Research Description:

    Dr. Yanbin Li's research interest is food processing and bioprocessing engineering, specifically in food safety engineering. He conducts research projects in three areas of food safety engineering: microbial detection, microbial control and microbial prediction.

Biosensors for rapid detection of pathogens

An immuno-electrochemical biosensor was developed using immuno-magnetic beads for separation of target bacteria and enzymatic reaction for generation of electrochemical signals measured through a tyrosinase electrode in a flow-injection analysis system. The biosensor could detect 8x102-5x105 cfu/ml of Salmonella Typhimurium in poultry carcass wash water within 2 h. The biosensor was further improved using a bienzyme electrode (tyrosinase–horseradish peroxidase biosensor) and this resulted in a lower detection limit, 100 cfu/ml for both S. Typhmurium and Escherichia coli O157:H7. At the same time, the capillary column-based bioseparator/bioreactor was developed to replace the separation method using immuno-magnetic beads. A chemiluminescent optical fiber biosensor was investigated for detection of S. Typhmurium and E. coli O157:H7 in food samples and the results showed the pathogens could be detected at 300 cfu/ml within 1.5 h. A PCR-based biosensing method also was developed for detection of S. Typhimurium and Campylobacter jejuni in poultry samples. As low as 2 cells/ml of bacteria could be detected within 3 h using the PCR-based biosensor. Impedance immunosenor was studied for detection of viable E. coli O157:H7 and S. Typhimurium, and this method could detect 10 cells within 5 h. The results of these biosensors showed great potentials for low detection limit (PCR-based and impedance), rapid and sensitive (chemiluminescent), accurate and reliable (electrochemical), simple and practical (immuno-optical), and viable cells (immuno-impedance) features in future applications. Microelectrodes, microfluidics and nanocrystal markers are currently being studied for their applications in biosensors.
These projects were supported by the grants from USAD/NRI, the Food Safety Consortium, ASTA and CSTAR. For biosensor research, Dr. Li collaborated with professionals in microbiology, chemistry and biochemistry, electrical engineering, physics, food science and poultry science. He was also involved in several research centers and institutes on campus, including Center for Sensing Technology and Research, Micro-Electronics and Photonics Program, High Density Electronics Center, Center of Excellence for Poultry Science, and Institute for Food Science and Engineering.
The biosensor research has resulted in six invention disclosures, two patents filed and two patents in filing, and a company, BioDetection Instruments, Inc., being incubated by Virtual Incubation Corporation, Fayetteville, AR, for technology transfer. As a cofounder, Dr. Li serves as Chief Technology Officer.

Models for microbial prediction and quantitative risk assessment

The predictive microbial models including the first and second generation models were developed for survival/growth/death and cross-contamination of S. Typhimurium and C. jejuni during poultry processing based on the data of both laboratory-scale and pilot-plant-scale experiments. A quantitative risk assessment model was developed based on Monte Carlo simulation using @RISK and Aanlytica software for S. Typhimurium and C. jejuni in poultry production and processing systems. The microbial models were used in the risk assessment model to predict the performance of pathogens. The simulation results provided the probability and consequence of poultry products contaminated with pathogenic bacteria. Sensitivity analysis presented the relationship between the risk and operation parameters or critical control points.
The research on microbial risk assessment models was initiated in 1997 and funded by the Food Safety Consortium. A team was formed by professionals in poultry science, food science and biological engineering to develop quantitative microbial risk models to study scientific basis for new regulations, assist the industry in practicing HACCP programs, and enhance food safety for the society. In 2000, a project was funded by USDA/CSREES to develop quantitative risk assessment models for poultry products and vegetables. Three universities (University of Arkansas, Oklahoma State University and University of Georgia) are currently collaborating to make systematic approach for the microbial risk assessment in research, education and extension.

