Location: Warmwater Aquaculture Research Unit
2023 Annual Report
Objectives
Research will address methods to determine the presence of pathogens in catfish/catfish products and to maximize elimination methods. Detection techniques will be developed to aid in processing and packaging operations, which should further enhance product safety. Specifically the new objectives are:
1. Optimize safety of aquaculture products through innovative processes for reducing microbiological, physical and chemical hazards in seafood/aquaculture products.
2. Determine the mechanisms influencing microbial survival of selected pathogens in seafood/aquaculture products.
3. Optimize the market value of seafood/aquaculture products through enhanced food safety and quality.
Approach
Catfish: Determine optimum rates of microbial reduction through innovative processing in catfish products including evaluation of consumer acceptance. Determine viable methods of hazard reduction (smoking, acidulants, antimicrobials, etc) in catfish products during processing and storage. Determine the methods by which these methods reduce hazards within the products evaluated. Enhance the physical safety of catfish fillets with innovative analysis technology.
Seafood/Produce: Determine the efficacy of IQF freezing, irradiation, and high pressure processing and other technologies on the safety and quality of oysters, shrimp and produce.
Objective 2. Catfish/ Seafood/Produce: Determine the mechanistic approach by which the certain pathogenic bacteria may be reduced in aquatic species. Utilize PCR analysis and other assays to determine the sensitivity and specificity of various isolates in response to innovative treatments.
Objective 3. Catfish: Enhance product value through innovative smoking and further processing of catfish fillets. Value-added analysis will compared products to commodity value for product enhancement addition. Evaluate value-added products to address potential food safety issues.
Seafood/Produce: Evaluate consumer acceptance of products enhanced through various processing methods. Preparation techniques, ingredient inclusion, packaging and storage methods will be evaluated at various time frames and inclusion rates to determine specie specific parameters limitations. Analyze economics of various market potentials.
Catfish: Determine optimum rates of microbial reduction through innovative processing in catfish products including evaluation of consumer acceptance. Determine viable methods of hazard reduction (smoking, acidulants, antimicrobials, etc) in catfish products during processing and storage. Determine the methods by which these methods reduce hazards within the products evaluated. Enhance the physical safety of catfish fillets with innovative analysis technology.
Seafood/Produce: Determine the efficacy of IQF freezing, irradiation, and high pressure processing and other technologies on the safety and quality of oysters, shrimp and produce.
Objective 2. Catfish/Seafood/Produce: Determine the mechanistic approach by which the certain pathogenic bacteria may be reduced in aquatic species. Utilize PCR analysis and other assays to determine the sensitivity and specificity of various isolates in response to innovative treatments.
Objective 3. Catfish: Enhance product value through innovative smoking and further processing of catfish fillets. Value-added analysis will compared products to commodity value for product enhancement addition. Evaluate value-added products to address potential food safety issues.
Seafood/Produce: Evaluate consumer acceptance of products enhanced through various processing methods. Preparation techniques, ingredient inclusion, packaging and storage methods will be evaluated at various time frames and inclusion rates to determine specie specific parameters limitations. Analyze economics of various market potentials.
Progress Report
Progress was made on all objectives and their sub-objectives, all of which have a major focus on the ensuring the food safety of catfish, seafood and produce, and are under the National Program 108-Food Safety, Component I: Food Borne Contaminants. The third objective also has a focus on the food quality improvement under the National Program 306-Quality and Utilization of Agricultural Products, Component I: Foods. Production, processing and distribution of fish, seafood and produce are very diverse and extensive, and the system is vulnerable to the introduction of contaminants through the environment, natural processes, and the delivery system. Protease inhibitor including trypsin inhibitor in soybean and whey were studied as they could be used as an ingredient for enhancing fish products.
In support of Objective 1, significant progress was made to optimize the safety of aquaculture products through innovative processes for reducing microbiological, physical, and chemical hazards in seafood/aquaculture products. In this period, we continued to acquire critical research equipment and have them installed and personnel trained. The major achievement was to complete the installation of an exhaust system for a wet chemistry laboratory. In addition, about $8 million were acquired from the state sources for building a Northern Gulf Aquatic Food Research Center (NGAFRC), for the first phase of building construction for the NGAFRC on a piece of 4-acre land, which was purchased last year. We have met with architects on planning laboratories to begin building in Spring of 2023. Currently, the seafood research laboratory is locating at near the sea level and subject to flood.
