Frozen shelf life

Cut meats may be frozen or kept at chill temperatures. If the latter, the shelf life is comparatively low and the product will be despatched almost immediately for sale. 

The two major leafy crops used for the production of recombinant proteins are tobacco and alfalfa, both of which have high leaf biomass yields in part because they can be cropped several times every year. The main limitation of such crops is that the harvested leaves tend to have a restricted shelf life. The recombinant proteins exist in an aqueous environment and are therefore relatively unstable, which can reduce product yields [16]. For proteins that must be extracted and purified, the leaves need to be dried or frozen for transport, or processed immediately after harvest at the production site. This adds considerably to the processing costs. 

Improper storage of reagents or expired reagents Some antibodies can be aliquoted and frozen to extend their shelf life. 

Red blood cell preparations are usually stored at 2-8°C (although the United States Pharmacopeia includes frozen storage below —65°C). If stored unfrozen, its useful shelf-life must not exceed the shelf-life of the whole blood from which it was derived. If stored frozen, the shelf-life is extended to 3 years (although the product must subsequently be used within 24 h after thawing). 

The qualily of a frozen food may be determined more by the temperature at which it is stored than by the method or rate of freezing. Storage temperatures may fluctuate as products move from manufacturing through distribution channels lo the consumer s home freezer. The useful shelf life or a frozen food may be severely limited by exposure to storage temperatures above - I8 C. even for a few hours. 

Flavor changes that occur in citrus juices are the result of heat input into the product over time i.e., they are a function of temperature and time. It is for this reason that canned and bottled juices are generally less preferred by consumers than other processed citrus juices, e.g., frozen concentrates or chilled juices. The canned juices receive more heat input during pasteurization and they remain at relatively high temperatures for extended periods of time because they are discharged from the water coolers at temperatures near 40°C to facilitate drying and to inhibit rusting of the cans. It is well known that the rate of flavor deterioration increases with temperature, so canned juices are stored at a temperature as low as is economically practical before distribution at the retail level to extend their shelf life as much as possible. 

Packaged as a commercial product, NPVs have a remarkable shelf life. The occluded virions, within the protective inclusion-body protein, are among the most stable entomopathogens, compared with other microorganisms and microparasites, such as bacteria, fungi, protozoa, and nematodes. In the laboratory, lyophilized, frozen, or simply refrigerated NPV inclusion bodies, stored in darkness, remain active for many years, even decades... 

The performance and quality of starch can be improved through chemical modification (see Chapter 17). Chemical modifications provide processed foods, such as frozen, instant, dehydrated, encapsulated and heat-and-serve products, the appropriate texture, quality and shelf life (see Chapter 21), and improved processing condition tolerance, such as improved heat, shear and acid stability. Modification also allows starches to be used in the paper industry (see Chapter 19) as wet-end additives, sizing agents, coating binders, and adhesives and as textile sizes. 

A. R Hansen and F. L. Hemphill, Utilization of heat to increase shelf life of blended acid whey and buttermilk powder for frozen desserts, J. Dairy Sci., 1984, 67, 54—55. 

Shelf Life This term refers to the expected duration of the functional stability of biological substances, including immunochemicals, and most commonly is assessed by experimental tests, statistical work and observation. Within the user s laboratory, periodical comparisons of the working solution with aliquots kept frozen at -20 °C is recommended. The shelf life is terminated by an Expiration Date. 

Several novel methods have been developed over the years to provide one-component systems with long shelf life and good performance properties when cured at a moderate time and low temperatures. These include frozen, microencapsulated, and molecular sieve catalyzed systems. 

For the mAb in this comparison, the initial product is from an early cell line that is formulated as a liquid, stored frozen, and administered by IV injection. This is sufficient for initial safety, PK/PD, and pharmacologic activity assessments in phase 1 but is not an acceptable product profile for commercialization. To be competitive in the intended clinical indication, the product needs to be stored as a lyophilized powder (to increase shelf life and concentration), to be reconstituted and injected SC as needed. The acceptable volume for SC injection dictates a much more concentrated formulation. 

From the snap, gloss and texture of chocolate to the shelf life of frozen foods, crystalline microstructure plays a very important role in the texture, appearance, shelf life and overall quality of many foods. The total amount of crystaUine phase in a food, as well as the size distribution and shape of the crystals within the food, can affect the physical properties of the product. Furthermore, some mataials in food can crystallize in different polymorphic forms so that control of polymorphic transformations may also be necessary. 

Roos, Y.H., Karel, M., and Kokini, J.L. (1996). Glass transitions in low moisture and frozen foods effeets on shelf life and quality. FoodTechnol, 50(11), 95-108. 

Silicate mortars, however, will not be injured by storage in warm locations, with the possible exception of a few with limited shelf life, where it is possible that shelf life may be shortened. But if the liquid component (sodium or potassium silicate) is frozen, the fluid mixture (a colloid) will "break" and the silicate will come out of solution and coat itself on the inside of the metal containers. If this happens, the mortar will not function until the silicate is redissolved— mixed back with solutions using a power-stirring device such as a "Lightning Mixer."... 

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