The present innovative, 10-month trial supports the potential of urban corner stores as a feasible and sustainable venue for improving the community food environment.
Programme impact on increasing healthy foods availability and sales was modest, but positive. In intervention stores, the stocking of some promoted healthy foods improved and was well sustained even six months after the programme was completed. Although the present study focused on increasing the stocking of healthy foods at corner stores, increasing the allocation of shelf space to healthy foods is another approach that should be tried in future studies, since this has been associated with increased consumption of such foods among community residents(23
). Furthermore, we feel that corner store-based interventions need to first focus on assessing the feasibility of healthy foods stocking and sales before different varieties of healthy foods can be addressed, since stocking and selling healthy foods itself is the major issue. Increasing the availability of different types of healthy foods in each food category is the next step to consider.
In our study, when sales patterns were compared with stocking, weekly sales of promoted foods increased in intervention stores, corresponding to the stocking of those foods. When the stocking of some promoted foods such as high-fibre cereals and low-fat milk did not improve, there was also no improvement in sales of those foods.
Promoted healthy foods vary in their acceptability to corner storeowners (in terms of stocking) and to customers (in terms of purchasing). Some foods were more acceptable to both corner storeowners and customers than others within the same category. For example, the message of the first intervention phase was ‘healthy breakfast’ and the promoted foods were low-sugar and/or high-fibre cereals. Although the storeowners were recommended to stock both low-sugar and high-fibre cereals, the storeowners increased only the stocking of low-sugar cereals. The rationale by storeowners was that they increased the stocking of low-sugar cereals because customers preferred it over high-fibre cereals(21
). These preferred foods can be used as ‘initial foods’ at the beginning of the intervention to encourage storeowners to stock healthier foods. Increasing the availability of the initial foods is critical for success of corner store-based interventions because these initial foods are more acceptable to customers and acceptance of those foods by the community will lead to better sales which motivate corner storeowners to try and stock other healthy foods. Furthermore, even small increases in the sales and stocking of healthy foods at corners stores suggest great potential of corner store-based programmes since, unlike supermarkets, corner stores and the neighbouring community can quickly respond to small changes of each other. If corner storeowners stock a few items and sell them regularly, they are likely to continue stocking those items because they are very responsive to communities’ demand.
Previous store-based interventions have shown that customers’ purchasing behaviours are more likely to improve for programmes lasting longer (more than 2 years)(24
). Since the current study lasted only 10 months, it is possible that a longer trial would result in more statistically significant programme impacts on promoted food sales and storeowners’ psychosocial variables.
Overall, the impacts of the BHS programme on storeowner psychosocial factors were small. Decreases in self-efficacy for stocking some of the promoted foods appeared to be related to seasonality or storeowners’ perceived barriers to stocking these foods. For example, storeowners consistently referred to high-fibre cereals as one of the least popular foods due to low customer demand. These findings are consistent with those of Skerratt(27
), who found that unpredictable purchasing patterns of the community reduced food providers’ confidence in supplying particular foods, resulting in decreased self-efficacy for stocking those foods. In addition, corner storeowners often met challenges in acquiring promoted foods. Although the storeowners could order new foods from vendors, most did not want to change their routine ordering procedures due to language barriers, concerns about low customer demand, or the financial burden of purchasing goods in bulk. In spite of monetary incentives given to intervention stores to cover financial risk, the storeowners were still reluctant to purchase new foods and felt bad about unsold items. Future corner store-based nutrition interventions in urban communities should take into account various aspects such as corner storeowners’ perceived barriers and structural problems related to food stocking and ordering procedure.
In the present study, supermarkets were included only for the analysis of psychosocial variables. Stocking healthy foods was not a major issue at supermarkets compared with corner stores since supermarkets already stocked a wide variety of healthy foods. Also, the promoted food sales were reported only for corner stores because participating supermarkets later proved reluctant to release their sales data.
The study had several limitations. Due to lack of a computerized sales tracking system at corner stores, promoted food sales were determined from storeowners’ recalls using weekly food sales records. Total store sales or comparative food sales were not collected because these caused too much subject burden on the storeowners. While the possibility of secular changes is of concern, our use of a set of comparison stores where stocking and sales did not increase ameliorates this concern. An increase in stocking or promoted foods sales only in intervention area stores is very unlikely considering the comparable characteristics of the two study areas.
Also, the costs of the foods were not assessed in our study. However, when we selected the promoted healthy foods for the programme, we made sure the foods were comparable in cost to the same type of less healthy foods.
Another possibility regarding the increased promoted food sales in intervention stores is that intervention corner storeowners may have sold the promoted healthy foods at a loss. However, the storeowners said that they rarely sell items at a loss because it results in a lot of complaints from customers when the sale is over. Another main challenge was the high turnover of store managers and corner storeowners. After collecting baseline data, some corner stores closed or changed ownership, forcing us to recollect baseline data or recruit additional stores.
In spite of these limitations, the findings of the present study provide important implications for future corner store-based nutrition interventions in urban communities. We were able to increase stocking and sales of some healthy foods in urban corner stores, and these changes were sustained six months post-intervention. Corner store and other small store interventions may be a viable means of improving access to healthy foods in poor urban settings.