The effects of different precooling techniques and improved packaging design on fresh fish temperature control

Abstract

The focus of this study was on the effects of different precooling techniques and improved packaging design on fresh fish temperature control. Insufficient temperature control in fresh fish supply chains has negative effects on the quality of fresh fish. It is therefore desirable to cool the product down to its intended storage temperature before packaging using some precooling technique, resulting in an efficient and rapid cooling. The insulation property of the packaging limits heat transfer from the surroundings to the fish. Fresh fish temperature was mapped while exploring different precooling techniques and numerical heat transfer modelling was used to improve expanded polystyrene (EPS) packaging. The precooling experiments resulted in fresh fish temperature profiles which provide guidelines for how to precool fresh fish effectively. The insulation performance of the EPS box was enhanced by increasing the radius of curvature in the corners, thereby increasing material. By these means, the original box was optimised in a 'trial and error' method using numerical heat transfer modelling. Experiments were performed with fresh fish using prototypes and later the new improved box. The result was significantly improved thermal protection during a period of temperature abuse. The conclusion is that by precooling the product to its intended storage temperature and utilising the new improved packaging, the temperature control in fresh fish supply chains can be increased significantly.

Markmið þessa verkefnis var að kanna áhrif mismunandi forkæliaðferða og endurhönnununar pakkninga á hitastýringu ferskra fiskafurða. Ófullnægjandi hitastýring í kælikeðju ferskra fiskafurða frá framleiðanda til kaupanda hefur neikvæð áhrif á gæði afurðanna og því er ákjósanlegt að forkæla fiskafurðir hratt og örugglega niður að geymsluhitastigi fyrir pökkun. Varmaeinangrun pakkninga takmarkar varmaflutning frá umhverfi til vöru. Hitadreifing í fiski var kortlögð fyrir mismunandi forkæliaðferðir og varmaflutningslíkön voru notuð til að endurhanna frauðplastpakkningar (EPS). Niðurstöður forkælitilrauna voru hitaprófílar sem þjóna sem leiðbeiningar að árangursríkri forkælingu. Varmaeinangrun pakkninga var bætt með því að auka bogaradíus í hornum. Þannig var upphaflegi EPS kassinn endurbættur með aðstoð tölvuvæddra varmaflutningslíkana. Tilraunir sem framkvæmdar voru með ferskum fisk með frumgerðum og síðar nýja endurhannaða kassanum sýndu fram á bætta varmaeinangrun. Lokaniðurstöður eru þær að með því að forkæla vöruna niður að geymsluhitastigi og með notkun endurbættra pakkninga er hægt að bæta hitastýringu í kælikeðju fiskafurða töluvert.