Degree

Doctor of Philosophy (PhD)

Department

Renewable Natural Resources

Document Type

Dissertation

Abstract

Shrimp is one of the most consumed and traded seafood, and due to its high demand, consumers depend on both wild caught and farmed products. Post-harvest practices can greatly affect health, safety, and quality, and the goal of this project was to study the effects of chemicals, bacteria, and antibiotics on shrimp from Louisiana and Bangladesh. Quality changes (proximate composition, color, texture and total plate count of bacteria) in shrimp from Louisiana (Farfantepenaeus aztecus and Litopenaeus setiferus) and Bangladesh (Penaeus monodon and Macrobrachium rosenbergii) were determined due to the application of melanosis preventing compounds (sulfite powder, Everfresh® and Xyrex® Prawnfresh™). Sulfite residue in shrimp was determined, and the shrimp were tested for the presence of harmful bacteria. The presence of antimicrobial drugs residue (oxytetracycline, nitrofurantoin, chloramphenicol, fluoroquinolone and malachite green) in aquacultured imported shrimp was also determined. Finally, the soil and shrimp of shrimp farms in Bangladesh were examined for the presence of antimicrobial resistant bacteria. There was no effect of melanosis prevention on proximate composition and total plate count. There was no effect of treatment on color, hardness, resilience and chewiness compared with control shrimp. While sulfite residue was found in shrimp, it was under the FDA limit (less than 100 ppm). However, sulfite was not included in the ingredient list as required by law on any packaging. Vibrio fluvialis was found both in wild caught F. aztecus and L. setiferus, and Pseudomonas luteola was found in F. aztecus. In Bangladesh, Eshcherichia coli, Proteus pennari, Enterobacter aerogenous, Enterobacter cloacae, Enterococcus faecalis, Eshcherichia fergusonii, Serratia marcescens, Enterobacter xiangfangensis and Aeromonas dhakensis were detected from market shrimp. For antibiotic residue tests, out of 42 samples 30 were positive for nitrofurantoin, 1 for malachite green, 1 for oxytetracycline, and 7 for fluoroquinolone. For antibiotic resistant bacteria determination, four species of bacteria were identified: Proteus pennari, Morganella morganii, Enterobacter cloacae and Plesiomonas shigelloides. Some bacterial strains were resistant to chloramphenicol, gentamycin, azithromycin, and vancomycin. Results of this study provided information about how grow out, postharvest handling, and treatment of shrimp affects quality and food safety.

Date

9-19-2018

Committee Chair

Lively, Julie

Available for download on Wednesday, September 17, 2025

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