Rapid, non-targeted, validated mass spectrometric methods in food authentication: What exactly is our target?

Recommendations to facilitate the adoption of non-targeted mass spectrometry-based methods in food authenticity assessments.      Introduction Food authenticity is one of the major concerns of producers, consumers, and regulators. Today it is important to verify that food package labelling corresponds to the actual characteristics of the food. For example, geographic origin and production procedures must be verified in order to protect consumers from fraud and to comply with national and international legislation. The globalisation of the food trade and the complexity of supply chains makes food more prone to adulteration and both intentional and unintentional fraud is perpetrated. Food fraud often involves economically motivated adulteration (EMA), where the use of low-cost adulterants increases profit margins (Everstine, 2017). The risk of food adulteration dramatically increases proportionately with the complexity of the supply chain. Spices, for example, are expensive items that are often adulterated with cheaper bulk materials (Wilde et al. 2019; Black et al. 2016; Lefeuille et al. 2020). Therefore, robust authenticity procedures capable of verifying food origin (geographic or genetic) and production method (organic, conventional, traditional procedures) as well as intentional and accidental adulteration are necessary. (Cubero-Leon et al. 2014).  Due to the variety of food adulterants, production procedures, and geographic origins, testing for food authenticity with targeted methods has become increasingly difficult. In order to overcome this issue, in the last decade we have been overwhelmed by a growing number of non-targeted methods for food authentication (Danezis et al. 2016). In 2015, the Committee on the Environment, Public Health and Food Safety of the European Parliament released a report (2013) on food chain and food control fraud that called on the member states to research the development and implementation of fingerprinting and sensory methods to facilitate and accelerate the verification of the authenticity of food commodities (EU Report 2013/2091-INI). In the same context, the EU also invested in the TRACE project aimed at developing generic and commodity-specific traceability systems to enable the objective verification of food origins. The field of non-targeted approaches in food authenticity has experienced massive horizontal growth throughout the recent decade with no single method breaking through the regulatory barrier for approved use.  A wide range of food matrices have been analysed by mass spectrometry-based non-targeted approaches, including flours (Miano et al. 2018), milk (Riuzzi et al. 2020), spices (Black et al. 2016; Wilde et al. 2019), beers (Biancolillo et al. 2014), olive oil (Cavanna et al. 2020), juices (Gómez-Ramos et al. 2020), and fish (Porcari et al. 2014). The most significant challenges faced by chemists are a lack of unique guidelines and regulations for development and validation of non-targeted methodologies, no clear definition of terms, difficulty in obtaining large amounts of authentic samples to create the reference model dataset, well-defined workflows, and user-friendly chemometric software with all the necessary algorithms. Without a standardized workflow, regulatory agencies lack enforceable guidelines or action on non-targeted methods (Gao et al. 2019). Recently, the United States Pharmacopeia (US