About

Lin Walker is an Assistant Professor in the Prestage Department of Poultry Science at NC State University. Her research and extension efforts focus on improving the microbial safety and quality of poultry and poultry products. Her goal is to assist the poultry industry in mitigating microbial safety risks and ensuring compliance with federal and state food safety regulations. Dr. Walker's research interests include intervention technologies to control food-borne pathogens, predictive microbiology to estimate the growth and survival of pathogens, thermal and non-thermal processing methods to enhance the safety and quality of poultry products, rapid detection techniques for food-borne pathogens, and Cochlosoma disease in turkeys. Before joining NC State, Dr. Walker was the team lead of Pathogen Detection in the Department of Research and Development at Neogen Corporation, an international food safety and animal safety company. During her tenure there, she developed rapid diagnostic test kits for food-borne pathogens and received the first-place J. Mac Goepfert Developing Scientist Award from the International Association of Food Protection in 2015. She holds a B.S. and M.S. from China Agricultural University in Food Quality and Safety and Processing and Storage of Agricultural Products, respectively, and earned her Ph.D. in Food Science and Technology from the University of Nebraska - Lincoln in 2014.

Research topics

• Food science
• Biology
• Microbiology
• Animal science
• Biochemistry
• Mathematics
• Ecology
• Veterinary medicine
• Chemistry

Selected publications

• The effect of housing system and broiler breed on meat quality1

  Poultry Science · 2026-04-27

  articleOpen access

  This study investigated the effects of the silvopastoral (SP) rearing system compared with a conventional (CV) indoor system, along with the influence of broiler breed (fast-growing, FAST vs. slow-growing, SLOW), on carcass traits (yields), meat quality, myopathy incidence, fatty acid profile, oxidative stability (TBARS), and sensory attributes. A 2 × 2 factorial design was conducted, using 250 birds per treatment, with 5 replicate pens (50 birds/pen). For data collection, 10 birds were selected from each pen for processing, giving a total of 5 replicates and 50 samples per treatment. FAST consistently exhibited superior carcass and breast yields, while SLOW had minimal breast muscle myopathies, regardless of the system. Several physicochemical traits were primarily influenced by the breed, with SLOW's breast exhibiting a greater content of connective tissue and shear force. In comparison, FAST exhibited greater moisture content. The housing system influenced lipid composition and oxidative stability, with SP meat exhibiting lower saturated fatty acid content than CV (40.16% vs. 42.04%) and reduced TBARS values (1.50 vs. 1.59 mg MDA/kg). However, the effect of SP on FAST was limited, as cooking loss did not differ between SP and CV systems (30.91% vs. 32.76%). Sensory results showed minimal differences; meat from CV birds was rated slightly juicier, while SLOW's meat was described as chewier and gummier. Overall, trade-offs were identified between yield performance and meat quality; meat from fast-growing birds had greater production efficiency but exhibited a greater incidence of muscular abnormalities. SP production demonstrated the potential to enhance certain meat quality traits without compromising sensory acceptance, albeit at a lower yield expense.

  PublisherDOI

• Assessing disease pathology from Cochlosoma anatis in turkey poults

  The Journal of Applied Poultry Research · 2026-02-27

  articleOpen accessSenior authorCorresponding

  Cochlosoma anatis is a flagellated protozoan parasite implicated in enteric disease (cochlosomiasis) of turkeys in commercial production. Research evaluating the effects of cochlosomiasis on turkey poults, where the disease is typically at its most severe, is lacking. Commonly observed cochlosomiasis symptoms include depressed weight gain, flock non-uniformity, lethargy, watery diarrhea, and co-infections. No commercially approved treatments or vaccines are available to combat cochlosomiasis. This study hypothesized that oral inoculation of C. anatis into turkey poults would lead to cochlosomiasis. Physiological and morphological analyses included blood chemistry, nutrient digestibility, and gut permeability. Disease effects were evaluated at 28 days of age in off-sex male turkey poults following inoculation with C. anatis at 14 days of age. Infection resulted in weight gain deficiencies; however, flock uniformity was not affected, contrary to field observations, which are likely related to the timing of infection relative to the bird’s age. Feed consumption was lower, and the feed conversion ratio was increased in infected cages. Amino acid digestibility was lower in infected birds, providing a potential partial explanation for the poor weight gain associated with cochlosomiasis. Blood chemistry analyses revealed metabolic alkalosis partially compensated for by respiratory carbon dioxide retention. Intestinal permeability was not significantly different between the groups. Overall, the disease effects observed in this study aligned mainly with traditional observations of cochlosomiasis. Flock non-uniformity may be the result of a complex of multiple issues that require exploration. The disease characterization presented here offers potential explanations, highlighting areas that suggest further research focus.