We continued to foster our partnership with the USDA-Agricultural Research Service (ARS) and the catfish aquaculture and processing industry to improve the safety and quality of the fillet and by-products. We have completed a high hydrostatic pressure processing project investigating the inactivation of bacteria in oysters produced by an oyster aquaculture farm in Alabama by using hydrostatic pressure up to 600 mPa and time from one to five minutes. Data have been collected and analyzed, and a manuscript is being prepared for publication.
In support of Objective 2, we continued to determine the mechanistic approach, by which certain pathogenic bacteria may be reduced in catfish, seafood and produce. We have successfully completed the experiments to enhance the detection of pathogenic Vibrio vulnificus in oysters by using an innovative recombinase-polymerase system in conjunction with a lateral flow dipstick assay. The method is more sensitive and rapid for screening than the FDA-approved methods for Vibrio analyses and will be very useful to oyster aquaculture and processing industries for controlling these pathogens. The method is more sensitive than traditional culture-gene probe method or the polymerase chain reaction (PCR) method. Results from our collaboration of the USDA-ARS laboratory in Delaware and the Texas A&M University, on testing the effectiveness of riboflavin would affect norovirus inactivation by x-ray irradiation has been written into a manuscript. Progress was made continuously on the development of low-level tolerance to antibiotic trimethoprim in Listeria monocytogenes after sublethal adaptation to quaternary ammonium compound (QAC). Using eight L. monocytogenes strains, researchers in the Department of Food Science, Nutrition, and Health Promotion at the Mississippi State University determined, the changes in short-range of minimum inhibition concentrations (MIC), growth rate, and survival for heterologous stress response to trimethoprim, after sublethal exposure to daily cycles of fixed or gradually increasing concentration of QAC. When adapted to daily cycles of fixed or gradually increasing sublethal concentrations of QAC, three main findings were found in eight L. monocytogenes strains against trimethoprim: (a) 3 of the 8 strains exhibited significant increases in short-range minimum inhibitory concentration (MIC) of trimethoprim by 1.7 to 2.5 fold in QAC-adapted subpopulations as compared to non-adapted cells; (b) 2 of the 8 strains exhibited significant increase in growth rate in trimethoprim by 1.4 to 4.8 fold in QAC-adapted subpopulations compared to non-adapted cells; and (c) 5 of the 8 strains yielded significantly higher survival by 1.3-to-3.1 log CFU/mL in trimethoprim in QAC-adapted subpopulations compared to the non-adapted control. However, for 3/8 strains of L. monocytogenes, there were no increases in the survival of QAC-adapted subpopulations compared to non-adapted control in trimethoprim. These findings suggest the potential formation of low-level trimethoprim tolerant subpopulations in some L. monocytogenes strains where QAC may be used widely. A refereed journal article on this subproject was recently published in a peer-reviewed journal of ‘Foods’ this year.
In support of Objective 3, progress was made on the optimization of the extraction of proteins from catfish by-product, which included heads and bones from the fillet processing industry. Researchers in the Experimental Seafood Processing Laboratory (ESPL) in the Coastal Research and Extension Center of the Mississippi State University, continued to develop innovative methods for improving the color and texture of the surimi-like gels using water washing and the use of soy whey containing protease inhibitors. In the meantime, soybean and soymilk that contain trypsin inhibitors as affected by cultivars and food processing technologies were investigated. Results have been analyzed and reported in three peer-reviewed refereed journals. A tenure-track faculty position on food mechanical engineering was established to engage with the catfish processing industry to assist the processors to enhance meat yield and processing efficiency. If more meat can be recovered, catfish processing economy will be enhanced. Researchers at the ESPL also have completed the making of fish balls using the meat of oversized catfish, which are considered as byproduct since they cannot be processed by the normal setting of the automated filleting machine. Potato starch was found to enhance firmness of the fish balls, whereas seaweed and bacterial gums were found to weaken the gels of the fish balls. An international collaboration with Taiwan’s National Kaohsiung University of Science and Technologies led to two joint publications focusing on the use of high-hydrostatic pressure processing to extend the shelf-life of clam and milkfish fillet during cold storage, and to enhance meat yield. The findings can be applied to oyster and catfish product processing in the near future.
