VACCUM PACKAGING AND MODIFIED ATMOSPHERE PACKAGING AND STORAGE

VACCUM PACKAGING AND MODIFIED ATMOSPHERE PACKAGING AND STORAGE Ø It is a viable technology in sea food processing. Ø It is wide spread in the meat industry for fresh. Processed and curved products but has faced difficulties in it’s application to sea food. Condition in the vaccum package It is brings several changes 1. A drastic reduction in O 2 content 2. An increase in CO 2 3. Increase in acidity

Advantages: Ø It increase the self life of fish (ie. , It is very good barrier to O 2) Ø Variety of spoilage organisms is substantially decreased Ø Microbial growth is prevented entirely (Partially) Packaging Materials It protects food from environmental contamination and conversely sheids the surroundings from the package contents. In packaging light, water, heat, O 2, bacteria and are consider to be an affecting factors Light The length of the exposure, the wave length and intensity of light and permeability of the package to the light. All affect whether or not nutrients will be destroyed.

Temperature: Ø The type of packaging material greatly affect the rate at which heat ie transferred to and from the food Ø This is important for both refrigerated and frozen sea food Ø Insulating containers like Styrofoam food trays greatly reduce the transfer of heat of the fish, but will retard cooling if the packaged fish is not already very cold. Oxygen Ø Excessive amount of O 2 promote sea food deterioration through the oxidation of fats, the degradation of some amino acids and the destruction of certain vitamins Ø The effects of O 2 are related to the pressure of the environment, the humidity and the temperature. Ø Exposure of the package contents to O may occur through loose closure, puncture and or diffusion through the packaging materials itself.

Permeability to O of some common packaging material Materials Permeability range Silicon rubber over 250, 000 Polyvinyl chloride film, house hold 13000 – 14000 Conventional polyethylene 6000 – 15000 Coated and wax papers 100 – 15000 Cellulose acetate 1000 – 5000 High Density polyethylene 1500 – 3000 Saran 10 - 350 Myler 50 – 100 Permeability also affect by the moisture and temperature

Disadvantages Ø Doesn’t ensure free from microbial activity. Ø The O 2 impermeable materials required are relatively expensive and appropriate equipment is needed Ø Modified atmospheric packaging and storage Ø In 1932, conye reported the beneficial effects of CO 2 in inhibiting the growth of bacteria from fish. Ø The have also been applied to other storage systems, namely CO 2 saturated sea water and CO 2 enriched atmospheres. Ø Increased storage life of fresh fish and shell fish using refrigerated sea water saturated with CO 2

Ø The results appear to apply to a wide variety of species including fatty species of salmon, low fat rock fish and shrimp Ø When the air surrounding the fish is changed in composition usually by enriching it with CO 2 and the container then sealed the atmosphere is called “modified” Ø Fish and shell fish from modified atmosphere storage have lower bacterial counts, greated acidity level, reduced trimethylamine formation and lower NH 3 production. Ø There is also residual and positive effect on the keeping quality after removal from the CO 2 enriched environment. Temp ab use results in bacterial spoilage and possible development of toxins

Ø The accumulation of unpleascent odour in the package and owing to the activity of anaerobic organisms Ø The more serious problem is the threat of C. botulinum activity Ø The odour are not the usual type of “fishy” odours produced by sea food because of the different types of because the circulation of fresh gas removes them.