Feeding the ever-increasing population while providing food security has become a critical issue. This issue creates a need for coordinated international action to prevent food adulteration on a global scale. Food adulteration is associated with unfair competition and serious losses in the food sector and its organizations, leading to a loss of consumer confidence. This chapter is devoted to the characteristics of three general topics as the study object, including counterfeit foods and key aspects regarding analytics and chemometrics. The issues discussed pertain to verifying the authenticity/adulteration of all the food groups, such as meat, fish, other seafood, milk and dairy products, honey, cereals and grains, olive oils and seed oils, vegetables and spices, mushrooms, fruits (including fruit juices), tea, coffee, cocoa, sugar and its products, mineral and drinking water and wines and other alcoholic beverages. Since the elemental and stable isotope profiles of these food groups have been quantified using state-of-the-art analytical techniques/methods, the general principles of analytical applications have been discussed. As the original analytical data require computational processing, the characteristics of chemometrics and its application have been investigated. The wide range of applications of chemometrics in the assessment of food quality has been revealed. This development enables combining state-of-the-art analytical methods/techniques with modern chemometrics. Therefore, it has been possible to recognize the authenticity/adulteration of the food chain. Because of the complex composition of the food matrix, the study of a food’s chemical profile should be related to the use of multivariate analysis. Therefore, a multivariate assessment of food authenticity is acceptable and recommended.