  PublisherDOI

• The Minimum Growth Temperatures of Shiga Toxin–Producing <i>Escherichia coli</i>

  Foodborne Pathogens and Disease · 2025-03-03

  article1st authorCorresponding

  The objective of this study was to determine the minimum growth temperature of Shiga toxin–producing Escherichia coli (STEC). Forty-eight strains of STEC, including E. coli O157:H7, O104:H4, O26, O45, O103, O111, O121, and O145, were inoculated into tryptic soy broth (TSB) at ca. 6.0 CFU/mL and incubated at temperatures ranging from 5°C to 11°C. The lowest temperature at which growth occurred was determined as the minimum growth temperature of the strain. The minimum growth temperature varied among strains, but the strain difference was within 2–3°C. All of the STEC strains grew at ≥10.3°C. Majority of the STEC strains (31/48) grew at 8.9°C, with some strains (10/48) being able to grow at as low as 8.0°C. None of the STEC serogroups were able to grow at ≤7.4°C. E. coli O104:H4 and O157:H7 had relatively lower minimum growth temperatures, with 8°C and average 8.4°C, respectively, whereas serogroup O26 had a higher minimum growth temperature (average 9.6°C). The results of this study provide basic but critical information on STEC growth and could be used either in fundamental research or to mitigate the risk of STEC from food products by storing them at temperatures below the minimal growth temperature.

  PublisherDOI

• Infection with Cochlosoma anatis in early brooding leads to poor health outcomes in turkey poults

  The Journal of Applied Poultry Research · 2025-11-05 · 1 citations

  articleOpen accessSenior authorCorresponding

  Infection with Cochlosoma anatis , a flagellated protozoan parasite, significantly impacts U.S. commercial turkey production by causing poult enteritis (poor weight gain, flock non-uniformity, and diarrhea) and is associated with co-infections. Though unconfirmed, prior research suggests impaired nutrient acquisition or utilization. This study investigated how infection timing affects disease severity in turkey poults, hypothesizing that inoculation at early brooding (placement or 8 days of age) would lead to more severe outcomes relative to inoculation at 15 days of age or non-infected controls (NC). Poults were orally inoculated with a C. anatis field strain and performance recorded for 28 days. Ileal C. anatis concentrations and cecal tonsil concentrations of Escherichia coli , total coliforms, Clostridium perfringens , and Salmonella were measured at 28 days of age. Mortality was normalized with the Freeman-Tukey double arcsine transformation, and all parameters were assessed using a one-way ANOVA and Tukey-Kramer mean separation in JMP Pro 16. Mortality was significantly higher (p=0.0007) with inoculation at placement and 8 days of age (up to 70%) compared to those inoculated at 15 days of age (16%) and the NC group (8%). Initial weights were similar; however, poults inoculated at placement had significantly lower (p<0.0001) final body weights (408.42 g/poult) compared to inoculation at 8 and 15 days of age (∼587 g/poult) and the NC group (797.51 g/poult). C. anatis and bacterial concentrations did not significantly differ. This study showed that C. anatis infection in early brooding leads to severe disease, highlighting the fragility of young poults susceptible to C. anatis infection.

  PublisherDOI

• Oral inoculation of turkeys with in vitro cultured Histomonas meleagridis in cecal contents results in histomonosis