Antimicrobial technologies for food processing

An electrical pasteurization system was designed and constructed for treatment of brine chiller water used to chill cooked poultry and meat products. Laboratory-scale tests had been finished for obtaining basic data to design the prototype equipment in pilot-plant-scale tests. The flow-through system could reduce Listeria monocytogenes in the brine by more than 1 log cfu/ml within 5 s. A recirculating mode of this system could eliminate L. monocytogenes in the brine after 30 min operation. At the same time, electrochemically activated water (ECAW), or electrolyzed water, was studied for treatment of fresh-cut vegetables to reduce E. coli O157:H7, S. Typhimurium and L. monocytogenes. The ECAW results showed that pathogenic bacteria on fresh-cut vegetables including broccoli, cauliflower, and sprouts could be reduced by more than 3 log cuf/ml after 5 min dipping or 15 s spraying treatments. Antimicrobial spray, using cetylpyridinium chloride, trisodium phosphate, electrolyzed water, chlorinated water, was investigated for inactivation of S. Typhimurium and C. jejuni attached to chicken carcasses during processing. Both laboratory scale and pilot plant scale spraying devices were designed and tested. The results showed that S. Typhimurium and C. jejuni on chicken carcasses could be reduced by 1-3 log, depending on chemical concentration, temperature, pressure and time. These technologies provide the food processing industry cost-effective ways for control of pathogenic bacteria in food products.
The research on microbial control, electrochemical pasteurization and antimicrobial spray for poultry processing, was funded by USDA/CSREES, EPRI/FTC, the Food Safety Consortium, ALKAR, US Poultry & Egg Association and supported by Tyson Foods, Inc., Simmons Foods, Inc., Electrochemical Technologies, Ltd., and Johnson Food Equipment, Inc. Three US patents were issued and two are pending based on the results of these research projects.

People: [GROUP PICTURE]

• Rami Al-Haddad , Graduate Research Assistant
  

  (B.S., Electrical Engineering, University of Jordan, Jordan), Graduate Research Assistant, MicroElectronics and Photonics Program. His research involves MEMS based impedance immunosensor for detection of pathogens in foods. 229 Engineering Hall; 479-575-6020; Fax 479-575-2846; ralhadd@urk.edu

• Byungchul Kim , Graduate Research Assistant

  (B.S., M.S., Food Science, Pukyong National University, Korea), Graduate Research Assistant, Department of Food Science. His research focuses on capillary immunosensor for detection of multiple pathogens in foods. O-419 Poultry Science; 479-575-7627; Fax 479-575-7139; bxk02@uark.edu

• Latrecia Lewis , Intern Research Assistant

  (Senior student, Alcorn State University), Intern Research Assistant, MicroElectronics and Photonics. She is involved in research on microelectrode based immunosensor for detection of E. coli. O-419 Poultry Science; 479-575-7627; Fax 479-575-7139; lalewis@uark.edu

• Zhihui Liu , Graduate Research Assistant

  (B.S. Food Engineering, M.S. Food Science, China Agricultural University, China; M.S., Food Science, University of Arkansas), Graduate Research Assistant, Department of Biological and Agricultural Engineering. He is working with research on electrochemical treatment of chilling brine to reduce bacterial contamination in meat processing. O-419 Poultry Science; 479-575-7627; Fax 479-575-7139; zxl02@uark.edu

• Xiaole Mao , Graduate Research Assistant

  (B.Eng., Biotechnology, Southern Yangtze University, China), Graduate Research Assistant, Department of Biological and Agricultural Engineering. His research involves MEMS-based DNA/RNA sensors for detection of pathogenic bacteria. O-419 Poultry Science; 479-575-7627; Fax 479-575-7139; xmao@uark.edu

• Abani Pradhan , Graduate Research Assistant

  (B. Tech., Agricultural Engineering, Orissa University of Agriculture and Technology, India; M.Tech., Agricultural and Food Engineering, Indian Institute of Technology-Kharagpur, India), Graduate Research Assistant, Department of Biological and Agricultural Engineering. His research focuses on antimicrobial treatment in food processing, microbial predictive models and microbial risk assessment simulation in food safety. O-419 Poultry Science; 479-575-7627; Fax 479-575-7139; apradhan@uark.edu

• Betty Swem , Research Specialist

  (B.S., Animal Science; M.S., Food Science, University of Arkansas), Research Specialist, Department of Poultry Science. Her research involves antimicrobial methods for food processing. O-420 Poultry Science; 479-575-7129; Fax 479-575-7139; blstrou@uark.edu

• Xiaoli Su , Research Associate

  (B.A.Pharmacy, Hunan College of Traditional Chinese Medicine; M.S., Pharmacy, China Pharmaceutical University; Ph.D Analytical Chemistry, Hunan University, China), Research Associate, Department of Biological and Agricultural Engineering. He is working with research on biosensors for rapid detection of pathogens in foods. O-413 Poultry Science; 479-575-6101; Fax 479-575-7139; xsu@uark.edu

