Commodity levels used

For perishable commodities, the use of modified atmospheres to extend postharvest life and quality of fruit and vegetables has been practised for over 60 years, and the technique is now widely used in combination with lowered temperature and raised humidity. The atmospheres used for storage (up to 10% CO2, < 5% oxygen) include those known to be effective against insect pests, but the low-temperature combination acts against the efficacy of the treatment. For fungistatic action, the addition of 5-10% carbon monoxide to the atmosphere provides protection for commodities that cannot tolerate high C02 levels (Kader and Ke, 1994). 

Becanse of very high consumption of commodities, impnrities at the ppm level can be significant. Unlike specialties, commodities are chemicals of known composition and are sold based on market competition for that material. In many cases, there are specialty versions of commodities, such as specialty sequesterants, used in place of ethylene diamine tetra acetic acid (EDTA) specialty buffers, used in place of canstic or soda ash and specialty bleaches, used in place of hydrogen peroxide. Some of the most common commodities in use in textile operations are shown in Table 7.19. 

Lactic acid has been used in the food, chemical and pharmaceutical industries for years, and has the potential to achieve commodity-level status as an intermediate for oxygenated chemicals, "green" solvents, specialty chemical intermediates, and polylactic acid (PLA). PLA, which is already used in medical devices, holds great promise for increased use as a versatile, environmentally-... 

The bulk chemical commodity producing companies (e.g., refineries, petrochemicals) have been practicing this philosophy for some time, using dynamic models to contain operational variability through feedback controllers, and employing static models to determine the optimal levels of operating conditions (Lasdon and Baker, 1986 Garcia and Prett, 1986). 

This concept was introduced in 1948 by Sondheimer and Kertesz who nsed pH values of 2 and 3.4 for analyses of strawberry jams. Since then, the nse of other pH values has been proposed. Fnleki and Francis (1968) used pH 1 and 4.5 bnffers to measure anthocyanin content in cranberries, and modifications of this techniqne have been applied to a wide range of commodities. The absorbance of anthocy-anins at two different pH levels (1 and 4.5) is measured at Kis-max and at 700 mn, which corrects for haze in the sample (Table 6.3.1). The total monomeric anthocy-... 

Repeatability is defined as precision under conditions where independent test results are obtained with the same method on identical test material in the same laboratory by the same operator using the same equipment within short intervals of time. The replicate analytical portion for testing can be prepared from a common field sample containing incurred residues. This approach is used extremely rarely. Normally, repeatability is estimated by the relative standard deviation ofrecoveries, which should be lower than 20% per commodity and fortification levels according to SANCO/825/00. In justified cases, higher variability can be accepted. 

To reduce the effort, another validation procedure is used for extension of the German multi-residue method to a new analyte. Actually, more than 200 pesticides can be analyzed officially with this method, which is the up-to-date version of the better known method DFG SI9. A typical validation is performed by at least three laboratories, which conduct fortification experiments at the same three levels with at least four representative matrices. These representative matrices are commodities with high water content (e.g., tomato), fruits with high acid content (e.g., lemon), dry crops (e.g., cereals) and commodities with high fat content (e.g., avocado). 

A market basket survey, however, is unique in that untreated control commodities, as the term is normally used in residue studies, cannot be obtained. In a market basket survey, food commodities are collected at the consumer level and not from controlled field tests. By design, the cultural and treatment details for the collected commodities are expected to differ from sample to sample. This factor enables the collected commodities to represent the spectrum of conditions under which crops are supplied for human consumption. 

A second problem was that some lots of control commodities contained one or more extractable interferences, i.e., co-extractives that interfered with one or more of the analytes for the particular commodity and could not be removed during cleanup. This problem was addressed by either using controls from different sources for specific analytes or by blending controls to obtain a matrix with a sufficiently low level of interference to allow accurate determination of recovery. 

The LOD and LOQ were statistically calculated using the data obtained by spiking each matrix (milk, egg, animal tissues, and corn and sorghum raw agricultural commodities) with 0.02mgkg propachlor equivalents. The method s LOD and LOQ for the NIPA were 0.005 and 0.015 mg kg respectively, for both crop and animal tissues. Some fortified matrices had acceptable recoveries at levels below the LOQ. The LLMV was 0.01 and 0.02mgkg for crop and animal commodities, respectively. The LLMV is defined as the lowest fortification level at which acceptable NIPA recovery and precision were demonstrated. 

Generally speaking, the equipment that workers use and the type of agricultural work performed while handling pesticides or pesticide-treated commodities have a major impact on the level of exposure a worker receives. Neat work habits generally lead to lower exposure for agricultural workers who handle pesticides. The current Pesticide Handlers Exposure Database (PHED), which is used to predict exposure to mixers/loaders/applicators, is based on this concept. 

The revealed preference method is an indirect approach that is used in order to monetize use values. This method observes the real choice between money and the environmental goods. Methods often include observations of consumers or producers behaviour or actions, such as the hedonic price method and the production function method. The hedonic price method determines values from actual market transactions. These transactions are used to see how the price of a market commodity varies when a related environmental good changes, such as the effects of noise or air pollution on house prices. The production function method is used to estimate the value of the environmental effects on production. This method is suitable when consumption or production of a private good is affected by the environmental good. An example is the valuation of ground-level ozone levels by valuing the impact on the production of wheat or timber, which has market prices. The problem with the revealed preference method is that it does not contain all the individuals values that affect the WTP. 

Commodity-related models focus on demand volatility and uncertainty in volumes and prices as with sales quantity flexibility. Several authors proposed models to handle demand uncertainty in general focusing on quantities (Cheng et al. 2003 Gupta/Maranas 2003 Cheng et al. 2004 Chen/Lee 2004). Uncertainty is reflected by demand quantity scenarios and/or probabilities. Proposed models maximize expected or robust profit. Process industry-specific models use simulation to address demand uncertainty and to determine optimal inventory levels (Jung et al. 2004). 

The standards and limits adopted by the Codex Alimentarius Commission are intended for formal acceptance by governments in accordance with its general principles. Codex Alimentarius permits only those antioxidants which have been evaluated by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) for use in foods. Antioxidants may be used only in foods standardised by Codex. The antioxidant provisions of Codex Commodity Standards are included in and superseded by the provision of this Standard. Food categories or individual foods where the use of additives are not allowed or are restricted are defined by this Standard. The primary objective of establishing permitted levels of use of antioxidants in various food groups is to ensure that the intake does not exceed the acceptable daily intake (ADI). 

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