Quality control principles

The reliability of measurements plays a pivotal role in food and agricultural areas, particularly in the case of undesirable toxic compounds such as mycotoxins. Quality-control principles for mycotoxin analysis are common to other trace analyses, so good laboratory practices, such as EN 4500, represent the heart of quality assurance requirements. Harmonized Guidelines for Internal Quality Control in Analytical Chemistry Laboratories, published by IUPAC (23), also presents valuable guidelines for the determination of mycotoxins. 

This method validation study indicates that the choice of validation parameters is crucial. Checking the method performance in accordance to the obtained validation results should not be omitted. The preliminary imprecision results do not necessarily predict the analytical variation as the method is taken into routine use. The suitability of system controls have to be considered carefully when patient results are accepted according to the general internal quality control principles. Further, surprisingly high variations should be clarified with the manufacturer. The use of past PT samples is highly recommended to predict the future inaccuracy, whenever... 

Caution must be exercised to minimise errors at every stage of the characterisation. Therefore, quahty assurance/quality control principles must be apphed to sampling, sample storage, sample reconcentration and sample analysis. 

Quality assurance and quality control principles in pesticide residue analysis ... 

This chapter introduces the most important aspect of TEQA for the reader After the basics of what constitutes good laboratory practice are discussed, the concept of instrumental calibration is introduced and the mathematics used to establish such calibrations are developed. The uncertainty present in the interpolation of the calibration is then introduced. A comparison is made between the more conventional approach to determining instrument detection limits and the more contemporary approaches that have recently been discussed in the literature (1-6). These more contemporary approaches use least squares regression and incorporate relevant elements from statistics (7). Quality assurance/quality control principles are then introduced. The chapter ends with a comparison of the performance from two hypothetical labs. Every employer wants to hire an analyst who knows of and practices good laboratory behavior. 

Fiegenbaum AV, Quality Control Principles, Practices and Administration, McGraw-Hill, 1951. Ishikawa K, Guide to Quality Control, Asian Productivity Organisation, Tokyo, 1976. 

In addition, throughout the entire manufacturing process, each step must be carried out in accordance with total quality-control principles defined by ISO 9000-9004 or Malcolm Baldridge paradigms readers unfamiliar with these concepts need to consult these documents. 

A solvent free, fast and environmentally friendly near infrared-based methodology was developed for the determination and quality control of 11 pesticides in commercially available formulations. This methodology was based on the direct measurement of the diffuse reflectance spectra of solid samples inside glass vials and a multivariate calibration model to determine the active principle concentration in agrochemicals. The proposed PLS model was made using 11 known commercial and 22 doped samples (11 under and 11 over dosed) for calibration and 22 different formulations as the validation set. For Buprofezin, Chlorsulfuron, Cyromazine, Daminozide, Diuron and Iprodione determination, the information in the spectral range between 1618 and 2630 nm of the reflectance spectra was employed. On the other hand, for Bensulfuron, Fenoxycarb, Metalaxyl, Procymidone and Tricyclazole determination, the first order derivative spectra in the range between 1618 and 2630 nm was used. In both cases, a linear remove correction was applied. Mean accuracy errors between 0.5 and 3.1% were obtained for the validation set. 

Storage and receiving are activities that can greatly contribute to a safe and economic operation. It is here that quality control can be achieved at minimal cost. Label verification and other quality assurance measures can increase the confidence level that the correct chemicals have arrived, thereby potentially circumventing the use of wrong chemicals. Wrongly shipped chemicals can be returned to the manufacturer with minimal or no cost to the batch operation owner. As with all processes and activities it is of great importance to apply the principles of inherent safety, in particular the minimization and attenuation principles (CCPS G- 41). 

Although I have defined terms such as quality control and quality assurance in this chapter, what is important is not the definition but the deeds which it imbues. Whether we call the set of principles I have listed under the heading Quality assurance, Quality Assurance, Quality Improvement or Quality Control makes no difference since it does not change the set of principles. We often seem to invent a term then decide what it means rather than invent or discover a set of principles and think of a suitable name which conveys exactly what we intend without confusing people. Instead of saying Quality control is. .. or TQM is. .. to which there will be many propositions, we should be asking What should we call this group of principles so that we can communicate with each other more efficiently As Shakespeare once said That which we call a rose/By any other name would smell as sweet. ... 

Quality Management system priorities to consider are management responsibility, quality system principles, auditing, contract review, design control, corrective action, document control, quality records, training, product safety and liability, and statistical techniques, because these are critical aspects of the Quality Management system where Xmple Inc. already has some systems in place. 

In the final analysis, market price and sales volume are functions of the quality standards offered and the buyer s degree of confidence that the product will conform to the standards. Maintenance of buyer s confidence requires inspection to screen out all nonconforming products, or control over variability of quality during production and distribution to a degree where few, if any, products fail to meet the standards. Screening inspection of the finished product cannot improve quality it merely serves to segregate unacceptable from acceptable product, and results in loss of production capacity and costly waste and salvage. The second consideration provides the only sound basis for quality control in frozen food production and distribution. It operates on the old principle that an ounce of prevention is worth a pound of cure. ... 

Much valuable research has been devoted to developing the basic principles for the production of frozen fruits and vegetables of high and uniform quality. If this knowledge could be applied to its fullest extent, there would be little need for concern over the quality of such foods. Before this can be done, those responsible for quality control must be provided with suitable standards of quality and condition, and objective methods of analysis which will clearly indicate conformance or nonconformance to the standards. Responsibility for this resides with the research food technologist or chemist. It constitutes a rich field for profitable and practical research. 

