The effect of sodium reduction on the chemical, microbial and sensory quality of prominent South African processed meat products

English: In light of the recent South African regulations limiting the sodium content of processed meat products, the latest draft of these regulations were used to establish to what extent commercial processed meat products deviated from these limits and required reformulation, two and a half years in advance of the first reduction limits coming into effect. Almost 60% of product labels already included information on sodium content almost three years before the applicable labelling regulations came into effect. Surveying nationally and regionally available products allowed for the identification of the five largest product classes. A comparison between labelled and determined Na content revealed that processors tended to overestimate Na content as a precautionary measure. A generous tolerance of 20% for underestimating the Na content, as stated in the labelling regulations draft, showed that only a small number of products would at the time, have exceeded the futuredated regulatory limits. Bacon, polony and pork bangers, representing the three most populous classes were used to evaluate the efficacy of the two-part regulatory limits as intermediate added NaCl levels without replacers or alterations in processing. Water activity, pH and moisture content were inconsistently affected with no definite links to deviations in dependent parameters such as microbial stability. Microbial and oxidative stability and sensory quality results were encouraging. Current processing techniques and ingredients other than NaCl maintained quality and stability. Changes in bacon and banger colour were found, although subjective evaluation is needed to grasp the implications. Polony texture was deemed acceptable, both quantitatively and qualitatively. Total Na levels better matching the regulatory limits may further limit the minor deviations in quality and stability. The relative success of using only 1% NaCl (w/w) in the pork bangers prompted the use of various compounds, either alone or in combination, to address the gaps in functionality of the 1% NaCl removed from the original formulation. Potassium chloride (1% w/w), K-gluconate (1% w/w), KCl (0.8% w/w) with YE (1% w/w) and lastly, KCl (0.8% w/w) with K-lactate (0.2% w/w) were compared to 1% NaCl and 2% NaCl controls. Treatments containing KCl had improved cooking losses over that of the controls. The use of K-containing compounds increased the K-content in addition to reducing Na-content. Basic chemical parameters were similar to that of the 2% NaCl control with only water activity being more similar to that of the 1% NaCl control. These replacers did not improve lipid oxidative stability and the use of YE actively deteriorated lipid oxidative stability. Colour was the most affected multi-component parameter and consumers had less favourable hedonic responses towards the use of K-gluconate. Partial replacement with 1% KCl was the most suitable solution when additional factors such as price-point, similarity to NaCl, and ease-of-use were taken into account. Lastly, the efficacy of the reduction and/or partial replacement of NaCl against the growth and survival of E. coli and S. aureus inoculated into banger batters were monitored. No effects on E. coli were observed beyond the bacteriostatic effect of sub-optimal temperatures (4 °C and 10°C) and the anti-microbial effects of the other additives in the formulations. At reduced NaCl levels, S. aureus was unable to grow and survival rate ultimately decreased. Partial replacement led to limited growth although survival rates eventually decreased. Survival rates were highest at 1% NaCl, 1% KCl and 0.2% K-lactate. Sub-optimal temperatures and other anti-microbial effects overrode that of partial NaCl replacement. Beyond the initial inoculation levels, reduction and/or partial replacement of NaCl did not increase the food safety risk of these bacterial species. This research showed that conformation with the regulatory limits warrants a back-to-basics strategy using multiple approaches that deliver better results when these approaches are linked to one another.