Storage periods

It may be debatable for how long it is useful and thus necessary to retain records, samples and specimens from studies, or check-lists from Quality Assurance inspections, whose results may long have been superseded by new data or by simple experience from the use of the test item. 

At the other end of the spectrum of possibilities a complex arrangement could be foreseen in which the supporting documentation for a marketing permit should be retained until, say, five years after the expiry date of the last batch of the product produced anywhere on the world. 

This concession for disposal cannot, however, be read as permission to simply and thoughtlessly destroy study materials. On the contrary, even in this instance the guiding principle of the GLP rules mandates that the final fate of these materials be documented and that, where appropriate, the reasons for the premature disposal have to be provided. Any missing material that should be in the archives, and the fate of which is not documented, would automatically jeopardise the GLP compliance of the test facility Questions about the GLP compliance of either the archive organisation, including the work of the person responsible for the archives, or even the GLP compliance of the whole study touched by this loss would arise. Therefore, the GLP Principles firmly mandate that the final disposition of any study materials should be documented. When samples of test and reference items and specimens are disposed of before the expiry of the required retention period for any reason, this should be justified and documented . 

As one example the case of a bacterial mutagenicity test may be cited, where hundreds of petri dishes with the bacterial colonies grown as a result of the test, and which may be considered to constitute the test system as well as the primary data. After the end of the incubation period these petri dishes cannot be stored for too long a time, since either the bacteria (and any contaminant germs) will continue to grow, or the layer of agar growth medium will dry out, and both of these events will render the plates useless for further evaluation after some time. The petri dishes will therefore have to be discarded shortly after the end of the experiment. The actual raw data of the study to be archived are, however, the bacterial colony counts, whether they have been manually determined or automatically recorded. Thus, if it can be ascertained 

The problem may be considered to become more difficult for specimens and samples which have actually to be regarded as raw data, or where reanalysis might be possible for some time even after the conclusion of the respective study. But on the other hand, there might be clear criteria to determine the end of usefulness of these archived materials. Let us consider the case of the test item sample the archiving of which is mandatory under GLP. At intervals, this sample might be analysed, and at some point of time the analytical chemist will determine that the sample is not useful anymore for its analytical purposes. This assessment will certainly mark the end of its required 

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Containers of foodstuffs should not be unduly stained or etched and must not be perforated or allowed to become distended by pressure due to evolution of hydrogen, and the contents must not suffer unacceptable changes of colour or flavour. Long storage periods, e.g. two years, may be required. 

The strain adapted to pectate showed lag phase by cultivation on this medium corresponding to the first phase of growth on pectin, but after short storage period (two weeks) on malt agar it lost completely the ability to grow on pectate (Fig. 2). There was a possibility to restore this ability to grow on pectate by primary cultivation on pectin. It seems, in conclusion, there is a primary utilization of methanol released from pectin by Candida boidinii and the secondary path, the utilization of D-galacturonate chains, required an... 

Proponents of continuous hypothermic perfusion using colloidal solutions such as cryoprecipitated plasma (Belzer et td., 1972) claim that it provides better immediate life-sustaining function after transplantation. This is probably trae and it oflFers more potential for storage periods of 4 days or more. However, it is technically more diflicult to maintain sterility over such long periods, and its exprense and complexity makes it dependent on the availability of very skilled staff. 

The collected plant samples are analyzed as soon as possible after harvest. When samples or their extracts need to be stored, appropriate storage conditions are imperative. The stability of metabolites should be monitored during the storage period. 

RAC samples from a processing study should be handled exactly as RAC samples from a field residue trial. They should be frozen as soon as possible following collection. Once the processing commodities have been created, they should be frozen and shipped to the analytical lab as quickly as possible. Both the RAC samples and processed samples from a processing study must remain frozen throughout the shipment and storage period of the study in order to preserve residue integrity. 

For suspensions primarily stabilized by a polymeric material, it is important to carefully consider the optimal pH value of the product since certain polymer properties, especially the rheological behavior, can strongly depend on the pH of the system. For example, the viscosity of hydrophilic colloids, such as xanthan gums and colloidal microcrystalline cellulose, is known to be somewhat pH- dependent. Most disperse systems are stable over a pH range of 4-10 but may flocculate under extreme pH conditions. Therefore, each dispersion should be examined for pH stability over an adequate storage period. Any... 

The exergy loss associated with heat infiltration during the three storage periods can be expressed as... 

TES can be achieved by separating the desorption step (charging mode) from the adsorption step (discharging mode). After desorption the adsorbent and the absorbent can theoretically remain in the charged state without any thermal losses due to the storage period until the adsorption process is activated. 

One known disadvantage of direct TES is the fact, that they have to be at a higher (or lower) temperature as the ambience. Due to this temperature difference (their exergy content) the are able to operate as heat (or cold) storage. A thermal insulation is necessary to avoid losses over the storage period. 

Table 16.1 Mean content (mg/g DM) of polyphenols in organically produced Golden Delicious apples in three successive years (analyses were carried out at the beginning of the storage period in December). The percentage differences compared to conventional fruit from the same production unit, the level of significance between conventional and organic fruit ( = P > 0.01 = p > 0.05) or trends (exactp-value listed if 0.05 < p < 0.13) are indicated...

Table 16.3 Standard fruit quality parameters measured at the beginning (December) and towards the end (February) of storage period over three years. Means are of five organic orchards (bio, upper figure) and five conventional orchards (IP, lower figure) working to integrated farming standards ( = P < 0.05)...

Normally only used for further dilution of previously prepared rubber solutions to ensure uniformity. Often used after storage periods for such products as bonding agents to lift deposits from the bottom of delivery and storage drums and to re-establish full dispersion of all the components of the system. 

The effect of storage temperatures on total phenol compounds on strawberry fruit has been also reported (Ayala-Zavala and others 2004). Total phenol compounds increased in berries stored at 5°C and 10°C (Fig. 11.1, II). However, strawberry fruit stored at 0°C maintained a constant value of total phenol compounds during the storage period. Both temperature and storage time had a significant effect on total phenol compounds of strawberry fruits (Ayala-Zavala and others 2004). 

Phenol content (measured as gallic acid equivalents) increased initially in fresh-cut carrot treated with different sanitizers and later decreased in a different pattern for each treatment (Ruiz-Cruz and others 2007). Washing treatments significantly affected phenol content. Comparing sanitized shredded carrots with controls (unwashed and water washed), a sharp increase with a maximum value at days 3 and 6 (5.6 to 6 mg/ 100 g) was found, followed by a decline. Final phenol concentration was 0.7 to 1.3 mg/ 100 g for all treatments at the end of the storage period (Ruiz-Cruz and others 2007). 

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