  The Journal of Applied Poultry Research · 2025-06-05 · 2 citations

  articleOpen access

  This study examined the effect of oral administration of Histomonas meleagridis on infection rate and disease progression of histomonosis in turkeys. Experiment 1, poults were placed in 3 experimental groups consisting of H. meleagridis culture in media administered via intracloacal inoculation (CIM), oral inoculation (OIM), or oral inoculation mixed with previously frozen cecal content (OICC). Poults were inoculated with 50,000 histomonads at 8 AM and 5 PM for five days starting from 14-day of age. Cloacal inoculation (CIM) produced 100% infection rates, while oral infection with H. meleagridis in media (OIM) led to 8% infection. However, oral inoculations using cecal content (OICC) produced 43% infection rates (P = 0.0003). In experiment two, poults were placed in 2 experimental groups consisting oral inoculations with fresh cecal contents containing H. meleagridis (OI) and intracloacal inoculations with fresh cecal contents containing H. meleagridis (CI). Poults were inoculated with 50,000 histomonads at 8 AM and 5 PM for five days starting from 14-day of age. Oral inoculations (OI) produced 90% infection rates, similar to the cloacal route (CI) at 93% (P = 0.6433). In Experiment 3, individual isolates of H. meleagridis in cecal content were administered orally: Buford isolate (BUF), Arkansas isolate (ARK), or Zeeland, Michigan isolate (ZMI). Results showed BUF and ARK isolates produced higher infection rates than the ZMI isolate (P = 0.0136). In summary, oral infection in turkeys with H. meleagridis could be achieved using cecal content and infection rates and disease progression are impacted by isolate and inoculum condition.

  PublisherDOI

• Modeling the growth/no growth response of Non-O157 Shiga toxin-producing Escherichia coli to temperature, pH and water activity

  LWT · 2024 · 3 citations

  1st authorCorresponding
  • Microbiology
  • Food science
  • Biology

  The objective of this study was to model the effect of temperature, pH and water activity (aw) on the growth/no growth response of non-O157 Shiga toxin-producing E. coli (STEC). A cocktail of six-serogroup STEC was inoculated into brain heart infusion broth (BHI) with 48 combinations of different pH and aw, and the inoculated medium was incubated at one of ten temperatures. After 62 days of incubation, growth was determined by turbidity and plating on tryptic soy agar. Binary data (0 [no growth] or 1 [growth]) were fitted into a nonlinear logistic regression and the parameters were estimated. The model was validated with independently produced data from seven serogroups of non-O157 STEC, a cocktail of E. coli O157:H7, and two panels of six-serogroup of STEC. The non-O157 STEC did not grow at temperatures ≤ 6 °C and ≥ 47 °C, and the highest tolerance to pH and aw occurred at 25 °C. Although slight difference in the growth/no growth response was observed among different groups of STEC, the developed model can be applied to all the STECs with an average concordance of 92.3%. This work provides valuable insight into the growth/no-growth response of STEC under various environmental conditions.

  PublisherDOI

• Cochlosoma anatis in Poultry and its Industry Impact

  Avian Diseases · 2024-06-06 · 3 citations

  reviewSenior author

  Estudio recapitulativo- Cochlosoma anatis en la avicultura comercial y su impacto en esta industria. Cochlosoma anatis es un parásito protozoario flagelado clasificado dentro de la familia Trichomonadidae y es el agente causante de la coclosomiasis, que es una enfermedad entérica de pavos, aves acuáticas y otras aves silvestres. Los signos de la coclosomiasis consisten principalmente en diarrea acuosa, aves con letargo, disminución de la ganancia de peso y morbilidad generalizada de las parvadas, lo que provoca su falta de uniformidad. La distribución conocida de C. anatis gira en torno a zonas de granjas de producción de pavos en el sudeste de los Estados Unidos, principalmente en Misuri y Arkansas, pero se ha notificado su presencia en otros estados y en algunos otros pa'ıses. El diagnóstico se confirma mediante el examen de raspados de mucosa entérica con microscop'ıa óptica. Tras el retiro de la aprobación de medicamentos antiprotozoarios eficaces para su uso en la producción animal comercial, la coclosomiasis se ha convertido en una preocupación importante para los profesionales de la industria de pavos comerciales. La transmisión de C. anatis se produce por v'ıa fecal-oral, pero es frágil fuera del hospedador, lo que sugiere la participación de un vector en la introducción de la enfermedad en granjas susceptibles. La investigación sobre la patogenicidad, la transmisión y el efecto ambiental de C. anatis ha sido limitada, lo que crea un vac'ıo en el conocimiento de la coclosomiasis. En el futuro será necesario investigar más a fondo las formas de prevenir y tratar la coclosomiasis, con la necesidad de enfocarse en la patogenia de la enfermedad, los patrones de transmisión y los métodos de profilaxis y tratamiento.

