Color contamination control

Uses Solubilizer, hydrotrope for cleaners, contaminant control in pulp and paper Features Low foaming, highly effective in high pH formulations Properties CL, pale yel. liq. Gardner color 3 max. sol. in water insol. in polar and aromatic soivs. dens. 1.2 pour pt. < 0 C flash pt. > 100 C cloud pt. (4% in 9.3 N NaOHG) 40-65 C pH (as is) 8-10 50% act. 

Uses Detergent, emulsifier, solubilizer, wetting agent for cleaners, polyacrylamide emulsions, contaminant control In water treatmenL pulp and paper FhoperSes Cl. liq. color APHA 50 max. cloud pt. (1% sol n) 90-100C pH (5% sol n) 6-8... 

Chelate Formation. Citric acid complexes with many multivalent metal ions to form chelates (9,10). This important chemical property makes citric acid and citrates useful in controlling metal contamination that can affect the color, stabiUty, or appearance of a product or the efficiency of a process. 

Orga.nic Colora.nts. The importance of coal-tar colorants cannot be overemphasized. The cosmetic industry, in cooperation with the FDA, has spent a great deal of time and money in efforts to estabUsh the safety of these dyes (see Colorants for food, drugs, cosmetics, and medical devices). Contamination, especially by heavy metals, and other impurities arising from the synthesis of permitted dyes are stricdy controlled. Despite this effort, the number of usable organic dyes and of pigments derived from them has been drastically curtailed by regulatory action. 

Chemical contaminants are usually not reduced or removed by processing steps. Chemical risks must preferably be controlled as early as possible in the agri-food chain. Food color additives (Section 7.1.3) are chemical compounds and are considered potential risks. Therefore a safety evaluation is part of the approval of a food colorant before its use is acknowledged by legislation (see also Section 7.1.6). This section explains the principles of risk assessment and includes an example of such an assessment of a specific food colorant. 

In both research and practice, critical localised concentrations of metal contamination can be difficult to detect. Potassium hexacyanoferrate(II) (10.80) gives an intense deep blue coloration with iron(III), permitting extremely sensitive detection of tiny iron spots even by visual inspection. It is recommended as a quality control measure on batches of cotton destined for bleaching [237]. However, in view of the random distribution of metal traces, even the most sensitive test cannot guarantee freedom from contamination throughout a batch of goods to be bleached. 

The tolerance to high pHs is important in particular for industrial processes using reactive azo dyes, which are usually performed under alkaline conditions. A strain of C. bifermentans selected from a contaminated soil was tested for the ability to decolorize Reactive Red 3B-A at pHs from 5 to 12 while no decolorization was observed at pH 5, the dye was nearly completely decolorized across a broad range of pH values (6-12) after 48 h of incubation in this study a previous analysis of UV/Vis spectra of Reactive Red 3B-A, Reactive Black 5, and Reactive Yellow 3G-P after 0, 12, 24, and 36 h incubation was carried out, showing different decolorization rates for the three dyes, with no change in color content in the abiotic control [5]. 

Postharvest approaches include control of moisture and temperature and proper ventilation. Treatment of contaminated corn with 2% ammonia reduces aflatoxin levels (Park et al., 1988), however this treatment changes the nutritional value of the seed and causes an ammonia odor and a change in color. Ammoniation is not an FDA-approved detoxifying procedure for crops intended for interstate commerce - it can be used only for crops to be used within the confines of a farm. Furthermore, ammoniation is a hazardous procedure for those conducting treatment. 

We have described a process by which small quantities of foam can be made by the prepolymer method. A number of methods are available to bring the variables involved in prepolymer making under control. We assume that the starting point for such processes is the acquisition of commercial isocyanates, polyols, and additives. Other than for audit purposes, we will assume they arrive with certification that they are of the so-called urethane grade. In the case of polyols, this typically means they contain less than 0.01% water and have good color. Free acids and low metal and chloride contents are important considerations for isocyanates. Manufacturers are well aware of the problems that will arise if these contaminants are not controlled and the materials cannot be used with confidence. 

The plastics industry is mainly concerned with the Bureau of Foods which conducts research and develops standards on the composition, quality, nutrition, and safety of foods, food additives, colors and cosmetics, and conducts research designed to improve the detection, prevention, and control of contamination. The FDA is concerned about indirect additives. Indirect additives are those substances capable of migrating into food from contacting plastic materials. Extensive tests are carried out by the FDA before issuing safety clearance to any plastic... 

This test is designed to limit the content of common metallic impurities colored by sulfide ion (Ag, As, Bi, Cd, Cu, Hg, Pb, Sb, Sn) by comparing the color with a standard containing lead (Pb) ion under the specified test conditions. It demonstrates that the test substance is not grossly contaminated by such heavy metals, and within the precision of the test, that it does not exceed the Heavy Metals limit given as determined by concomitant visual comparison with a control solution. In... 

Plasticizers, antioxidants, and colorants are all potential contaminants of foods that are contained in plastics made with these chemicals. Control of potential migration of plastic components requires testing the containers with food simulants selected to yield information relevant to the intended type of food to be packaged (DeKruyf et al. 1983 Bieber etal. 1984). 

Deodorization/Physical Refining Quality control is especially concerned with flavor, free fatty acid concentration, color, stability, and trace contaminants. With respect to routine flavor testing, two-three trained panelists test the flavor of small sample of the oil. The oil must be essentially bland, but very slight beany or grassy notes are tolerated. Free fatty acids, color, and stability testing is done by the AOCS official methods (76). 

---