• Madhukar Varshney, Graduate Research Assistant

  (B.Tech., Food Engineering, MGCGV University; M.Tech., Chemical Technology, HBTI, India; M.S., Biological Engineering, University of Arkansas), Graduate Research Assistant, Department of Biological and Agricultural Engineering. His research focuses on MEMS based optical immunosensors for detection of pathogenic bacteria in food products. O-419 Poultry Science; 479-575-7627; Fax 479-575-7139; mvarshn@uark.edu

• Liju Yang, Graduate Research Assistant

  (B.S., Hangzhou Normal University, M.S., Hangzhou University, China), Graduate Research Assistant, Department of Biological and Agricultural Engineering). She is working on impedance immunosensors for detection of multiple pathogens. O-413 Poultry Science; 479-575-6101; Fax 479-575-7139; lyang@uark.edu

Alumni:

• Darrel Fos, Research Assistant
  
• Yongcheng Liu, Research Associate

  [Research Interests: Immuno-optical, chemiluminescent and PCR-based optical biosensors for rapid detection of pathogenic bacteria in poultry and meat products]

• Chuanmin Ruan, Research Associate

  [Research Interests: Immuno-electrochemical and immuno-impedance biosensors for rapid detection of E. coli O157:H7 and Salmonella typhimrium in food samples]

• Shengyao Wang, Graduate Research Assistant

  [Research Interests: Quantitative microbial risk assessment models for poultry products]

• Hong Yang, Research Specialist

  [Research Interests: Predictive models of Salmonella typhimurium and Campylobacter jejuni during poultry processing]

• Ira Zakariadze, Research Associate

  [Research Interests: Quantitative risk assessment models for Salmonella typhimurium and Campylobacter jejuni in poultry]

Laboratories:

• Biosensors and Bioinstrumentation (POSC L-224) [PICTURE]
  - Impedance analyzers
  - Spectrophotometers
  - Electrochemical Detectors (QCM, SPR, Fluorescent Microscopes)
  - Voltmatic Stat
  - PCR
  - Luminometer
  - Fluorescent detector
  - Centrifuges
  - Incubators, ovens, water baths
  - Water purification unit
  - Electronic instruments, such as oscilloscopes, function generators, data acquisition units, power supplies
  - Balances, pH meters
  - Votex mixers, shakers, hotplates and magnetic stirrers
  - Chemical Hoods
  
  
• Microbial Detection (POSC L-222) [PICTURE]
  - Spiral plater and auto counter
  - Incubators
  - CO2 incubators
  - Dispensors, ovens, water baths
  - Refrigerators and ultra-low freezer
  - Biological and chemical hoods
  
  
• Microbial Control and Modeling (POSC L-221) [PICTURE]
  - ECA reactors
  - Programmable power supplies
  - Simulated poultry chiller bath
  - Colorimeters, pH meters, conductivity meters, thermometers
  - Recirculating programmable water and oil baths
  - PC-based data acquisition units
  - Software: MATLAB (Simulator, Fuzzy Control, Neural Network, Statistics, etc.), Visual C++, Visual BASIC, @RISK, Analytica, JMP, SAS, AutoCAD.
  
  

Research Projects:

• Microbial Control:
  - Electrochemically Activated Water Treatment of Fresh-Cut Fruits and Vegetables MORE...
  - Antimicrobial Spray Methods in Poultry Processing MORE...
  - Bacterial Control System for Brine Chillers MORE...
  
  
• Microbial Detection:
  - Immuno-Electrochemical Biosensor for Detection of S. typhimurium and E. coli O157:H7 MORE...
  - Immuno-Optical Biosensor for Detection of Pathogens in Poultry and Meat Products MORE...
  - Chemiluminescent Fiber Optic Biosensor for Detection of Pathogens in Foods MORE...
  - PCR-Based Optical Biosensor for Detection of S. typhimurium and C. jejuni in Poultry MORE...
  - Rapid Detection of Bacteria Using Immuno-Fluorescence and Image Analysis MORE...

• Microbial Prediction:
  - Predictive Models of S. typhimurium and C. jejuni in Poultry Processing MORE...
  - A Quantitative Microbial Risk Assessment Model for Poultry Processing MORE...
  - Systematic Approach to Food Safety Risk Assessment from Producers through Retailers MORE...
  
  

Open Positions:

• No position open at present
  

Inquiries:

For further inquiries please feel free to contact me at:

Dr. Yanbin Li, Professor
Biological and Agricultural Engineering Department
University of Arkansas
230 Engineering Hall
Fayetteville, Arkansas 72701
Phone: (479) 575-2881, Fax: (479) 575-2846
E-mail: yanbinli@uark.edu