MODEL TO CALCULATE THE ENVIRONMENTAL, NUTRITIONAL AND ECONOMIC STATUS OF MILK AND PLANT-BASED BEVERAGES.

Because of increased awareness of environmental impacts, the dairy industry has come under scrutiny, resulting in alternative plant-based products being developed; the assumption being that these products have a lesser environmental impact. However, when consulting the literature, the environmental and nutritional attributes of these products are poorly understood. Also, despite the critical role of bovine milk in diets worldwide, the environmental, nutritional and economic constituents of sustainability have not been comprehensively compared to the plant-based beverages of these products. The literature shows that existing sustainability metrics are often generalised to all products or contexts, thereby limiting informed decisions by producers, policymakers and consumers. As a result, there is a need to understand the environmental, economic and nutritional implications of milk and plant-based beverages in the local context, but also globally, to support sustainable decision-making. Therefore, a study by the authors cited was commissioned by Milk SA to develop a comprehensive sustainability model tailored to milk and plant-based beverages, which should focus on the environmental, economic and nutritional dimensions. This model should then provide a practical tool for assessing and comparing key sustainability indicators as they play out under different production systems and circumstances.

The methodology used was firstly to do an extensive literature review to identify key indicators, domains and existing methods to be included in the model. A further literature review followed to gather data on key indicators to populate the model. To test the model, both primary and secondary data were sourced by means of (1) nutritional analyses on local milk and the plant-based beverages soy, almond and oats, (2) factory tours and data collection, and (3) further literature investigations, based on the experience of (1) and (2). The values obtained for each of the products were combined to compile comparisons and test the applicability and accuracy of the model. The model itself was tailored to develop a nutritional index for milk and the plant-based beverages, incorporating methodologies such as the Nutrient-Rich Food Index (NRFi), demographically stratified age and sex-specific dietary needs, global nutrient contributions, associations with diseases or protective effects, and protein quality. In the environmental sphere, the approach used life-cycle analysis (LCA) principles adapting to readily measurable parameters within farming and production systems, including water use, fertilizer application, land use, energy consumption, recyclable materials, waste management, or LCA results. The approach also employed consumer and producer indicators as well as self-reported inquiries on aspects such as employee numbers, production efficiencies, profitability and others, which were considered along with product pricing in relation to country-specific poverty levels.

A summary of the results is shown in the table in index format.

Sustainability indicator scores in general, and specific to the carbon footprint.

^NRFPi: Nutrient Rich Food Price Index = Nutrient density score per Rand spent

*NRFPi/CO₂ eq = Nutrient density score achieved per Rand for each kg of carbon dioxide emitted

**CO₂ eq/NRFPi = kg carbon dioxide emitted per Rand spent to achieve nutrient density score

For the individual sustainability components, the results in the table show that bovine milk expressed the most favourable nutritional and economic profile, while the environmental score was within the ranges of the plant-based beverages. The nutritional score is based on chemical analyses, nutritional requirements and malnutrition parameters which are specific, and will therefore have little variation. The environmental score was obtained as an index including water use, land use, energy and nitrogen use, greenhouse gas emissions (GHGE) and others. These are all cite (farm) specific and depends on the production system followed. The same applies to the economic score. For the development of the model a specific scenario and production process were chosen, but the reader should realize that due to considerable variation in the elements included in the environmental and economic scores, the outcomes may vary substantially. This variation is illustrated where GHGE is expressed relative to NRFPi (to express emission justification in relation to food security) and per monetary unit spent. For the average scenario though, bovine milk achieved the highest nutrient density score per Rand for each kg of carbon dioxide emitted, or reciprocally, the least carbon dioxide emitted per Rand spent to achieve the required nutrient density score.