CAVIAR: ROE PROCESSING MANUAL  

FOREWORD

1.0 CAVIAR PRODUCTS
1.1 INTRODUCTION
1.2 THE WORD 'CAVIAR'
1.3 LABELLING PRODUCTS
1.4 CANADIAN ROE RESOURCES
2.0 ROE
2.1 OVARIES
2.2 MATURITY
2.3 YIELD
2.4 FROZEN ROE
2.5 GRADING FRESHNESS
2.6 CHEMICAL COMPOSITION
2.7 EGG STRUCTURE
3.0 SCREENING
3.1 SCREENING OPERATION
3.2 SCREENING TECHNIQUE
3.3 SCREENING DEVICES
3.4 MECHANIZED SCREENING
4.0 SALTING
4.1 PRESERVATIVE ACTION
4.2 THE SALTING MECHANISM
4.3 SALINITY
4.5 CURING EFFECT
4.6 SALTING TIME
4.7 SALINITY MEASUREMENTS
4.8 DRAINING, EGG VISCOSITY AND VISCOSITY MEASUREMENTS
5.0 PACKING
5.1 FREEZING AND REFRIGERATION
5.2 BULK AND RETAIL PACKAGE
5.3 PACKAGE TYPE
5.4 CHEMICAL PRESERVATION
5.5 ADDITIVES AND DYES
5.6 PASTEURIZATION
5.7 PACKAGING OVERVIEW
6.0 QUALITY AND SHELF-LIFE
6.1 QUALITY GRADING
6.2 ORGANOLEPTIC TRIALS
6.3 DEFECTS
6.4 CHEMICAL AND BACTERIOLOGICAL EXAMINATIONS
6.5 SHELF-LIFE
6.6 QUALITY CONTROL AND ASSURANCE
7.0 THE CAVIAR SHOP
7.1 LAYOUT AND MECHANIZATION
7.2 PLANNING A SALMON CAVIAR OPERATION
7.3 WATER QUALITY
7.4 SALT QUALITY
7.5 BRINE PROPERTIES
7.6 BRINE MAKING REQUIREMENTS AND APPARATUS
7.7 SALTING TANKS
7.8 MISCELLANEOUS TOOLS, INSTRUMENTS AND MECHANISMS
7.9 SANITATION
8.0 PROCESSING DIFFERENT SPECIES
8.1 HARVESTING LUMPFISH ROE
8.2 PROCESSING LUMPFISH CAVIAR
8.3 WHITEFISH AND OTHER ORDINARY FISH
8.4 STURGEON FISHERIES
8.5 PROCESSING STURGEON CAVIAR
8.6 SALMON FISHERIES
8.7 PROCESSING SALMON CAVIAR
8.8 ARTIFICIAL CAVIARS

8.0 PROCESSING DIFFERENT SPECIES

8.1 HARVESTING LUMPFISH ROE

Lumpfish caviar technology described in this chapter may serve in many respects as a guideline for processing other small size roes like carp, bream, roach, pike, and white-fish.

Lumpfish fishing history started in the fifties as a small boat coastal water fishery of fish congregating for spawning. Only the fish roe is used as raw material for lumpfish cav-iar. It is one of the most popular sturgeon-caviar substitutes. Attempts to make use of the fish carcasses for bait, for meal or for human consumption have not enjoyed com-mercial success. Fresh lumpfish fillets have found some limited use in Iceland as an ex-otic specialty product. High water content and low protein yield makes lumpfish an ex-pensive resource for fishmeal production. Experiments to substitute lumpfish for herring in lobster traps and for ground fish long lines were not successful. As a result millions of pounds of lumpfish carcasses are discarded annually over shallow water, which are often fishing grounds for crustaceans.

Initially, lumpfish were extensively harvested only in European waters. With the de-mand growing the lumpfish fisheries have expanded throughout the Atlantic.

