Location: Warmwater Aquaculture Research Unit2017 Annual Report
1a. Objectives (from AD-416):
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.
1b. Approach (from AD-416):
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.
3. Progress Report:
All Objectives were planned and completed by the ARS scientists in Stoneville, Mississippi, in collaboration with the scientists in the Mississippi State University. Progress was made on all three objectives and their sub-objectives, all of which have a major focus on the ensuring the food safety of catfish, seafood and produce. 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. X-ray irradiation was used successfully to reduce bacterial pathogens and norovirus in oysters and seafood, such finfish products used in sushi products, and in selected freshly cut fruits. Various sanitation methods using acids, alkali, low-temperature and oxidative agents used in reducing pathogens such as Salmonella and Listeria. Progress was made on the understanding of the development of cross-resistance of the sub-lethal concentrations of the sanitation agents, and the use of antibiotics. This is important for future development of intervention methods for controlling pathogens in during food processing and storage. Objective 2: Significant progress was made to understand the mechanisms influencing microbial survival of selected pathogens in seafood/aquaculture products. Progress has been made to identify the molecular differences between virulent (high-risk) and non-virulent (low-risk) pathogens. Novel detection methods were invented to detect pathogens in a rapid and less costly manner. The specific genetic factors, which were related to pathogen’s adhesive ability to attach on the surface of the equipment of food processing, were identified. Progress was made to develop the methods for detection of toxins that could be present in catfish under certain environmental conditions. Progress was made on the development of chemical polymers from agricultural waste (fiber from cotton stalk) and seafood waste (chitin from shrimp shells) to reduce pathogens and heavy metals in fish ponds. Objective 3: Through the collaboration with the USDA-ARS Southern Regional Research Center, progress was made on the extraction of useful proteins for making useful products from catfish by-products (such as heads, frames and skin) after filleting and from the invasive species of carps (silver carp) and the quality characteristics of the protein products were characterized. Progress was also made on the understanding of environment temperature and oxygen content of the water in the pond on the color of the fish fillet. This would lead to enhancement of the fillet quality for marketing.
1. Utilization of the invasive carp species for surimi products. Invasive carps are undesirable for the ecology of the Mississippi River and its tributary water. Utilization of the carp meat as a food protein source for surimi products will contribute to the elimination of carps from the river. ARS researchers in Stoneville, Mississippi, showed that the surimi made from carp meat is very firm. Different types of starch was used to reduce the firmness making the gel more palatable and whiter. The cooking loss of surimi gel containing 6% starch was significantly lower than the control without adding starch when modified starches were applied. Fish sauce was successfully produced from the frame and offal of silver carp by fermentation. The research provides technology for further improvement of the quality of food made from carp, and will allow the food industry to adopt the technology for productive use of this invasive species.
2. Value-added utilization of catfish by-product from the fillet processing industries. In the fillet industry, approximately 55% of the catfish are the by-product, that amount to be more one-hundred million pounds per year in the state of Mississippi alone. The by-product contains significant amount of proteins. The by-products need to be processed or disposed otherwise will cause environmental problem. The results obtained by ARS researchers in Stoneville, Mississippi, showed that protein recoveries form heads, frames, and skins exceeded 50% of that in the raw materials. The by-product has little value and was considered as processing waste. Better laboratory scale extraction of gelatin from fish skins was developed. The findings were presented to the scientists and industry representatives in the annual meetings of the Institute of the Food Technologists. A national competitive grant proposal was resubmitted to USDA-NIFA (National Institute of Food and Agriculture) for consideration. The review was favorable and in the medium funding priority. A revised proposal, including mathematical prediction modelling for predicting product quality and more economic feasibility study was submitted again for consideration. The preliminary studies done on this project will lay the foundation for commercial production of protein products in the future. The impact is in terms of millions of dollars and creation of many jobs for Mississippi and the region.