The context of this work, at least superficially, is quality control in the chemical and pharmaceutical industries. The general principles apply to any form of (chemical) analysis, however, whether in an industrial setting or not. Other readers need only to replace some phrases, such as Health Authority with discriminating customer or official requirements with market expectations, to bridge the gap. The specifically chemical or pharmaceutical nomenclature is either explained or then sufficiently circumscribed so that the essentials can be understood by students of other disciplines. 

There is the potential to develop a protective vaccine/immunization programme for each and every infectious disease. Whether or not such vaccines are developed and deployed is related to the severity and economic impact of the disease upon the eommunity as well as the effects upon the individual. Principles of immunity and of the produetion and quality control of immunological products are discussed in Chapters 14 and 15, respeetively. 

Permeability is another method for obtaining information about pcirticle diameters. If one packs a tube with a weight of powder exactly equal to its density, and applies a calibrated gas pressure through the tube, the pressure drop can be equated to an average particle size. The instrument based on this principle is called the "Fisher Sub-Sieve Sizer ". Only one value can be obtained but the method is fast and reproducible. The instrument itself is not expensive and the method can be applied to quality control problems of powders. Permeametry is usefiil in the particle range of 0.5 to 50 n. 

Quality control is intended to monitor and evaluate the performances of both food and human processes that contribute to food quality. The basic principle of this function is the control circle that involves (1) the taking of a process sample by the analysis or measuring unit, (2) determining whether process results meet set tolerances or limits, (3) judging the character and level of any discrepancy, and (4) application of corrective action to adjust the system to an acceptable level (Figure 7.1.1). A distinction is made between measuring and analysis, whereby the first involves direct measurements (e.g., pH, temperature) and the second involves taking samples, sample preparation, and actual analysis. ... 

While quality was formerly achieved by inspection of final products, it is accomplished now by prevention through controlling critical steps in the production processes along the agri-food chain. Hazard analysis critical control points (HACCP) represent a typical example of such a preventive approach. Although this concept was developed primarily to assure food safety, the basic principle is also applicable to assuring non-safety quality attributes such as color, flavor, and nutritional value. " This section translates the HACCP principles into a critical quality control point (CQP) concept that can be part of a system to assure food quality. 

This part concerns the actual quality control system by which the critical product and process parameters that impact final quality attributes are monitored and corrected in the production process. CQP monitoring systems can be based on the principle of a control circle as explained in Section 7.1.3. The following principles must be followed ... 

Ingamells CO, PiTARD FF (1986) Applied Geochemical Analysis, pp L-84.Wiley, New York. International Federation of Clinical Chemistry (IFCC) (1978) Expert Panel on Nomenclature and Principles of Quality Control in Clinical Chemistry. Clin Chim Acta 83 L89F-202F. International Organization for Standardization (ISO) (1993) Guide to the expression of uncertainty. Geneva. 

The purpose of this monograph, the first to be dedicated exclusively to the analytics of additives in polymers, is to evaluate critically the extensive problemsolving experience in the polymer industry. Although this book is not intended to be a treatise on modem analytical tools in general or on polymer analysis en large, an outline of the principles and characteristics of relevant instrumental techniques (without hands-on details) was deemed necessary to clarify the current state-of-the-art of the analysis of additives in polymers and to accustom the reader to the unavoidable professional nomenclature. The book, which provides an in-depth overview of additive analysis by focusing on a wide array of applications in R D, production, quality control and technical service, reflects the recent explosive development of the field. Rather than being a compendium, cookery book or laboratory manual for qualitative and/or quantitative analysis of specific additives in a variety of commercial polymers, with no limits to impractical academic exoticism (analysis for its own sake), the book focuses on the fundamental characteristics of the arsenal of techniques utilised industrially in direct relation... 

The principles of quality assurance are commonly related to product and process control in manufacturing. Today the field of application greatly expanded to include environmental protection and quality control within analytical chemistry itself, i.e., the quality assurance of analytical measurements. In any field, features of quality cannot be reproduced with any absolute degree of precision but only within certain limits of tolerance. These depend on the uncertainties of both the process under control and the test procedure and additionally from the expense of testing and controlling that may be economically justifiable. 

Continuous quality control is based on principles that firstly were used in the system of quality control charts (QCC, Shewhart [1931]). Today, admittedly the monitoring of the characteristics of a process or product in order to detect deviations from the target value is not tied to charts but is mostly done by computer, although it is frequently still called a control chart system. 

From the consumer s perspective, cost is an important characteristic of the food and the best buy is the product that is considered to have the best ratio of quality and price. So consumers should welcome any measure that will improve quality at no extra cost or reduce the cost at no reduction in quality. In principle, using a CCP-based system at the level of a supply chain is supposed to do just that, since it will ensure that the controls are taking place at the steps where they can be implemented most effectively, thus eliminating superfluous double or triple testing of the same thing, or unnecessary waste when food is discarded because its safety is uncertain. 

These principles are supported by a related set of studies that showed reliable inter-laboratory IHC staining for Her2/neu, ER, and so on could be achieved based on optimal AR-IHC protocols and stringent quality control using standard reference materials, even though ischemia time itself was uncontrolled and unknown.38 0... 

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