title: Comparison of extracellular DNase- and protease-producing spoilage bacteria isolated from Delaware pond-sourced and retail channel catfish (Ictalurus punctatus).
abstract: BACKGROUND
  Spoilage of fishery products begins immediately following filleting due to microbial growth that degrades fish tissue quality prior to consumption. Extensive research has been conducted to identify such bacterial populations. A better understanding of the mechanisms involved in fish spoilage is necessary as a novel remedy for microbial spoilage inhibition has yet to be established for fish tissue. The present study identified, for the first time, bacterial populations that produce extracellular DNase and protease from Delaware and local retail distributed channel catfish (Ictalurus punctatus) fillets.
  
  
  RESULTS
  A clear trend was identified between bacteria derived from catfish filleted under aseptic conditions where Pseudomonas was the dominant genus. Bacteria isolated from retail catfish contained high quantities of DNase-producing isolates, in contrast to aseptic-filleted catfish tissue which had none. Both types of catfish sample maintained high populations of protease-producing bacterial colonies throughout the duration of the study. Most bacteria isolated from catfish intestines exhibited DNase production with no protease production.
  
  
  CONCLUSIONS
  Specific spoilage organism populations were significantly higher on retail-derived catfish in comparison to lab-filleted Delaware cultured catfish tissue. It is suggested that DNase production and protease production contribute to the spoilage of fish tissue as a result of mishandling and septic filleting being the major cause of rapid catfish tissue spoilage.
authors.affiliation: Department of Human Ecology, Food Science Program, College of Agricultural and Related Sciences, Delaware State University, Dover, DE, 19901, USA.
authors.forename: Michael E
authors.initials: ME
authors.lastname: Hickey
authors.forename: Gina M
authors.initials: GM
authors.lastname: Accumanno
authors.forename: Dennis M
authors.initials: DM
authors.lastname: McIntosh
authors.forename: Grant S
authors.initials: GS
authors.lastname: Blank
authors.forename: Jung-Lim
authors.initials: JL
authors.lastname: Lee
mesh_terms: D000333:Aeromonas / Q000145:classification / Q000201:enzymology* / Q000254:growth & development / Q000302:isolation & purification; D000818:Animals; D001426:Bacterial Proteins / Q000378:metabolism*; D015169:Colony Count, Microbial; D003691:Delaware; D003851:Deoxyribonucleases / Q000378:metabolism*; D005511:Food Handling; D063427:Food Quality; D061353:Food Storage; D007059:Ictaluridae / Q000254:growth & development / Q000382:microbiology*; D007422:Intestines / Q000382:microbiology; D058889:Molecular Typing; D010447:Peptide Hydrolases / Q000378:metabolism*; D010802:Phylogeny; D061005:Ponds; D011549:Pseudomonas / Q000145:classification / Q000201:enzymology* / Q000254:growth & development / Q000302:isolation & purification; D012329:RNA, Bacterial / Q000032:analysis / Q000378:metabolism; D012336:RNA, Ribosomal, 16S / Q000032:analysis / Q000378:metabolism; D012034:Refrigeration; D017747:Seafood / Q000191:economics / Q000382:microbiology*; D012867:Skin / Q000382:microbiology
chemical_list: D001426:Bacterial Proteins; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S; D003851:Deoxyribonucleases; D010447:Peptide Hydrolases
keywords: DNase; catfish; fish spoilage; protease; specific spoilage organisms (SSOs)