Storage freezer

To fortify a sample, the label from a fortification sampling vial was removed and secured to the pre-labeled sample jar. Spike vials were individually shaken before use. The cap was discarded, the contents of the vial were poured into the sample jar and then the vial was dropped into the sample. The sample jar was capped with a Tefion-lined lid, hand shaken to mix, placed in a Kapak bag and sealed. Jars were placed immediately in storage freezers. In all cases, quality control samples were transported and stored with their corresponding field plot samples throughout sample handling and shipment to the analytical facility. 

Sample storage freezers located at the Research Farms and those of the Residue laboratories are considered to be limited access archives and are kept locked. Access is limited to the sample preparation laboratory employees. All movements of samples in and out of the freezers are recorded. One freezer in the Residue Laboratory... 

The field investigator s residue sample handling procedures and equipment are always inspected. It is policy that samples be held at the field locations for only short periods however, accurate records are kept on the storage and handling conditions from the time a sample is collected until it is shipped to the laboratory. The elapsed time from collection until a sample is placed in a freezer must be recorded as well as the location of the freezer and the temperature of the freezer during the storage. The sample storage freezer and the records kept on it are always inspected. 

Most >-xylene is available commercially at a purity less than 99.9 % and can be purified by recrystallization. To prepare 1.9 L of high purity p-xylene, begin with approximately 3.8 L of material and cool in a flammable storage freezer at -10 5 C until approximately A to V4 of the p-xylene has frozen. This should require about 5 h. Remove the sample and decant the liquid portion. The solid portion is the purified p-xylene. Allow the p-xylene to thaw and repeat the crystallization procedure on the remaining sample until the p-xylene is flee of contamination as indicated by gas chromatography. 

Containerized ice cream is hardened on a stationary or continuous refrigerated plate-contact hardener or by convection air blast as the product is carried on a conveyor or through a tunnel. Air temperatures for hardening are —40 to —50° C. The temperature at the center of the container as well as the storage temperature should be <—26°C. Approximately one-half of the heat is removed at the freezer and the remainder in the hardening process. 

Frozen Egg Products. Frozen egg products include egg white, plain whole egg, whole egg with yolk added (ie, fortified), plain egg yolk, fortified whole egg with com symp, sugared egg yolk, salted egg yolk, salted whole egg, and scrambled eggs and omelets. Egg products are frozen in a blast freezer at —40 C for up to 72 h, and then held for storage at —24 C (see Refrigeration and refrigerants). They are used by large and small bakeries and for other uses. 

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. 

The ice-cream is still plastic as it comes from the freezer, and it is extruded into the final sales shape - carton, tub, box, etc. It must then be hardened by cooling down to a storage temperature of - 25°C or lower, during which the other half of its heat of freezing is removed. 

The aldehyde contains small amounts of the starting ester and the overreduced alcohol along with other minor impurities. It can be stored for short periods of time (1-2 days) in a freezer at -20°C without significant deterioration. However long term storage is not recommended. 

Samples collected from the field should ideally be placed in boxes in order to prevent damage to the crop sample and to aid storage, although this often depends on the freezing facilities of the organization concerned. Where samples are boxed, untreated samples should not be mixed with treated samples. When freezing, samples should be separated by space or by using separate freezers for treated and untreated samples. 

Sample transportation logistics Freezer storage sample processing j capabilities... 

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