About

Elizabeth A. Bihn is a Senior Extension Associate in the Department of Food Science at Cornell University and serves as the director of the Produce Safety Alliance and the National Good Agricultural Practices (GAPs) Program. Her research primarily focuses on irrigation water quality used during fruit and vegetable production. Her extension program aims to reduce microbial risks to fresh fruits and vegetables by developing engaging and effective educational materials through collaboration with growers, farm workers, produce industry personnel, students, teachers, and consumers. Elizabeth Bihn holds a B.S. from Ohio State University in zoology, an M.S. from the University of Florida in horticulture, and a Ph.D. from Cornell University in food science.

Research topics

• Medicine
• Biology
• Biotechnology
• Food science
• Environmental science
• Risk analysis (engineering)
• Economics
• Intensive care medicine
• Agricultural science
• Agronomy
• Nursing
• Environmental health
• Toxicology
• Marketing
• Engineering
• Veterinary medicine
• Business
• Accounting
• Agricultural economics
• Virology

Selected publications

• Motivations and Barriers to Implementing Produce Food Safety Practices

  Journal of Food Protection · 2025-06-18 · 6 citations

  articleOpen accessSenior author

  This study utilizes a unique set of primary data collected from produce growers who sell to U.S. markets. The research assesses the implementation of on-farm produce safety practices, identifies the biggest challenges faced by growers to date, and explores barriers to further adoption of new practices. The majority of survey respondents reported implementing produce safety practices on their farms. Key challenges identified include recordkeeping, wildlife and domesticated animals, worker health and hygiene training, and job-specific produce safety worker training. Motivators for adopting produce safety practices include regulatory compliance, personal commitment to produce safety, maintaining market access, and reducing liability. Time and financial constraints were the most commonly reported barriers across all food safety practices, with the impact varying depending on the specific practice. The findings highlight the importance of outreach and support for growers who continue to face difficulties in implementing produce safety practices. Providing evidence-based education that simplifies the adoption of risk-reducing tools and techniques supports enhancing produce safety and public health. Additionally, targeted research focusing on vulnerabilities, behavioral change factors, and cost-effective mitigation strategies can assist growers in effectively identifying risks and implementing safety practices.

  PublisherDOI

• Produce safety alliance grower training knowledge assessment results

  Advancements in Agricultural Development · 2024-04-16 · 1 citations

  articleOpen access

  The Produce Safety Alliance (PSA) Grower Training (GT) curriculum was developed to provide produce growers with training that meets requirements in §112.22(c) of the Food Safety Modernization Act (FSMA) Produce Safety Rule (PSR). Four regional food safety centers evaluated course attendees’ knowledge change over four years (2019 to 2022) using a pre- and post-test quiz. Knowledge assessment results showed (a) respondents gained knowledge on each of the seven modules presented in the curriculum; (b) the curriculum content had a large effect on knowledge gain; (c) knowledge gain differed significantly between years, but the differences were not of practical importance; (d) remote participants learned significantly more than in-person participants, but differences were not of practical importance; and (e) the quiz consisted of low and moderate difficulty questions (no questions were high difficulty) and had generally acceptable discriminant properties. Implementation of the FSMA PSR has progressed from an educational to a regulatory phase, and the authors recommend replacing the knowledge assessment with a tool that measures how the PSA course prepares growers for compliance.

  PublisherOA PDFDOI

• The role of Good Agricultural Practices (GAPs) in preventing pathogenic microbial contamination of fresh produce

  Burleigh Dodds series in agricultural science · 2023-08-15

  book-chapterSenior author

  The microbial safety of fresh fruits and vegetables impacts the health of consumers and the economic viability of farms, packinghouses, and the produce industry. The implementation of Good Agricultural Practices (GAPs) on farms and in packinghouses over the past 24 years has resulted in an increase in written farm food safety plans and targeted practices aimed at reducing the risks of microbial contamination. Growers have expanded their mindset and management practices to include food safety in addition to the myriad of other production goals including improving crop yield, controlling pests, maintaining market access, and ensuring postharvest quality. The focus of this chapter is to review the role of GAPs in preventing microbial contamination of fresh produce over time. This includes summarizing how GAPs have evolved, the impact they have had on the produce industry, current GAPs and how they are implemented, and projecting their relevance into the future.

  PublisherDOI

• Risk factors associated with the prevalence of Listeria monocytogenes in manured soils on certified organic farms in four regions of the United States

