspects of the PSR and best practices to minimize food safety risks, additional or advanced trainings may be needed. Additionally, the current testing instrument (pre-/posttest) used for PSA grower training, while validated, may not be optimal, thus alternative methods to assess the training effectiveness are likely needed.

  PublisherDOI

• List of contributors

  Elsevier eBooks · 2023

  • Computer Science
  • Library science
  • Computer Science
  PublisherDOI

• IngredientDB: A GUI-based Matlab database program for estimating the pH of acid or acidified food formulations from buffer capacity models

  SoftwareX · 2023-10-13 · 2 citations

  articleOpen accessSenior author

  A Matlab GUI program, IngredientDB, was developed to help determine the pH and buffering of ingredients in acidic food products based on product formulations. A database of buffer capacity models for both low acid and acid food ingredients was developed and used to show how individual food ingredients influence the final product pH. The IngredientDB program may be used for in silico formulations of acidic food products to help assure the quality and safety of these foods.

  PublisherOA PDFDOI

• IngredientDB: a GUI-based Matlab database program for estimating the pH of acid or acidified food formulations from buffer capacity models

  SSRN Electronic Journal · 2023-01-01

  preprintOpen accessSenior author
  PublisherDOI

• Modeling the formulation pH of elderberry syrup with multiple weak acids

  Journal of Food Science · 2023 · 4 citations

  • Chemistry
  • Food science
  • Chromatography

  The objective of this work was to develop methods to assess the influence of the ingredients of an acidified elderberry syrup on product pH. A measure of total ingredient buffering (tBeta) was defined as the area under the buffer capacity curve of a food mixture or ingredient for pH 2-12. Citric acid (1% w/v), elderberry juice (75% v/v), and malic acid (0.75% w/v) had greater buffering (tBeta values of 15.33, 12.00, and 10.95, respectively) than ascorbic acid (0.75%) or lemon juice (3% v/v) (tBeta of 5.74 and 3.30, respectively). All other ingredients, including added spices (≤1% each) and honey (25% w/v), had tBeta values <2. The observed pH for the syrup mixture (pH 2.67) was within 0.11 pH units of the predicted pH based on combined buffer models of the acid and low acid ingredients (pH 2.78) using Matlab software. A total of 16 model syrup formulations containing elderberry juice with mixed acids (malic, acetic, and ascorbic) and having pH values between 3 and 4 were prepared. The pH values of the formulations were compared to predicted values from combined buffer models of the individual ingredients. Regression analysis indicated an excellent fit of the observed and predicted pH data, with a root mean square error of 0.076 pH units. The results indicated that buffer models may be useful for in silico estimates of how the ingredients in acid and acidified foods may influence pH, thus aiding in product development and safety assessments. PRACTICAL APPLICATION: Buffer models using recently developed titration methods for individual acid and low-acid food ingredients can be used to estimate the pH of formulations of these ingredients in silico. The total buffering (tBeta) for ingredients or mixtures, along with ingredient concentrations, may be a useful metric for helping to determine which ingredients will have the greatest impact on pH. Such models can aid product development efforts and safety assessments.

  PublisherOA PDFDOI

• Salmonella and tomatoes

  Elsevier eBooks · 2023-01-01 · 1 citations

  book-chapter1st authorCorresponding
  PublisherDOI

• Leadership and governance in Australian agriculture: the determinants of board membership in representative, statutory and corporate organizations in Australian agriculture

  UWA Profiles and Research Repository (UWA) · 2018-01-01 · 1 citations

  articleOpen access1st authorCorresponding
  PublisherOA PDFDOI

• Microbial Load of Fresh Produce and Paired Equipment Surfaces in Packing Facilities Near the U.S. and Mexico Border

  Journal of Food Protection · 2017-03-08 · 15 citations

  article
  PublisherDOI

• Development and Evaluation of a Multi‐Institutional Case Studies‐Based Course in Food Safety

  Journal of Food Science Education · 2015-06-22 · 3 citations

  articleOpen access

  Abstract Developing novel, engaging courses in food safety is necessary to train professionals in this discipline. Courses that are interactive and case‐based encourage development of critical thinking skills necessary for identifying and preventing foodborne disease outbreaks. The purpose of this study was to assess the efficacy of a case study module‐based course for upper division undergraduate and graduate students interested in food safety. Four independent case study modules were developed and implemented by 4 universities working in tandem over a semester course. All case studies incorporated molecular and epidemiological methods employed by professionals in food safety in outbreak investigations. Each case study was based on a (i) suspect foodborne pathogen, (ii) identification tools including biochemical test variations and pulsed field gel electrophoresis, multiplex PCR and/or whole genome sequencing, and (iii) suspect location and company type from farm to production site to restaurant. Pre‐ and postinstruction evaluations revealed significant increases in understanding of the concepts introduced through each module as demonstrated by overall mean normalized gain of 0.32 ± 0.35 (15% ± 19%; n = 60). Institution, role of instructor, prescore, and learning environment all played a significant role in the effects of overall learning. This study provides a successful model for a case study‐based course in food safety. The guidelines and materials developed by our group are available for use by other institutions.

  PublisherOA PDFDOI

• Associations between Weather and Microbial Load on Fresh Produce Prior to Harvest

  Journal of Food Protection · 2015-03-31 · 20 citations

  article
  PublisherDOI

Frequent coauthors

• M. Mitsu Suyemoto

  North Carolina State University

  9 shared

• Craig Altier

  9 shared

• Hao Fang

  Eastern Hepatobiliary Surgery Hospital

  9 shared

• Na Lin

  Qufu Normal University

  9 shared

• Siming Wang

  Chinese Academy of Medical Sciences & Peking Union Medical College

  9 shared

• Qian Wang

  Shanghai Medical College of Fudan University

  9 shared

• Binghe Wang

  Chengdu University of Technology

  9 shared

• Jun Yan

  Princeton University

  9 shared

Education

• Ph.D., Food Science

  University of California, Davis

  1995

• M.S., Food Science

  University of California, Davis

  1991

• B.S., Food Science

  University of California, Davis

  1988

Awards & honors

• NC Food Safety and Defense Task Force (chair-elect)
• NC Fresh Produce Task Force (Executive committee)
• International Association for Food Protection