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

Abstract

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.

Afrikaans: Na aanleiding van die onlangse Suid-Afrikaanse regulasies wat die natriuminhoud van verwerkte vleisprodukte beperk, is die mees onlangse weergawe van hierdie regulasies ingespan om vas te stel tot watter mate kommersiële verwerkte vleisprodukte afwyk van hierdie perke en of herformulering benodig word, twee en „n half jaar voordat die eerste verlagingsperke in werking tree. Amper drie jaar voordat die toepaslike etiketregulasies in werking sou tree, is daar bevind dat byna 60% van produketikette reeds natriuminhoud beskryf het. „n Opname van nasionaal en plaaslik beskikbare produkte het dit moontlik gemaak om die vyf grootste produkklasse te identifiseer. „n Daaropvolgende vergelyking tussen etiket en ontleedte natriuminhoud het uitgewys dat vleisverwerkers geneig het om die natriuminhoud as „n voorsorgmatreël te oorskat. „n Ruim speling van 20% vir die onderskatting van die natriuminhoud, soos beskryf in die etiketregulasies, het aangedui dat slegs „n klein aantal produkte op daardie stadium die toekomstige regulasieperke sou oorskry. Spek, polonie en varkwors as verteenwoordigers van die drie grootste klasse is as modelle gebruik om die doeltreffendheid van die tweeledige regulasieperke as intermediêre toegevoegde soutvlakke te evalueer sonder vervangers of veranderinge in verwerking. Wateraktiwiteit, pH en voginhoud is somtyds beïnvloed sonder enige besliste skakels tot afwykings in afhanklike maatstawwe soos mikrobiese stabiliteit. Resultate van mikrobiese en oksidatiewe stabiliteit sowel as sensoriese kwaliteit was bemoedigend. Huidige verwerkingstegnieke en bestanddele anders as NaCl het kwaliteit en stabiliteit gehandhaaf. Veranderinge in spek- en varkworskleur is gevind, alhoewel subjektiewe evaluering nodig is om die implikasies te begryp. Polonietekstuur is kwantitatief en kwalitatief as aanvaarbaar beskou. Totale Na-vlakke wat die regulasieperke beter ewenaar mag die klein afwykings in kwaliteit en stabiliteit verder beperk. Die relatiewe sukses van die gebruik van slegs 1% NaCl (g/g) in die varkwors het aanleiding gegee tot die gebruik van verskeie ander verbindings, beide alleen of in kombinasies, om die gapings in funksie van die verlaagde 1% NaCl aan te spreek. Kaliumchloried (1% g/g), kaliumglukonaat (1% g/g), KCl (0.8% g/g) met gisesktrak (1% g/g) en laastens, KCl (0.8% g/g) met kaliumlaktaat is vergelyk met 1% NaCl (g/g) en 2% NaCl (g/g) kontroles. Behandelings wat KCl bevat het, het kookverliese verbeter teenoor die van die kontroles. Die gebruik van K-bevattende verbindings het die K-inhoud verhoog benewens die verlaging in Na-inhoud. Basiese chemiese maatstawwe was soortgelyk as die van die 2% NaCl kontrole, met slegs die wateraktiwiteit wat meer soortgelyk was as die van die 1% NaCl kontrole. Hierdie vervangers het nie die lipiedstabiliteit verbeter nie, terwyl die gebruik van gisekstrak dit aftief benadeel het. Kleur, as „n multi-komponent kwaliteit maatstaf, was die meeste beïnvloed en verbruikers het minder gunstige hedonistiese reaksies gehad teenoor die gebruik van K-glukonaat. Gedeeltelike vervanging met 1% KCl was die mees geskikte oplossing wanneer verdere faktore soos pryspunt, ooreenkoms met NaCl, en gemak van gebruik in ag geneem is. Laastens is die doeltreffendheid van die verlaging en/of gedeeltelike vervanging van NaCl teen die groei en oorleweing van E. coli en S. aureus wat in varkworsmengsels geïnokuleer is, gemonitor. Op E. coli is geen effekte gevind buite die bakteriostatiese effek van die sub-optimale temperature (4 °C en 10 °C) sowel as die anti-mikrobiese effekte van ander bymiddels in die formulasies nie. Teen verlaagde NaCl vlakke, was S. aureus nie in staat tot groei nie en die oorlewingsyfers het uiteindelik gedaal. Gedeeltelike vervanging het gelei tot beperkte groei, maar oorlewingsyfers het uiteindelik gedaal. Oorlewingsyfers was die hoogste by 1% NaCl, 1% KCl en 0.2% K-laktaat. Suboptimale temperature en ander anti-mikrobiese effekte het die van gedeeltelike NaCl vervanging oorheers. Buiten die aanvanklike inentingsvlakke het verlaging en/of gedeeltelike vervanging van NaCl nie die voedselveiligsrisiko van hierdie bakteriese spesies verhoog nie. Hierdie navorsing het aangetoon dat voldoening aan die regulasieperke „n strategie benodig wat terugneig na die basiese beginsels en dat gebruik gemaak moet word van verskeie benaderings wat beter resultate lewer wanneer hierdie benaderings met mekaar verbind word.