Accomplishments
1. Reducing pathogenic bacteria in catfish, seafood and produce. In support of our objectives, ARS researchers in Stoneville, Mississippi, continued to determine the mechanistic approach, by which certain pathogenic bacteria may be reduced in catfish, seafood and produce. Our researchers have successfully submitted their work for publication in the Journal of Food Protection on enhancing the detection of pathogenic Vibrio vulnificus in oysters by using an innovative recombinase polymerase system in conjunction with a lateral flow dipstick assay. The method is more sensitive and rapid for screening than the FDA approved methods for Vibrio analyses and will be very useful to oyster aquaculture and processing industries for controlling these pathogens. The manuscript has been accepted for publication. Results from our researcher collaboration with the USDA-ARS laboratory in Delaware and the Texas A&M University, on testing the effectiveness of riboflavin would affect norovirus inactivation by x-ray irradiation has been written into a manuscript and submitted to the journal of Radiation Physics and Chemistry. Progress was made continuously on the development of low-level tolerance to antibiotic trimethoprim in Listeria monocytogenes after sublethal adaptation to quaternary ammonium compound (QAC). Using eight L. monocytogenes strains, researchers in the Department of Food Science, Nutrition, and Health Promotion at the Mississippi State University, determined the changes in short-range of minimum inhibition concentrations (MIC), growth rate, and survival for heterologous stress response to trimethoprim, after sublethal exposure to daily cycles of fixed or gradually increasing concentration of QAC.
2. Development of innovative technologies for preventing illness caused by pathogens and chemical residues in foods. In further support of our objectives, ARS researchers in Stoneville, Mississippi, have continued to develop innovative technologies for preventing illness that may be caused by pathogens and chemical residues in foods. Substantial progress was made to optimize the safety of aquaculture products through innovative processes for reducing microbiological, physical, and chemical hazards in seafood/aquaculture products. In this period, we continued to acquire critical research equipment and have them installed and personnel trained. The major achievement was to complete the installation of several pieces of equipment for processing fish and fermentation. A complete canning laboratory with heat penetration was purchased and will be installed as soon as space is available. To increase space for research, about $8 million were acquired from the state sources to construct the Northern Gulf Aquatic Food Research Center (NGAFRC). We have met with architects on planning laboratories to begin building in Fall of 2023. Currently, our seafood research laboratory is located near the sea level and subject to flooding risk from hurricane storm surge.
3. High hydrostatic pressure processing project. ARS researchers in Stoneville, Mississippi, continued to foster our partnership with the USDA-Agricultural Research Service (ARS) and the catfish aquaculture and processing industry to improve the safety and quality of the fillet and by-products. We have completed a high hydrostatic pressure processing project investigate the inactivation of bacteria in oysters produced by an oyster aquaculture farm in Alabama by using hydrostatic pressure up to 600 mPa and time from one to five minutes. Data have been collected and analyzed, and a manuscript is being prepared for publication. In addition, soymilk is being made by using ultrahigh temperature heating to inactivate pathogens and trypsin inhibitors, and to reduce precipitation residues in food packages. This research is being continued.
4. Development of processing technologies for value-added utilization of foods. ARS researchers in Stoneville, Mississippi, have continued to characterize food materials and develop novel processing technologies for value-added utilization of foods produced in Mississippi. We have collaborated with USDA-ARS Soybean Genetic Research Unit in Stoneville, Mississippi, and with the University of Missouri to plant soybeans with different glycinin and beta-conglycinin composition for making value-added soy foods. More than 25 selected soybean lines were planted and characterized. Results are being analyzed. In the meantime, soybean and soymilk that contain trypsin inhibitors as affected by cultivars and food processing technologies were investigated. Progress was made on the optimization of the extraction of proteins from catfish by-product, which included heads and bones from the fillet processing industry. We continued to develop innovative methods for improving the color and texture of the surimi-like gels using water washing and the use of soy whey containing protease inhibitors. Results have been analyzed and reported in three peer-reviewed refereed journals. A tenure-track faculty position on food.
Review Publications
Chang, S., Zhang, Y. 2022. Color and texture of surimi-like gels made of protein isolate extracted from catfish by-products are improved by washing and adding soy whey. Journal of Food Science. 87(7):3057–3070. https://doi.org/10.1111/1750-3841.16229.
Park, S., Chang, S. 2022. Development of recombinase polymerase amplification combined with lateral flow dipstick assay to detect hemolysin gene of Vibrio vulnificus in oysters. Journal of Food Protection. 85(12):1716–1725. https://doi.org/10.4315/JFP-21-455.
