Table 2 Measurement tools that evaluates “how healthy/unhealthy” are the food and beverages sold within the informal food outlets

Costa, et al., 2019 [33]

Belo Horizonte, Minas Gerais state, Brazil

Open-air food markets (e.g., fixed and mobile establishments).

Healthy food store index (HFSI): measures availability, variety, advertising of healthy items versus ultra-processed items.

This index was based on an audit tool from ESAO study [34].

Healthy (fruits and vegetables) and unhealthy (sweetened beverages, corn chips, and cream-filled cookies).

HFSI: classified outlets as healthy (positive score) or unhealthy (negative score). The score ranges from 1 to 16 [33]

Audit tool: inter-rater reliability ranges from 0.66 to 0.95. Test-retest ranges from 0.61 to 1 [35].

Duran et al., 2013 [34]

Sao Paulo, Brazil

Convenience stores, public-owned specialized fruit and vegetables (FV) markets, privately-owned specialized FV markets/stores, open-air food markets, corner stores, local grocery stores, large chain grocery stores, large chain supermarkets, delis.

Healthy food store index (HFSI): measures availability, variety and signage/promotion of the 10 most commonly purchased fruits and vegetables, and availability and signage/advertising of selected snacks items (sugar-sweetened beverages, chocolate sandwich cookies and processed corn chips) in the metropolitan area of Sao Paulo city.

This index was derived from tools that assess healthy and unhealthy food availability, quality, variety, price, and signage/advertising or promotion.

Healthy (fruits and vegetables) and unhealthy (sweetened beverages, corn chips, and cream-filled cookies).

HFSI: classified outlets as healthy (positive score) or unhealthy (negative score).

The score ranges from 1 to 15 [34]

Tools: pilot tested. Inter-rater and test-retest reliability ranged from 0.50–0.95 [35].

Duran, et al., 2015 [35]

Sao Paulo, Brazil

Open-air-food markets (feiras-livres) (e.g., mobile or semi-fixed food markets)

Availability, variety, quality, pricing, signage and promotion of 10 most frequently purchased fruit and vegetables and the three most frequently consumed ultra-processed foods in Sao Paulo Metropolitan Region.

Healthy (fruit and salads: orange, banana, papaya, apple, tomato, onions, carrot, lettuce) or unhealthy (sugar-sweetened beverages: soda, sugar-free soda, sugar-sweetened nectar/juice, fruit-flavored drink mix, chocolate sandwich cookies and corn chips).

Availability and quality are reported as percentage. Variety and price as a mean.

ESAO-S: test-retest reliability ranged from 0.61 to 1. Inter-rater reliability ranged from 0.66 to 0.95. For construct validity, these tools were able to discriminate between store types and different neighborhoods [35].

Leite, et al., 2012 [36]

Sao Paulo, Brazil

Fixed or mobile outlets.

Characteristics of stores, physical structure, inventory of food sold, which assessed the availability of food according to processing.

3 groups: unprocessed or minimally processed food (e.g., fresh meats and milk, grains, legumes, oilseeds, fruit and vegetables, roots and tubers, tea, coffee, herbal infusions and bottled water), processed ingredients (e.g., oils, fats, flour, pasta, starches and sugars, corn syrup, lactose and soy and milk protein), ultra-processed food products (e.g., bread, cereal bars, biscuits, chips, cakes, candies, ice cream and soda, frozen pasta and pizzas, sausages, breaded chicken, fish strips, canned or dehydrated soups, infant formulas and baby soups) [37].

Not available

Gelormini, et al., 2015 [38]

Maputo, Mozambique

Establishments selling ready-to-eat food or beverages for any venue on the streets, including carts, trucks, stands or any improvised informal setups.

Business’ operating hours and location, type of food products available, size of portions, price, and types of food packages. In addition to nutritional composition.

Monteiro, et al., 2016 [39]

Brazil

Formal and informal environment.

According to food processing.

