Location: Warmwater Aquaculture Research Unit
2022 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 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 investigate the inactivation of bacteria in oysters produced by an oyster aquaculture farm in Alabama by using hydrostatic pressure up to 600 mPa and timed 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 PCR method. Results from our 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. 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. Enhancing the safety and quality of oyster meat using high hydrostatic pressure processing (HPP). High hydrostatic pressure processing is one of the four FDA-approved post-harvest processing technology for reducing the risk of eating raw oysters. The effect of HPP processing technology on the oysters produced in the Northern Gulf region had not been comprehensively studied. The objective of this research was for ARS researchers in Stoneville, Mississippi, to search for the best HPP conditions for processing oysters over a wide range of pressures and processing time intervals. Our completed results have identified the range of the conditions that could facilitate shucking and to reduce pathogens and to enhance shucking efficiency as well as to increase meat yield. The results can be transferred to preserve the natural quality of oysters with improved safety and to enhance marketing raw oysters to the consumers.
2. Development of a rapid, sensitive, and equipment-free detection of Vibrio vulnificus in oysters. Vibrio vulnificus in oysters and in beach water is very hazardous to human health since it can cause the death of people with physical wound infected by this pathogen. The official method approved by FDA and NSSP (the National Shellfish Sanitation Program) for Vibrio vulnificus analysis uses culturing method and followed by gene hybridization, and would take 4-5 days to complete. ARS researchers' in Stoneville, Mississippi, objective was to develop a rapid, sensitive and equipment-free method for the detection of this pathogen. Our completed results confirmed that the test could be done in 30 min. This method will have broad applications in the seafood industries, and will be useful for government agencies for making decisions for beach closure, when this pathogen is detected in the beach water.
3. Optimizing efficiency of protein extraction from catfish by-products, containing heads and frames. Catfish by-products (skin, heads and bones), which account for more than 200 million pounds each year and almost 40-50% of the total fish proteins, have been considered as a waste for a long time. ARS researchers' in Stoneville, Mississippi, objective was to enhance the recovery of proteins and improve its quality through understanding of the protein structures. Our results showed that protein product’s functional performance, such as color could be improved by repeated washing. In addition, the texture profile of the surimi-gels could be improved by the use of soy whey to control the protein degradation during cooking. The engineering data obtained will pave the foundation to contribute to making of successful fish products that are acceptable to the consumers.
4. Recent findings showed that such gradual exposure to sublethal concentrations of biocides (sanitizers) could co-select for bacterial cells that are tolerant to lethal concentrations of biocides. Therefore, ARS researchers' in Stoneville, Mississippi, objective was to understand the role of sublethal concentrations of biocides in the emergence of heterologous stress-response in L. monocytogenes and if it would lead to the antibiotic tolerance/resistance development. In this project, we tested three approaches for continuous exposure to sublethal concentrations of QAC against actively growing planktonic cells of L. monocytogenes and evaluated the subsequent changes in antibiotic susceptibility against trimethoprim by three different methods. Our findings showed that there was a development of low-level tolerance to trimethoprim in L. monocytogenes strains after exposure to sublethal concentrations of QAC. These findings are useful in identifying the predisposing conditions for slow emergence of fluoroquinolone-resistant strains of L. monocytogenes, which may create food safety risk. The findings also can contribute to the development of early detection methods for detecting Listeria monocytogenes in the future.
Review Publications
Kode, D., Nannapaneni, R., Chang, S. 2021. Low-level tolerance to antibiotic trimethoprim in QAC-adapted subpopulations of Listeria monocytogenes. Food and Agricultural Immunology. https://doi.org/10.3390/foods10081800.
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. 10.1111/1750-3841.16229.
Shang, S., Zhang, Y. 2021. Trypsin inhibitor activity, phenolic content and antioxidant capacity of soymilk as affected by grinding temperatures, heating methods and soybean varieties. LWT - Food Science and Technology. 153:112424. https://doi.org/10.1016/j.lwt.2021.112424.
Chang, S., Yang, Y., Zhang, Y. 2022. Determination of protease inhibitors, glycinin and beta-conglycinin in soybeans and their relationships. Journal of Food Science. 87:1082-1095. https://doi.org/10.1111/1750-3841.16054.
Lin, C., Lee, Y., Kung, H., Cheng, Q., Qu, T., Chang, S.K., Tsai, Y. 2021. Inactivation of microbial loads and retardation of quality loss in Asian hard clam (Meretrix lusoria) using high-hydrostatic-pressure processing during refrigerated storage. Food Control. 133(Part A):108583. https://doi.org/10.1016/j.foodcont.2021.108583.
Tsai, Y., Kung, H., Lin, C., Hwang, C., Liu, S., Huang, C., Chang, S.K., Lee, Y. 2022. Combined effect of brine salting and high-hydrostatic-pressure processing to improve the microbial quality and physicochemical properties of milkfish fillet. International Journal of Food Properties. 25:872-884. https://doi.org/10.1080/10942912.2022.2066120.
Chen, D.M., Moore, M., Willis, E.L., Kouba, A.J., Vance, C.K. 2022. The impact of time and environmental factors on the mitochondrial vesicle and subsequent motility of amphibian sperm. Comparative Biochemistry and Physiology - Part A: Molecular & Integrative Physiology. 268:111191. https://doi.org/10.1016/j.cbpa.2022.111191.
Santos-Rivera, M., Woolums, A.R., Thoreson, M., Meyer, F., Vance, C.K. 2022. Bovine respiratory syncytial Virus (BRSV) infection detected in exhaled breath condensate of dairy calves by near-infrared aquaphotomics. Molecules. 27(2):549-562. https://doi.org/10.3390/molecules27020549.
