(Source: Food Research International, 2017 99(1):58-71)

        During the last century, industrialized countries have overcome lack of food security with the key contribution of agrifood industrialization. Food processing has played a crucial role as it allowed extending the shelf life of food products, reduced food losses and waste, as well as improved nutrient availability and optimization. However, day-to-day consumer perception focuses on other aspects than these achievements. In modern societies, the increasingly globalized markets and greater processing in the food chain has contributed to a perceived distance and knowledge gap between people and food manufacturers (e.g. how food is produced, where is it produced, etc.). 

       For instance, food contamination accidents have affected Europe in the last decades, such as BSE and dioxin. Consu umers are concerned about the heavy use of pesticides in the conventional and intensive agricultural practices, the use of artificial ingredients, additives or colourants such as E133, and the adoption of controversial food technologies like GMOs. This has prompted consumers to become skeptical or worried about adverse health effects entailed in this food system. Moreover, the growing public concemn about the contribution of the food system to climate change and its overall negative effects on sustainability have led const environmental and social consequences of food production. 

     The trends of healthiness and sustainability have triggered consumers into considering which components are used in the food products that they cat in everyday life. A new trend in food products has emerged, which is often summarized under the umbrella of the so-called "clean labe!" and has been taken up by a multitude of food industry stakeholders. The term clean label itsclf appeared for the first time during the 1980s when consumers started to avoid the E-numbers listed on food labels becausc they were allegedly associated with negative health effects. The food industry has started to respond to the increasing consumer demand of such clean label products by supplying food products that are perceived as 'cleaner'. For example, in 2010 Heinz tomato ketchup was reformulated to remove high fructose com syrup from the ingredient list and was renamed as Simply Heinz. 

        To date there is no an established, objective and common definition of what a clean label is, but rather several definitions or interpretations, often provided by market trend reports but not backed up by consu umer behavior re earch or theory. Ingredion (2014) recommends to consu mers that "a 'clcan label' positioned on the pack means the can be positioned as 'natural', 'organic' andor free from additives/preservatives'" Edwards (2013) defines a clean label "by being produced free of chemicals' additives, having easy-to-understand ingredicnt lists, and being produced by use of traditional techniques with limited processing"' One of the key questions is which ingredients may be part of a clean label, or, more importantly, which ingredicnts define a clean label product by their absence. Busken (2013) proposes that the answer to this depends on the consumer perception of an ingredient. 

       With regard to the clean label trend, we argue that hints about the item being a clean label food are used as such cues. We argue that their casy usage and inference to desirable, but unobservable characteristics explains the popularity of clean label. Typically, consu umers might use cues found on the front of the package (FOP) such as visuals indicating naturalness, organic certification logos, or free-from claims of producers, thus, these products might be perceived as clean labcl. However, we argue that not only peripheral processing is expected to play a role for clean label, but also central processing. In some cases consumers might proceed to access information on the back of the pack (BOP) in store or, even more likely, at home. There is a greater likelihood that consumers who are engaging in this effort are characterized by greater involvement and thus motivation to process, or that the situation at home provides better opportunity to look at infornation and engage with it, thus, identifying the product as clean labei. Therefore, central, more in-depth and conscious information processing will occur more likely at home. Consumers might then look at the ingredient information or nutrition facts more closely, and inspect and assess whether or not they think the product is a clean label food in their opinion. However, given that consumers might not find this easy to assess, they might nevertheless rely on heuristics, such as the degree to which ingredient names sound chemical or are unknown, or the mere length of the ingredient list. In addition to using this observable feature as a cue to a product desired quality, consumers might also favor products with understandable, short, known and simple ingredient lists in order to reduce the cognitive effort needed in assessing the product. 

       We suggest to define clean label, both in a broad sense, where consumers evaluate the cleanliness of product by assumption and through inference looking at the front-of. pack label and in a strict sense, where consumers evaluate the cleanliness of product by inspection and through inference looking at the back-of-pack label. Results show that while 'health' is a major consumer motive, a broad diversity of drivers influence the clean label trend with particular relevance of intrinsic or extrinsic product characteristics and socio-cultural factors. However, 'free from' artificial additives/ingredients food products tend to differ from organic and natural products. Food manufacturers should take the diversity of these drivers into account in developing new products and communication about the latter. For policy makers, it is important to work towards a more homogenous understanding and application of the term of clean label and identify a uniform definition or regulation for 'free from' artificial additives/ingredients food products, as well as work towards decreasing consumer misconceptions.