Sodium nitrite versus vegetable extract: effectiveness against Listeria monocytogenes

Summary of a presentation of 44. Kulmbacher week 2009

Raw sausage products are only stabilized through a suitable fermentation process. The sequence and conditions of this process as well as additives and the quality of the raw materials ultimately determine the safety of the end product. The raw material (pork or beef) for the production of raw sausage products can be contaminated with various pathogens. Nitrite or nitrate is added to raw sausages to preserve and inhibit the growth of such undesirable germs. Nitrate is mainly used here in long-matured products. In such products, nitrate is converted to nitrite through chemical or microbiological reactions. Since these processes take place slowly but continuously, nitrite can develop its positive effects over a longer period of time.

The positive effects of nitrite are reddening, aroma formation, preservation and protection against oxidation. An undesirable aspect, however, is the reaction of nitrite with protein components in foods to form potentially carcinogenic nitrosamines.

Chemical additives are generally less accepted by consumers than plant-based ingredients (e.g. spices, vegetable extracts). Sausages reddened with spice and vegetable extracts can be declared as "preservative-free", even though they contain e.g. T. have a high nitrate content and can therefore also contribute to the formation of nitrosamines.

The safety of such products cannot be adequately assessed at present, as there have been no corresponding scientific studies to date.

The aim of the project was therefore to examine the behavior of the dying kinetics of Listeria monocytogenes in a sliceable raw sausage product that was produced without the addition of nitrite. For this purpose, the original recipe with vegetable extract (0,5%) was compared with a recipe with nitrite curing salt (0,4 - 0,5%).

The investigations showed that the addition of a vegetable extract had no antimicrobial effect on the microorganisms used. An increase in pathogenic germs in the products made with vegetable extracts cannot be ruled out. The omission of the addition of sodium nitrite therefore entails a risk that is particularly present if the raw materials are contaminated with Listeria monocytogenes.

The lecture provides information about the results of these studies and makes it clear to what extent the renunciation of nitrite curing salt is justified without increasing the microbial risk.

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The lectures of the Kulmbach Week are fully documented in the newsletter of the sponsoring society for meat research in Kulmbach.

The newsletter is issued by the meat research association in Kulmbach and sent to the members free of charge. The sponsoring company uses substantial funds that are used for the research work of the MRI, Kulmbach location.

More details at www.fgbaff.de

Source: Kulmbach [ KABISCH, J., R. PICHNER, HG HECHELMANN and M. GAREIS ]