The influence of nitrite and nitrate on microbial, chemical and sensory parameters of slow dry fermented sausage Aurora Marco, Jose ´ Luis Navarro, Mo ´ nica Flores * Instituto de Agroquı ´mica y Tecnologı ´a de Alimentos (CSIC), Apartado 73, 46100 Burjassot (Valencia), Spain Received 12 August 2005; received in revised form 8 March 2006; accepted 10 March 2006 Abstract Nitrate and/or nitrite are used in the manufacture of dry-fermented sausages. However, research has mainly been focusing on nitrite and its effect on flavour development whereas little attention has been paid to nitrate. The aim of the present work was to study the effect of nitrate and nitrite as curing salts on the quality of a slow fermentation process. Two different batches containing nitrate or nitrite were manufactured. Microbial and chemical parameters were monitored during ripening and after vacuum packed storage, as well as their fatty acid composition and their profile of volatile compounds. The oxidation, measured as TBARS (Thiobarbituric acid reactive sub- stances), was greater in the samples with added nitrite than in the samples with added nitrate. FFA (free fatty acids) release was higher in the samples containing nitrite throughout the process. Volatile compounds arising from amino acid degradation and carbohydrate fer- mentation were generated at higher levels in the samples with added nitrate, probably due to the higher population of microorganisms in these samples and the effect of nitrate on their metabolism. Ó 2006 Elsevier Ltd. All rights reserved. Keywords: Aroma; Curing; Dry-fermented sausage; Fatty acid composition; Nitrite; Nitrate 1. Introduction Curing is a conservation technique widely used since antiquity to prolong the shelf-life of food products. Pres- ently, rapid curing processes are being used in the manufac- ture of dry cured sausages allowing the meat industry to reduce the costs associated with a long curing process. However, rapid curing results in the loss of the typical orga- noleptic characteristics in the final product, especially with regard to the aroma and taste (Flores & Bermell, 1996). Curing processes are different in the different European regions (Flores, 1997). In Northern Europe, the curing pro- cesses are short, using only nitrite as curing agent, coupled with smoking of the products. By contrast, in the Mediter- ranean area longer curing times are used, involving both nitrite and nitrate as curing agents and without smoking process. A high intake of nitrite presents a risk to human health due to possible allergenic effects, vasodilator effects, met- myoglobin production in vivo and the production of car- cinogenic nitrosamines (Cammack et al., 1999). Due to this biological hazard, some governments have asked the European Food Safety Authority (EFSA, 2003) to reduce the permitted amounts of nitrite and nitrate. No risk is associated with the ingestion of nitrate other than those arising from reduction to nitrite by intestinal bacteria. It should be pointed out that some vegetables have natural quantities of nitrate 10 times higher than the amounts allowed for meat products. Also, due to the low pH and small amounts of nitrite and nitrate added to cured meat products and the lack of heat treatment, the risk of nitros- amines production is minimal (Honikel, 2005). The effects of nitrite in cured products have been studied for many years and can be summarised as: formation of the characteristic red colour; growth inhibition of spoilage and pathogenic bacteria such as Clostridium botulinum; contri- bution to the development of typical cured meat flavour; 0309-1740/$ - see front matter Ó 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.meatsci.2006.03.011 * Corresponding author. Tel.: +34 96 3900022; fax: +34 96 3636301. E-mail address: mflores@iata.csic.es (M. Flores). www.elsevier.com/locate/meatsci Meat Science 73 (2006) 660–673 MEAT SCIENCE