Implementation of a salt substitute intervention using social marketing in resourced-limited communities in Peru: a process evaluation study

Objective

This study aimed to conduct a process evaluation of a salt substitute trial conducted in Peru.

Methods

Through semi-structured interviews of intervention participants, we documented and analyzed process evaluation variables as defined by the Medical Research Council Framework. This study was a stepped wedge trial conducted in Tumbes, Peru in 2014. The intervention was a community-wide replacement of regular salt (100% sodium) with "Salt Liz" (75% sodium and 25% potassium) using social marketing strategies to promote the adoption and continued use of the salt substitute in daily life. The components of the social marketing campaign included entertainment educational activities and local product promoters ("Amigas de Liz"). Another component of the intervention was the Salt Liz spoon to help guide the amount of salt that families should consume. The process evaluation variables measured were the context, mechanism of action, and implementation outcomes (acceptability, fidelity and adoption, perceptions, and feedback).

Results

In total, 60 women were interviewed, 20 with hypertension and 40 without hypertension. Regarding context, common characteristics across the four villages included residents who primarily ate their meals at home and women who were responsible for household food preparation. As the mechanism of action, most participants did not notice a difference in the flavor between regular salt and Salt Liz; those that did notice a difference took around 2 weeks to become accustomed to the taste of the salt substitute. In terms of implementation outcomes, the Salt Liz was accepted by villagers and factors explaining this acceptability included that it was perceived as a "high quality" salt and as having a positive effect on one's health. Participants recognized that the Salt Liz is healthier than regular salt and that it can help prevent or control hypertension. However, most participants could not accurately recall how the compositions of the Salt Liz and regular salt differed and the role they play in hypertension. Although the use of the Salt Liz was far-reaching at the community level, the use of the Salt Liz spoon was poor. Educational entertainment activities were well-received, and most participants enjoyed them despite not always being active participants but rather sideline observers.

Conclusion

This process evaluation identifies key intervention components that enabled a successful trial. Seeking and incorporating feedback from the target population helps deepen the understanding of contextual factors that influence an intervention's success. Furthermore, feedback received can aid the development of the intervention product. Some factors that can be improved for future interventions are acknowledged.

Clinical trial registration

NCT01960972.

Effect of Salt Content Reduction on Food Processing Technology

Higher salt intake is associated with the risk of cardiovascular and kidney diseases, hypertension and gastric cancer. Salt intake reduction represents an effective way to improve people’s health, either by the right choice of food or by a reduction of added salt. Salt substitutes are often used and also herb homogenates are treated by high pressure technology. Salt reduction significantly influences the shelf life, texture, pH, taste, and aroma of cheese. The composition of emulsifying salts or starter cultures must be modified to enact changes in microbial diversity, protease activity and the ripening process. The texture becomes softer and aroma atypical. In bakery products, a salt reduction of only 20–30% is acceptable. Water absorption, dough development, length and intensity of kneading and stability of dough are changed. Gluten development and its viscoelastic properties are affected. The salt reduction promotes yeast growth and CO₂ production. Specific volume and crust colour intensity decreased, and the crumb porosity changed. In meat products, salt provides flavour, texture, and shelf life, and water activity increases. In this case, myofibrillar proteins’ solubility, water binding activity and colour intensity changes were found. The composition of curing nitrite salt mixtures and starter cultures must be modified.

Salt Replacement Changed the Bacterial Community Composition and Physicochemical Characteristics of Sodium-Reduced Fermented Sausages during Fermentation and Ripening

The impact on fermented sausages with 25% replacement of the sodium chloride content by 14% potassium chloride, 10% calcium ascorbate and 1% calcium glutamate during fermentation and ripening was evaluated based on the bacterial community composition and physicochemical and sensory characteristic analysis. Our results showed that the use of salt replacement varied the composition of the bacterial community and reduced the diversity of that in sodium-reduced fermented sausages. Moreover, the decrease in pH and the moisture content of fermented sausages with salt replacement accelerated the drying and ripening processes. The texture profile and color analysis did not reveal marked differences between normal fermented sausages and sodium-reduced products with salt replacement; however, salt replacement reduced resilience and lightness of fermented sausages. In addition, as shown in the principal component analysis, the comprehensive parameters of the fermented sausages with salt replacement were similar to those of normal salt products. These results indicate that the complex blends of salt replacement have great potential to be used to produce sodium-reduced fermented sausages.

Quantification of Process Lethality (5-Log Reduction) of Salmonella and Salt Concentration during Sodium Replacement in Biltong Marinade

Salt (sodium chloride, NaCl) is commonly used in ready-to-eat (RTE) meat products such as biltong, a South African style dried beef product for flavor, enhanced moisture loss, and reduction of microbial growth. However, increased consumption of high sodium content foods is commonly associated with high blood pressure and heart disease. This study evaluated the use of alternative salts, potassium chloride (KCl) and calcium chloride (CaCl₂) in the biltong marinade to achieve a ≥ 5-log reduction of Salmonella, a pathogen of concern in beef products. Beef pieces (1.9 cm × 5.1 cm × 7.6 cm) were inoculated with a five-serovar mixture of Salmonella (Salmonella Thompson 120, Salmonella Enteritidis H3527, Salmonella Typhimurium H3380, Salmonella Heidelberg F5038BG1, and Salmonella Hadar MF60404), vacuum-tumbled in a traditional biltong marinade of salt, spices, and vinegar containing either NaCl, KCl or CaCl₂ (2.2% concentration) followed by an 8-10 day drying period at 23.9 °C (75 °F) and 55% relative humidity. Microbial enumeration of Salmonella was conducted following inoculation, after marination, and after 2, 4, 6, 8, and 10 days of drying in a humidity/temperature chamber. Biltong produced with CaCl₂, NaCl, or KCl achieved a > 5-log reduction of Salmonella after 6, 7, and 8 days, respectively. The Salmonella reduction trends with biltong made with NaCl or CaCl₂ were not significantly different (p < 0.05) while both were significantly different from that made with KCl (p > 0.05). Sodium, calcium, and potassium ion concentrations were measured using ion-specific electrode meters following biltong processing and drying. As expected, the biltong made with the corresponding salt had the most abundant ion in the sample. Regardless of the salt used in the marinade, the potassium ion levels were moderately elevated in all samples. This was determined to be from potassium levels naturally present in beef rather than from other ingredients. Sampling of several commercial brands of biltong for sodium content showed that some were significantly above the allowable level of claims made on package ingredient statements. The substitution of NaCl with KCl or CaCl₂ during biltong processing can also provide a 5-log reduction of Salmonella to produce a safe product that can be marketed as a more healthy low-sodium food alternative that may appeal to consumers who need to reduce their blood pressure and are conscientious of sodium levels in their diet.