  Frontiers in Sustainable Food Systems · 2023-09-12 · 6 citations

  articleOpen access

  Introduction Biological soil amendments, including raw or untreated manure, are currently used to improve soil fertility, especially in organic operations that prohibit use of synthetic fertilizers. However, addition of untreated manure may pose a risk of contamination of fresh produce by pathogens of public health significance, including Listeria monocytogenes . Organic growers follow United States Department of Agriculture (USDA) National Organic Program regulations for raw manure use, which stipulate that harvest should commence no earlier than 90- or 120-days post-application, depending on direct contact between the edible portion of the produce and the soil. To inform the protection that such time-intervals provide, this study explored the farm-level risk factors associated with L. monocytogenes prevalence in USDA-certified organic farm soils amended with untreated manures. Methods A longitudinal, multi-regional study was conducted on 19 farms in four states (California, Minnesota, Maine, and Maryland) over two growing seasons (2017 and 2018). Untreated manure, soil, irrigation water, and produce samples were collected and cultured for L. monocytogenes. Mixed effect logistic regression was used to investigate risk factors associated with L. monocytogenes prevalence in soil. Results and Discussion Results showed that multiple factors influenced the odds of a soil-positive sample, including temporal [year (OR = 0.19), sampling day (OR = 0.09–0.48)] and weather-related [temperature range (OR = 0.48)] variables, manure characteristics [season of application (OR = 0.04, summer), presence of L. monocytogenes (OR = 2.89) and other pathogens in manure (OR = 5.24)], farm management factors [water source (OR = 2.73, mixed), number of year-round staff (OR = 0.02)], and soil characteristics [concentration of generic Escherichia coli (OR = 1.45), moisture (OR = 0.46), organic matter (OR = 7.30), nitrate (OR = 3.07), potassium (OR = 0.09) and calcium (OR = 2.48)]. This study highlights the complexity of L. monocytogenes prevalence in soil and contributes science-based metrics that may be used when determining risk-mitigation strategies for pathogen contamination.

  PublisherOA PDFDOI

• Risk factors associated with the prevalence of Shiga-toxin-producing Escherichia coli in manured soils on certified organic farms in four regions of the USA

  Frontiers in Sustainable Food Systems · 2023-03-27 · 12 citations

  articleOpen access

  Introduction Biological soil amendments of animal origin (BSAAO), including untreated amendments are often used to improve soil fertility and are particularly important in organic agriculture. However, application of untreated manure on cropland can potentially introduce foodborne pathogens into the soil and onto produce. Certified organic farms follow the USDA National Organic Program (NOP) standards that stipulate a 90- or 120-day interval between application of untreated manure and crop harvest, depending on whether the edible portion of the crop directly contacts the soil. This time-interval metric is based on environmental factors and does not consider a multitude of factors that might affect the survival of the main pathogens of concern. The objective of this study was to assess predictors for the prevalence of Shiga-toxin-producing Escherichia coli (non-O157 STEC) in soils amended with untreated manure on USDA-NOP certified farms. Methods A longitudinal, multi-regional study was conducted on 19 farms in four USA regions for two growing seasons (2017–2018). Untreated manure (cattle, horse, and poultry), soil, and irrigation water samples were collected and enrichment cultured for non-O157 STEC. Mixed effects logistic regression models were used to analyze the predictors of non-O157 STEC in the soil up to 180 days post-manure application. Results and discussion Results show that farm management practices (previous use with livestock, presence of animal feces on the field, season of manure application) and soil characteristics (presence of generic E. coli in the soil, soil moisture, sodium) increased the odds of STEC-positive soil samples. Manure application method and snowfall decreased the odds of detecting STEC in the soil. Time-variant predictors (year and sampling day) affected the presence of STEC. This study shows that a single metric, such as the time interval between application of untreated manure and crop harvest, may not be sufficient to reduce the food safety risks from untreated manure, and additional environmental and farm-management practices should also be considered. These findings are of particular importance because they provide multi-regional baseline data relating to current NOP wait-time standards. They can therefore contribute to the development of strategies to reduce pathogen persistence that may contribute to contamination of fresh produce typically eaten raw from NOP-certified farms using untreated manure.

  PublisherOA PDFDOI

• Norovirus transmission mitigation strategies during simulated produce harvest and packing

  International Journal of Food Microbiology · 2021 · 11 citations

  • Environmental health
  • Toxicology
  • Medicine
  PublisherOA PDFDOI

• Development of an Irrigation Water Quality Database to Identify Water Resources and Assess Microbiological Risks During the Production of Fresh Fruits and Vegetables

  Frontiers in Water · 2021-11-01 · 3 citations

  articleOpen access1st authorCorresponding

  An Irrigation Water Quality Database was developed to help assess the microbiological quality of irrigation water used in fruit and vegetable production in 15 counties in New York (NY) State. Water samples from Tennessee (TN) were also included in the database. Four water quality parameters, quantified generic Escherichia coli , specific conductance, pH, and turbidity, were tested. Ground, reservoir, and running water were sampled over 2 years (2009 and 2010), covering three seasons each year (spring, summer, and fall). TN data are for all three seasons in 2010 only. Overall in NY (254 total samples), ground water had a geometric mean of 1 most probable number (MPN)/100 ml, reservoir water had a geometric mean of 8 MPN/100 ml, and running water had a geometric mean of 52 MPN/100 ml. Overall in TN (63 total samples), ground water had a geometric mean of 1 colony forming unit (CFU)/100 ml, reservoir water had a geometric mean of 5 CFU/100 ml, and running water had a geometric mean of 38 CFU/100 ml. These values are all below the 126 MPN/100 ml United States Environmental Protection Agency's Ambient Water Quality Standards (AWQS) standard for fresh water. The presence of E. coli had very weak but sometimes statistically signficiant correlatation with water specific conductance, pH, and turbidity, depending on the water source but the r -squared effect was not strong enough to make the other measurements a substitute for testing specifically for E. coli in water.