Our knowledge of the biology of lumpfish and information on the strength of stocks are insufficient to make long-term projections regarding the sustainability of lumpfish fish-eries. Figure 8-1 shows world catches by countries. The information compiled by Mr. E. Olafsson (Iceland) shows a maximum production of over 6,000 tons of roes in 1987. The yearly fluctuations reflect the demand-supply pressures in the marketplace. Biologists speculate that a 10/000 ton sustainable world roe harvest is viable.

Figure 8-1

World Production of Lumpfish Roe 1971-90, Thousand tons

In the seventies Denmark was buying up to 60% and Germany up to 25% of the total world production of heavy salted lumpfish roe. Through the eighties this share fell to 25 and 5%. France, USA and other countries are packing from 2 to 10% of the world's pro-duction. At the same time Iceland's share of packed lumpfish caviar production grew from 5% in 1970 to 60% in 1990. Canada's lumpfish caviar production is only emerging in spite of the fact that Canada is the second largest Lumpfish roe producer.

Lumpfish are harvested by gill nets which are placed in fish migration pathways to the spawning ground. The smaller males often pass through the large mesh. Because of their peculiar morphology the fish are not strongly enmeshed, so fishermen pull the nets care-fully so as not to lose the catch. Fishing depth varies and may exceed 50 meters. Nets are set at the bottom in fleets of five to ten nets each up to 100 meters long. Net depth ('width') measures 10 to 16 meshes of 11 inch mesh size.

Net fleets are moored with anchors and are checked at least every other day. The entan-gled fish is usually alive. Ovaries from dead fish are not used.. When using a gaff to pull the fish, care must be taken not to damage the roe. The roe constitutes 15 to 30% of the total fish body weight, which ranges from 2 to 7 kg. Fish length is 35 to 60 cm.

The schools contain different year classes, which is difficult to determine. It is observed that spawning takes place over the same grounds in waves. The peak period of maturity differs greatly from area to area and depends on water temperature. Knowledge of the behavioral patterns of spawning schools is essential for obtaining best egg yields. Fish-ing grounds are dispersed along a lengthy shoreline, which creates difficulties for the processing logistics. Many fishermen, finding it difficult to quickly transport fresh roe to larger processing sites, are screening and heavily salting roe themselves. That is one of the reasons why processing low salted caviar from fresh roe on the fishing grounds is not yet widely implemented.

Ovaries are extracted as soon as the fish is onboard. Slits are done from the tail end up-ward, leaving the anal end intact. Unlike salmon ovaries, the lumpfish ovaries attach-ment to the body is not strong enough to hold them when the fish is held up vertically by the tail.

Ovaries are removed and first put into a flat mesh basket to get rid of the excessive fluid released from the belly cavity. Then any organs which are still attached to the ovaries are manually removed and the ovary is put in a clean transportation container.

Containers should have a lid, be kept cool, and provide for continuous drainage of ex-cessive fluid. Direct contact of ovaries with ice is not recommended. Ovaries are trans-ported in layers not exceeding 30 cm to reduce transportation stress. Stackable shallow boxes with lids are preferred. Some grading by size and colour is advisable as the ova-ries removed. Mature eggs are purple to reddish, immature eggs range from green to grey.

As soon as possible, in any case, within 24 hours, the chilled ovaries are screened in on-shore facilities manually, or using machines. Screening of ovaries at high tempera-tures, screening immature ovaries, or non fresh ovaries results in excessive breakage and lower yields.

The eggs inside the ovaries are essentially sterile. This means, that if they are not dam-aged during extraction and quickly rinsed before screening in light (3 to 4%) brine to wash off slime and residuals of blood, the lowest possible contamination with microor-ganisms is achieved.

Exposure of ovaries to direct sunlight causes substantial quality losses. Fresh ovaries are elastic. Deteriorated ovaries become soft and the eggs are easily squashed releasing milky egg yolk. Final grading before screening is important to keep separate lots of dif-ferent quality.

Overmature lumpfish eggs are said to have a thin outer membrane. This may be of great advantage in obtaining the "melting" mouthfeel, similar to the one of sturgeon eggs. Roe of this quality should be slightly salted and packed for consumption without preliminary heavy salting. Combined with grading by size and colour and dying in grayish shades such a product may claim premium quality.