Blast freezing

As a general rule, any product which will be eaten without cooking, or only very brief cooking (such as green peas), should be quick-frozen in a blast-freezing tunnel or similar device. Other foodstuffs need not be frozen so quickly, and may be left in a coldroom at a suitable temperature until frozen. 

Commodity Liquid freon Liquid nitrogen Blast freezing... 

Blast freezing via forced air and/or sprayed liquid nitrogen. 

Poultry may be chilled for the fresh chicken market, or frozen. Chilling and freezing are mainly by cold air blast. Large birds such as turkeys are wrapped and immersed in low-temperature brine until the outside is well frozen, and then put into low-temperature storage to freeze right through. Some poultry is frozen by spraying with liquid carbon dioxide. 

Most vessels can now freeze their catch at sea, enabling them to stay offshore without the need to run back to a port within the limited life of the chilled product. If the fish is to be cleaned and processed later, it is frozen whole, either by air blast or, more usually, in vertical plate freezers (see Figure 1.9b), followed by frozen storage. Some fishing vessels and the fish factory vessels will carryout cleaning, filleting and other operations on board and then freeze and store the final product. 

Continuous, plate and air blast freezers for ice-cream Low-temperature brine for lollipop freezing... 

Material to be frozen can be fully immersed in a cold liquid. This might be a brine, in which case the material may have to be wrapped in a plastic bag to avoid contact with the liquid. The sodium chloride and glycol brines cannot be used cold enough to get complete freezing, so this may be a first pre-cooling stage before a final air blast. Alternatively, liquid nitrogen (- 196°C) or carbon dioxide (-78.5°C) can be sprayed onto the surface. 

In areas notsubjectto freezing, fire, mechanical damage, or blast damage, aboveground piping is acceptable. Mains should be kept outside of areas... 

Nagaoka, ]., Takagi, S. and Hotani, S., Experiments on the freezing of fish in an air-blast freezer, Proc. Int. Congr. Refrig., 2 (1955) 4. 

Potassium nitrate is used in explosives, blasting powders, gunpowder, matches, and fireworks. Other applications of this salt include pickling meats tempering steel impregnating candle wicks freezing mixtures preparing other potassium salts and as a diuretic. 

Frozen Blasting Gelatin. Blasting Gelatin (See Vol 2, p B211-R) exists as a yellowish translucent, elastic mass of density about 1.63. It is very difficult to freeze. When frozen, it loses its elasticity and flexibility, and becomes a hard white mass. Unlike Guhr Dynamite and Straight Dynamite, it is more sensitive to shock when frozen than when in a soft and unfrozen state Refs 1) Naoum, NG (1928), 311-12 2) Davis (1943), 343... 

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