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

[摘要] English: In light of the recent South African regulations limiting the sodium content of processed meatproducts, the latest draft of these regulations were used to establish to what extent commercialprocessed meat products deviated from these limits and required reformulation, two and a half yearsin advance of the first reduction limits coming into effect. Almost 60% of product labels alreadyincluded information on sodium content almost three years before the applicable labellingregulations came into effect. Surveying nationally and regionally available products allowed for theidentification of the five largest product classes. A comparison between labelled and determined Nacontent revealed that processors tended to overestimate Na content as a precautionary measure. Agenerous tolerance of 20% for underestimating the Na content, as stated in the labelling regulationsdraft, showed that only a small number of products would at the time, have exceeded the futuredatedregulatory limits.Bacon, polony and pork bangers, representing the three most populous classes were used toevaluate the efficacy of the two-part regulatory limits as intermediate added NaCl levels withoutreplacers or alterations in processing. Water activity, pH and moisture content were inconsistentlyaffected with no definite links to deviations in dependent parameters such as microbial stability.Microbial and oxidative stability and sensory quality results were encouraging. Current processingtechniques and ingredients other than NaCl maintained quality and stability. Changes in bacon andbanger colour were found, although subjective evaluation is needed to grasp the implications.Polony texture was deemed acceptable, both quantitatively and qualitatively. Total Na levels bettermatching 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 variouscompounds, either alone or in combination, to address the gaps in functionality of the 1% NaClremoved 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) werecompared to 1% NaCl and 2% NaCl controls. Treatments containing KCl had improved cookinglosses over that of the controls. The use of K-containing compounds increased the K-content inaddition to reducing Na-content. Basic chemical parameters were similar to that of the 2% NaClcontrol with only water activity being more similar to that of the 1% NaCl control. These replacersdid not improve lipid oxidative stability and the use of YE actively deteriorated lipid oxidativestability. 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% KClwas the most suitable solution when additional factors such as price-point, similarity to NaCl, andease-of-use were taken into account.Lastly, the efficacy of the reduction and/or partial replacement of NaCl against the growth andsurvival 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 limitedgrowth 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 ofpartial NaCl replacement. Beyond the initial inoculation levels, reduction and/or partial replacementof 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-basicsstrategy using multiple approaches that deliver better results when these approaches are linked toone another.

[发布机构] University of the Free State