  PublisherDOI

• Impact of Stocking Densities on the Microbiota of the Cloaca, Eggshell, and Egg Content of White Egg Layers in Colony Cages

  Poultry · 2023 · 3 citations

  Senior authorCorresponding
  • Biology
  • Animal science
  • Food science

  Food safety is a major concern for commercial poultry producers and consumers. Currently, there is also pressure from retailers and legislators to increase the space per hen in cages. Five different density treatments consisting of six (208 in2/bird), nine (139 in2/bird), twelve (104 in2/bird), fifteen (83 in2/bird), and eighteen birds (69 in2/bird) per cage were examined in colony cage environments. Microbiological tests were performed at 39, 55, and 68 weeks of age. The populations of total aerobic bacteria; E. coli/coliform; Enterobacteriaceae; and yeasts and molds from an eggshell rinse, egg content, and cloacal swabs were enumerated. The prevalence of Salmonella spp. in these samples was also monitored. Overall, no bacteria were detected in any of the egg content, and there were no differences (p &gt; 0.05) between treatments for the shell rinse. Stocking density did not influence the eggshell microbiota of the hens. Hens housed at 104 in2 per hen showed higher levels of total aerobic bacterial counts from the cloaca compared to hens at 208 in2 and 69 in2 per hen. Hens housed at 139 in2 per hen had the highest level of cloacal molds. This research demonstrates that stocking density does not influence eggshell microbiota or Salmonella contamination of the eggshell or cloaca, thereby indicating that allowing more space per hen will not positively or negatively affect the prevalence or concentration of foodborne pathogen-associated bacteria in or on the eggs.

  PublisherOA PDFDOI

• Growth comparison and model validation for growth of Shiga toxin-producing Escherichia coli (STEC) in ground beef

  LWT · 2023 · 6 citations

  1st authorCorresponding
  • Food science
  • Animal science
  • Biology

  The aim of this study was to compare the growth of non-O157 Shiga toxin-producing Escherichia coli (STEC) with E. coli O157:H7 in ground beef and modified Tryptic Soy Broth (TSB). Additionally, the performance of three available models (ComBase, Huang et al. model, and Cepeda et al. model), for predicting STEC growth in ground beef was evaluated. To achieve this, eleven groups of STEC, including E. coli O157:H7, were inoculated into irradiated ground beef (7% or 27% fat) or modified TSB, and then subjected to programmed water baths to follow time-varying sinusoidal temperature profiles for 300 h (low temperature, 5–15 °C) and 25 h (high temperature, 10–40 °C). The growth data of STEC in ground beef were fitted to the three models, and model performance indices such as mean relative percentage error (MRPE), mean absolute relative error (MARE), root mean squared error (RMSE), bias factor (BF) and accuracy factor (AF) were calculated to assess their accuracy in predicting STEC growth. The study found that the growth of non-O157 STEC was similar to that of E. coli O157:H7, indicating that growth models for E. coli O157:H7 can be used to predict the growth of non-O157 STEC. The fat content did not significantly affect STEC growth in ground beef. Among the three models tested, the Huang et al. model underestimated the growth of all STEC in ground beef, with an RMSE of up to 2.14 log CFU/g. The ComBase model also under-predicted STEC growth in ground beef at high temperatures (10–40 °C) and could not predict growth at temperatures below 10 °C, where STEC might grow slowly. In contrast, the Cepeda et al. model accurately predicted STEC growth in ground beef and is considered an conservative growth model for STEC in commercial ground beef products. In summary, this study provides important insights into the growth of non-O157 STEC and E. coli O157:H7 in ground beef and their modeling, which can aid in predicting the safety of commercial ground beef products.

  PublisherDOI

• Review for "Assessment of foodborne transmission of &lt;i&gt;Salmonella enteritidis&lt;/i&gt; in hens and eggs in Bangladesh"

  2022-02-11

  peer-reviewOpen access1st authorCorresponding
  PublisherDOI

Frequent coauthors

• Shengqian Sun

  4 shared

• J. Lowery

  North Carolina State University

  2 shared

• Harshavardhan Thippareddi

  University of Georgia

  2 shared

• Ramon D. Malheiros

  North Carolina State University

  1 shared

• Benjamin N. Alig

  North Carolina State University

  1 shared

• Harshavardha Thippareddi

  1 shared

• Randall K. Phebus

  Kansas State University

  1 shared

• Nathan Anderson

  Center for Food Safety and Applied Nutrition

  1 shared

Labs

• Prestage Department of Poultry SciencePI

Awards & honors

• First-place J. Mac Goepfert Developing Scientist Award from…