4 groups: unprocessed or minimally processed foods (e.g., fresh, squeezed, chilled, frozen, or dried fruits and leafy and root vegetables: grains such as brown, parboiled or white rice, corn cob or kernel, wheat berry or grain; legumes such as beans of all types, lentils, chickpeas; starchy roots and tubers such as potatoes and cassava, in bulk or package; fungi such as fresh or dried mushrooms; meat, poultry, fish and seafood, whole or in the form of steaks, fillets and other cuts, or chilled or frozen; eggs; milk, pasteurized or powdered; fresh or pasteurized fruit or vegetables juice without added sugar, sweeteners or flavors; grifts, flakes or flour made from corn, wheat, oats, or cassava; pasta, couscous and polenta made with flours, flakes or grits and water; tree and ground nuts and other oil seeds without added salt or sugar; spices such as pepper, cloves and cinnamon; and herbs such as thyme and mint, fresh or dried; plain yoghurt with no added sugar or artificial sweeteners added; tea, coffee, drinking water), processed culinary ingredients (e.g., salt mined or seawater; sugar and molasses obtained from cane or beet; honey extracted from combs and syrup from maple trees; vegetable oils crushed from olives or seeds; butter and lard obtained from milk and pork; and starches extracted from corn and other plants), processed foods (e.g., canned or bottled vegetables, fruit and legumes; salted or sugared nuts and seeds; salted cured or smoked meats; canned fish; fruit in syrup; cheeses and unpacked freshly made breads), ultra-processed food and drink products (e.g., casein, lactose, whey, and gluten, and some derived from further processing of food constituents, such as hydrogenated or interesterified oils, hydrolyzed proteins, soy protein isolate, maltodextrin, invert sugar and high fructose corn syrup, dyes and other colors, color stabilizers, flavors, flavor enhancers, non-sugar sweeteners, and processing aids such as carbonating, forming, bulking and anti-bulking, de-foaming, anti-caking and glazing agents, emulsifiers, sequestrants and humectants).

AUDITNOVA: Content validity index was 0.91 and inter-rater and test-retest reliability was > 0.80 [40].

Sousa, et al., 2019 [41] and Albuquerque, et al., 2019 [42]

Maputo, Mozambique

Dushanbe, Tajikistan

Establishments selling ready-to-eat food or beverages for any venue on the streets, including carts, trucks, stands or any improvised informal setups.

Includes business characteristics, type of physical setup and mobility, gender of the vendor, operating hours, location, food availability, size of portions, prices and type of food packages.

Prevalence of three groups: 1) fruits (fleshy or dry), 2) beverages (e.g., soft drinks, water, fruit juices, milk, yogurt, alcoholic beverages, energetic drinks, homemade fermented beverages, tea and alcoholic drinks) and 3) food other than fruit and beverages. This group was classified as homemade or industrial (homemade – foods cooked and/or prepared at home, industrial – food industry products)

Not available

Bridle, et al., 2015 [43]

Mazatlán, Sinaloa, Mexico

Food outlets (restaurant, tortilleria, hot food cart, abarrotes)

Observational tools derived from a synthesis of literature review, consultation with local nutrition and policy practitioners, and NEM-S, NEMS-R, were used to evaluate food and beverages quantity, prices and promotions of informal or formal outlets around secondary schools. In outlets that offer ready to eat food or inside consumption, availability and prices of healthier options were collected through the menu.

Two groups of special interest were observed: 1) healthy (fruit and vegetables) and 2) unhealthy (beverages and packed snacks).

Classifies outlets as more-healthier and less-healthier

based on proportions. More healthier options were outlets with the widest variety and quantity of fresh fruit and vegetables. Less-healthier food outlet with a preponderance of packaged snacks and SSBs.

Not available

Lucan, et al., 2015 [44]

New York city, USA

Farmer’s markets

Evaluates all food items offered in farmer’s markets and fresh-produced items offered in nearby stores. In addition, this form inquiries about food quality (freshness and purity/naturalness), variety and price.

Produce items (fruit: fresh and dried varieties of generally-sweet, seed-bearing, whole produce, and vegetables: more-savory, seed-bearing, whole produce, shoots, leaves, flower buds, tubers, roots, bulbs, mushrooms, herbs) and two of non-produce items (other whole foods such as nuts, seeds, eggs, cheeses, and whole-grain products) and refined or processed foods (non-whole-grain baked sweets, savory items, juices/ciders, sugar-added items, concentrated sweets.

Total food items sold at farmer’s markets were reported as proportions.

Pilot testing showed complete agreement between researchers for audit form items. Test-retest and validity were not reported [44].

Hosler, et al., 2011 [45]

New York city, USA

Permanent or mobile urban food stores and farmer’s market.

Contains two sections, the front section records availability, placement, prices of food and non-food items and stores’ physical characteristics. The back section contains information related to outside advertising and health promotion messages.

Availability of healthier alternatives, characterized by varieties that were low- or nonfat, higher-fiber, no-sugar added, or packed in plain water such as fruits: fresh, canned or frozen, vegetables: fresh dark green/orange, canned or frozen, grain and grain products: higher fiber bread (≥2 g/slice), brown rice, higher fiber pasta (≥5 g/2 oz), cereal (oatmeal), beans: dried or canned in water, plain water, milk (1% or skim), fish (tuna can in water, fresh fish filet, frozen fish filet), fresh eggs.

Food items were reported as available (yes/no).

