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Bulking, Shelfing or Boxing?

Accompanying Notes
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MINISTRY OF AGRICULTURE, FISHERIES AND FOOD

TORRY RESEARCH STATION

By J. J. WATERMAN

TORRY ADVISORY NOTE No. 15 (Revised)

This advisory note discusses the relative merits of the three most common methods of stowage for chilled white fish on board trawlers. The information is intended to serve as a guide not only for trawler owners and their crews, but also for merchants who want to know more about current stowage practice.

Each of the three methods depends for its satisfactory use upon the intimate mixture of fish and ice in order to cool the catch rapidly and to keep it cool. Incorrect stowage can in each case increase the likelihood of landing poor quality fish; correct and incorrect application of each method is described and the advantages and limitations of the methods are discussed.

White fish, such as cod and haddock, if gutted, washed and properly stowed in shallow layers, thoroughly intermixed with ice very soon after catching, will remain in first class condition for about five days and remain edible for about fifteen days. Halibut and plaice will keep a little longer, whiting not quite so well.

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Accompanying Notes

Discusses the relative merits of three methods of stowing chilled white fish on trawlers, i.e. bulking, shelfing and boxing. Describes the correct and incorrect application and the advantages and limitations of each method and draws attention to the lack of implementation of good practice in the industry. Concludes that boxing at sea, properly carried out using suitable boxes and sufficient ice, can produce better quality fish at landing than either of the other two methods, and can help to ensure that the fish deteriorate as little as possible after landing. Lists some of the basic design requirements for a satisfactory fish box for use at sea. Reference is made to 'stinkers'; also called 'bilgy' fish. In the context of this Note, these are fish that emit a foul smell unusually early during chilled storage as a result of being laid close against a smooth surface, thus excluding air from an area of skin and encouraging rapid growth of anaerobic spoilage bacteria. The term stinker is also used in the trade to describe fish, especially cod, that have an unpleasant intrinsic paraffin-like odour and sulphide flavour when caught. They are often described as 'weedy', due to the presence of dimethyl sulphide, produced as a result of feeding on planktonic, gastropod molluscs called pteropods (Spiratella retroversa); also called 'blackberry' cod. Reference is also made to 'kit', a measure of weight for the sale of white fish on the quayside (Note 17).

To meet current hygiene requirements, boxing in plastic boxes of nest/stack and stack only types, of varying dimensions and nominal capacities, is the norm. The 70 litre plastic box with a nominal capacity of 45 kg fish plus ice is widely used, but other sizes are also in use. The capacity of the unit box should not be used as an accurate indicator of the quantity of fish actually present in the box on landing. It has been common practice to overfill these plastic boxes by up to 40% compared with the nominal capacity. Unfortunately, overfilling of boxes with fish, and the consequent loss of weight and quality of the fish compared with correct boxing practice, remains a problem for the industry to resolve. See also Note 21.

Table of Contents

BULKING
SHELFING
BOXING
BULKING, SHELFING OR BOXING?

Contents   Index