Influence of handling procedures and biological factors on the QIM evaluation of whole herring (Clupea harengus L.)

QIM evaluations were performed on herring from ten seasonally and geographically distributed cruises and related to handling procedures and biological and chemical parameters. The results showed clear effects from onboard storage methods. The quality of iced herring was superior to the quality of tank stored herring. Off odours developed faster in tank stored herring, and tank storage resulted in more discoloured gills and duller skin than ice storage. Ice storage gave more blood on gill covers. Large spawning herring with high lipid contents had higher quality than small immature herring with low lipid content. The high lipid content was correlated to low scores for all descriptors except blood on gill cover. Blood on gill cover was the only descriptor not dependent on biological or chemical parameters. Some shortcomings were recognised with the QIM scheme. It could differentiate between the quality of iced and tank stored herring, but could not be used to calculate the remaining shelf life. Suggestions are given for modifications of the scheme.