Inter-rater reliability for inside the store ranges from 0.59 to 1. Test-retest and inter-rater reliability for outside store ranges from 0.94 to 0.99 [45].

High degree of inter-rater and test-retest reliability implies construct validity [45].

Lucan, et al., 2013 [46]

New York city, USA

Vending vehicle (e.g. cart, stand or truck).

Direct observation regarding general characteristics, location, functionality of vending vehicles, type of vehicles, and location, types of food and beverages and interesting observations.

Types of vending: healthier (whole food like a fruit, vegetables, unprocessed grains, unsweetened nuts), less-healthier (processed and prepared food) and mixed (offering both). Vending items were classified as fresh produce, ethnic foods, other prepared foods, frozen novelty and others. Results were reported as numbers and percentages [47].

Pilot testing was conducted with essentially perfect agreement.

Martins, et al., 2013 [48]

Sao Paulo, Brazil

Supermarkets, grocery stores, convenience stores, farmer’s markets, produce markets, bakeries, butcheries, candy stores and street food stands.

NEMS-S: 5-minutes interview with the manager to collect: work days, time of opening and closure, the main products sold. Observation characteristics: physical space (fixed or mobile) and an inventory of the foods sold and a record of the availability of 33 food groups listed in the instrument, prices of foods and the quality of fruit and vegetables.

According to food processing and the Harvard Healthy Eating Pyramid recommendations:

Healthy (fruit, non-starchy vegetables, roots and tubers except for potatoes and carrots, chicken, eggs, unprocessed seafood, milk, some cheeses, yogurts, brown rice, whole grains, beans, nuts), intermediate (oils, white rice, wheat flour, plain pasta, whole-grain bread) and unhealthy (mostly ultra-processed food)

Healthy eating promotion score was used to classify food establishments according to food availability, price and quality.

Pilot-testing, internal consistency (0.71 for group 1, 0.068 for group 2, 0.93 for group 3), inter-rater reliability (0.61–0.80) and validity of mean score (p < 0.001).

Byker, et al., 2015 [49]

USA

Farmer’s markets

The tool has 27 unique items. Measures the availability and quality of food items and key characteristics about the operations of the market.

Healthy (fruit, vegetables, meats (pork: loin pastured, ground beef: lean ground beef with less than or equal to 10% fat, chicken: skinless chicken breast or whole chickens, fish: shellfish, whole fish, fish that has been sliced, eggs: regular and free range, cheeses: goats, cow’s milk, feta or lower calorie versions, and bread and grains: wheat, rye, other darker breads, samples: fruit and vegetables, salsa with chips).

Food items were reported as available (yes/no).

Pilot testing inter-rater reliability (50–100% agreement), face validity.

Lucan, et al., 2020 [50]

New York city, USA

Storefront (e.g., convenience, supermarkets, groceries) and non-storefront (street food, mobile food outlet)

Identifies the name, type, street address and the hour of service of storefront and non-storefront food and beverages outlets.

Healthy (fruits, vegetables, nuts, whole grains, water and unflavored milk), less-healthy (refined sweets, salty/fatty fare, sugar sweetened beverages and alcohol), neither healthy or unhealthy (100% juice and diet drinks, eggs, cheese and poultry).

Results were reported as percentage.

Inter-rater reliability was high.

Green, et al., 2020 [51]

Ghana and Kenya, Africa

Formal and informal outlets (e.g., kiosks, local vendors, vegetable/fruit stands/table tops).

Classifies food outlets as informal or formal. Informal outlets are those not movable, not permanent and/or those that have small-scale operation. In addition, items being sold and advertising are measured.

Healthy (e.g., raw/uncooked beef, pork, chicken fish/shellfish, milk, eggs, grains, cereals, roots, tubers, beans, peas, lentils, cashews, sesame seeds, jollof rice, banku, waakye, mango, watermelon, oranges, peppers, onions) or unhealthy (cooking oils or fats, jam, hazelnut spread, cola, soda, beer, vodka, wine, fried plantain, processed meats, pies, cake, ice cream, chocolate, pizza, lasagna, ketchup, shito) based on a nutrient profiling classification.

Results are reported as a percentage of all records.

Pilot testing was performed in smaller areas.

Valdez, et al., 2012 [52]

South border Texas, USA

Mobile and home-based food vendors.

Includes demographics of vendors, characteristics of the business and work (length of time in business, initial investment, marketing area, percentage of household income from vending, hours of vending, food products sold by season, advertising, source of food products, scheduling strategy and target customers), working conditions and perceived relationships with customers.

Healthier (fruit and vegetables, juice with no added sugar or bottled water) and less-healthy (salty/fried, sweet or frozen snacks, sugar-sweetened beverages). Results are reported as percentage.

Not available