## 2 Literature Review
### Quality and Visual Cues for Foods  
The quality of a product may have an impact on the food choice process, but only if it is perceived [38]. The visualization of quality cues is necessary for understanding and used at the time of choosing a food product since the first sensory contact of the consumer with food is through the eyes [39]. Thus, before food is effectively chosen by the consumer, visual attention is directed to visual cues, which provide information about the characteristics of food through words, images, symbols, or the appearance of the product [39; 40]. Consumers make purchasing decisions based on intrinsic and extrinsic visual cues that they correlate to specific attributes based on prior experience and credibility [41]. Intrinsic visual cues are inherent to the food itself and cannot be manipulated without affecting its physical properties--these include appearance, taste, and texture. Extrinsic visual cuesare related to the product and include labelling, packaging, marketing information or situational contexts [42]. Regarding beef, the main intrinsic visual cues reported are cut, color, fat content, flavor, tenderness, and taste [41; 42; 43; 44; 45; 46; 47; 48]. Extrinsic visual cues represent all the other product characteristics, such as brand, price, packaging, origin, and information regarding animal production [5; 43; 49]. Exposure to visual cues can promote variations in consumption, acceptance, visual attention, and the creation of expectations by the consumer [39], which can have a halo effect, modifying the perception of flavor and acceptability of food. In this sense, visual properties are critical for holding visual attention and swaying the choosing of products sold by their own appearance, and not by the packaging design. According to previous studies, foods marketed by their own appearance stand out by visual cues of color, texture, and the perception of flavor stimulated by color [40]. Regarding beef, studies have shown that the acceptance of beef with information highlighting a dark red color is higher compared to those with a bright red color (cherry red) [50; 51]. Additionally, it was found that intrinsic and extrinsic visual cues significantly influence consumer emotions, hedonic perception, and even food purchase intention, and the provision of additional information, such as names or information on the packaging, can increase the choice and probability of purchase [52]. From a Brazilian perspective, the main visual cues of beef presented to consumers at points of sale can be divided into two groups: (a) regulated: mandatory labelling information by governmental agencies, such as beef cut name, manufacturer name, expiration date, etc. ; and (b) strategic: explored in the form of claims or seals by private initiatives. When buying fresh beef in Brazil, consumers can purchase from one of three situations: meat available in butcher shops and packed according to the consumer's request, chilled meat cuts, and vacuum-packed meat [53]. When purchasing from a butchery or as chilled meat, the consumer has little extrinsic information available about the product--there is a focus mainly on price and visual cues such as appearance. On the other hand, vacuum-packed meats are labelled with regulated visual cues for packaged products, namely: weight, origin, federal inspection seal, product preservation, brand, batch identification, manufacture date, expiration date, and registration number [54]; and strategic visual cues, such as breed, premium quality seals, livestock system, and age, among others. When purchasing cooked beef (in a restaurant), two main options are available: a la carte dishes prepared with specific beef cuts or all-you-can-eat buffets with various types of meats and beef cuts [55]. In both cases, consumers are provided with specific information on price, regulated visual cues, and strategic visual cues, such as animal breed. Usually, additional information can be obtained from the waiter or even from the appearance and aroma of the meat.