3. Analysis of allergens in peanut varieties and assessment of effects of food processing on peanut allergens. Peanut allergy is one of the most common causes of food related death. Peanut allergy is typically life-long and the number of people with peanut allergies in developed countries, including the United States, appears to be increasing. Despite the seriousness of peanut allergy, to date, there is no cure for peanut allergy. Currently the only available treatment is complete peanut avoidance. However, avoiding peanuts in food product is difficult because of its ubiquitous use as an ingredient in processed foods. Thus, production of a peanut that has reduced levels of allergens will benefit consumers who suffer from peanut allergies. To this end, scientists at Mississippi State University have analyzed 122 peanut varieties and found that eight peanut varieties have reduced levels of major allergen. ARS researchers at the Mississippi State University, Mississippi, in collaboration with ARS researchers in New Orleans, Louisiana, also found that frying peanut seeds for eight minutes could reduce the level of a major allergen. This information can help growers to choose peanut varieties with reduced allergen levels and inform food industries about the useful peanut processing method for reducing allergen levels. The results will benefit consumers greatly.
4. Reducing arsenic content in rice through genetic and food processing research. Arsenic is a toxic heavy metal that tends to accumulate in rice. Fish and rice grown in arsenic contaminated water will have increased levels of arsenic. Consumption of food with a high heavy metal would damage consumers’ health. ARS researchers at Mississippi State University, Mississippi, in collaboration with ARS researchers located in Stuttgart, Arkansas, have identified the high and low arsenic rice germplasm. Excellent germplasm lines were collected worldwide and grown in Starkville, Mississippi. The arsenic contents of selected key germplasm lines were detected and verified. Crosses were made for mapping population construction. A novel procedure to reduce rice arsenic content was established. The method can substantially reduce arsenic and lead content in cooked rice, but have very minor effect on other minerals. The exciting results suggest that continuing the research may substantially contribute to reducing human arsenic exposure from rice consumption.
5. Reducing aflatoxin contamination in corn production using resistant lines. Corn is frequently infected by a soil fungal pathogen Aspergillus flavus in the pre-harvest and post-harvest stages. Infected corn by A. flavus can produce aflatoxins B1 and B2, and ingestion of corn contaminated with aflatoxins causes liver damages and suppresses the immune systems. One of the strategies in reducing aflatoxin contamination is to breed maize lines with resistance to the fungus. With the collaboration of scientists in USDA-ARS in Starkville, Mississippi, scientists in the Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology at Mississippi State University have tested genes encoding small ribonucleic acid (RNA) molecules in resistant maize plants that may be involved in resistance to aflatoxin accumulation. This study facilitates our understanding of the molecular mechanisms governing maize resistance to the fungus and aflatoxin accumulation. The goals of this research are to reduce the loss to aflatoxin contamination of corn and eliminate an important food and feed safety problem.
6. Development of a rapid detection system for pathogenic Burkholderia spp. A certain species of pathogenic Burkholderia bacteria is associated with soil and water where vegetables and fish are grown and if transmitted to humans can caused illness. However, no method is available for detection of pathogenic Burkholderia from fresh vegetables and catfish. Isolated from Fresh vegetable and catfish, ARS researchers at Mississippi State University, Mississippi and ARS researchers in Auburn, Alabama, have isolated from vegetables and catfish 88 sequenced genomes or genome drafts of the Burkholderia strains in the National Center for Biotechnology Information GenBank to identify unique regions for the genes. They have identified one pair of gene primers that produces a unique gene product from the one specific Burkhoderia that is not in the rest of bacterial tested. From 45 samples collected from the local grocery stores, which included lettuce, cucumber, cabbage, celery, onion, and catfish, two specific bacterial isolates of B. contaminans were recovered from the samples sweet onion and celery stalk. In addition, some animal and human pathogens, such as Brucella species was recovered from a celery stalk. The results were significant for future development of a sensitive method for detecting pathogenic Burkhoderia that will lead to the reduction in human illness, particularly in consuming uncooked vegetables.
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