Quality Control: Analysis Methods, Sampling and Sample Pretreatment

The development of new methods that might or might not involve sophisticated techniques for the quality control of food products continues increasing according to consumer requirement of food safety and authenticity issues. The production of fakes is a worldwide problem that includes food products. Some examples can be found on olive oils, honeys and alcoholic beverages such as table wines and spirits (Contreras et al., 2010; Gallardo et al, 2009; Marcos et al., 2002; Zhang et al., 2001; Zhu et al., 2010). Therefore, food authentication concerns both authorities and food processors to avoid the unfair competition from counterfeiters who exploited the economic advantage by producing and selling fake food products. Food companies have adopted different strategies to improve the positioning of their brands on the market. These strategies not only include the food quality control based on the identification and reduction of forbidden compounds but also on monitoring the key compounds that enhance the food value. In this chapter a practical review of methods for quality control on compounds and on the confirmation of food authenticity is presented. Non-destructive testing sample methodologies that have found new applications in the field of quality assurance are discussed in terms of their potential use in food industry. Thus, the use of spectroscopic techniques with chemometric analysis for the classification of food samples based on quality attributes is also discussed in this chapter. The optimization of the analytical methods is based on the selection of fundamental working conditions (sampling, pretreatment, selectivity, linearity, range determination, sensitivity, limit of detection, precision and accuracy, etc.) according to which the suitability of a selected method might be evaluated. One of the most important steps in the analytical method for compound determination in biological matrices is the sample pretreatment. The purpose of a pretreatment is to release analytes from compounds and phases as well as to remove components which have adverse impacts on the analytical signal. On the other hand, before any analytic treatment it is necessary to take into account some preliminary procedures that involve statistic analysis (Cochran, 1977; Hinkelmann &