  PublisherOA PDFDOI

• Survival and Persistence of Foodborne Pathogens in Manure-Amended Soils and Prevalence on Fresh Produce in Certified Organic Farms: A Multi-Regional Baseline Analysis

  Frontiers in Sustainable Food Systems · 2021 · 31 citations

  • Biology
  • Veterinary medicine
  • Agronomy

  Biological soil amendments of animal origin (BSAAOs), including untreated (e.g., raw or aged manure, or incompletely composted manure) and treated animal products (e.g., compost), are used for crop production and as part of soil health management. Application of BSAAO's must be done cautiously, as raw manure commonly contains enteric foodborne pathogens that can potentially contaminate edible produce that may be consumed without cooking. USDA National Organic Program (NOP) certified production systems follow the 90-or 120-day interval standards between applications of untreated BSAAOs and crop harvest, depending on whether the edible portions of the crops are in indirect or direct contact with the soil, respectively. This study was conducted to evaluate the survival of four foodborne pathogens in soils amended with BSAAOs and to examine the potential for bacterial transfer to fresh produce harvested from USDA NOP certified organic farms (19) from four states. Only 0.4% (2/527) of produce samples were positive for L. monocytogenes . Among the untreated manure and compost samples, 18.0% (42/233) were positive for at least one of the tested and culturable bacterial foodborne pathogens. The prevalence of non-O157 STEC and Salmonella in untreated manure was substantially > that of E. coli O157:H7 and L. monocytogenes . Of the 2,461 soil samples analyzed in this study, 12.9% (318) were positive for at least one pathogen. In soil amended with untreated manure, the prevalence of non-O157 STEC [7.7% (190) and L. monocytogenes (5.0% (122), was > that of Salmonella (1.1% (26)] or E. coli O157 [0.04% (1)]. Foodborne pathogen prevalence in the soil peaked after manure application and decreased significantly 30 days post-application (dpa). However, non-O157 STEC and L. monocytogenes were recovered from soil samples after 90 and 120 dpa. Results indicate that produce contamination by tested foodborne pathogens was infrequent, but these data should not be generalized outside of the specific wait-time regulations for organic crop production and the farms studied. Moreover, other sources of contamination, e.g., irrigation, wildlife, environmental conditions, cropping and management practices, should be considered. This study also provides multi-regional baseline data relating to current NOP application intervals and development of potential risk mitigation strategies to reduce pathogen persistence in soils amended with BSAAOs. These findings contribute to filling critical data gaps concerning occurrence of fecal pathogens in NOP-certified farming systems used for production of fresh produce in different US regions.

  PublisherOA PDFDOI

• Food safety regulations in the US and their impact on international produce growers and importers

  Acta Horticulturae · 2020-04-01

  article1st authorCorresponding

  ISHS XII International Rubus and Ribes Symposium: Innovative Rubus and Ribes Production for High Quality Berries in Changing Environments Food safety regulations in the US and their impact on international produce growers and importers

  PublisherDOI

• Assessing the costs and returns of on-farm food safety improvements: A survey of Good Agricultural Practices (GAPs) training participants

  PLoS ONE · 2020 · 24 citations

  Senior authorCorresponding
  • Business
  • Agricultural economics
  • Agricultural science

  Good Agricultural Practices (GAPs) training programs were developed to provide guidance to fruit and vegetable growers on how to reduce food safety risks on the farm. These programs have been enhanced over the years due, in part, to increasing buyer and regulatory requirements. However, the costs of implementing additional food safety practices has been identified as a primary barrier to long-term farm financial feasibility, particularly for smaller scale producers. A survey of past participants in New York State revealed that increasing food safety improvements facilitated by GAPs have not significantly impacted the size of farm operations or the types of crops grown. In terms of farm size, we show that both the financial costs and financial benefits of food safety improvements increase with farm size, but at decreasing rates. In so doing, relatively higher market sales gains per acre by smaller farms from additional food safety investments offset the relatively higher costs to them of their implementation. We also demonstrate that benefits of food safety improvements were significantly higher for farms that had third-party food safety audits and for those that market primarily through wholesale channels. The results should prove welcome by educators as they encourage participation by all scales of producers in GAPs trainings and for growers in understanding that food safety investments can support both reduced microbial risks and sales growth.

  PublisherOA PDFDOI

Frequent coauthors

• Randy W. Worobo

  Cornell University

  9 shared

• Robert B. Gravani

  Cornell University

  7 shared

• Donald M. Stoeckel

  University of Georgia

  7 shared

• Donna P. Clements

  Cornell University

  7 shared

• Patricia D. Millner

  Agricultural Research Service

  6 shared

• Gretchen L. Wall

  5 shared

• Anusuya Rangarajan

  Cornell University

  5 shared

• Robert J. Ferl

  University of Florida

  4 shared

Labs

• Produce Safety AlliancePI