Challenge tests are a clear opportunity for manufacturers interested in the evaluation of their management system with the aim to reduce the spread of foodborne pathogens. This is a main concern especially in ready-to-eat food in relation to the risk associated with Listeria monocytogenes. For small and medium-scale food industry the manufacturing practices and products formulation are characterised by a wider variability and poor repeatability. The use of ad hoc challenge test and the comparison among different processing systems are strongly required. This paper reports a preliminary comparison among different challenge tests (n=12) commissioned by three manufacturers of raw-fermented salami during a period of three years (2013-2016). The challenge tests were designed to evaluate the growth potential (δ) of L. monocytogenes during the whole processing period of the salami. The doughs were prepared according to different formulations: the simplest formulation was represented by the use of salt, potassium nitrate, black pepper and starter cultures, while the most composited formulations also included the use of sugars and ascorbic acid in addition to nitrite salt. All the processing steps were conducted within an experimental laboratory dedicated for the processing of meat. After stuffing, the salami were dried and ripened under temperature and relative humidity control. The sugar inclusion can be considered as a protective factor, while the drying step at high temperature (above 20°C) was associated with higher δ values (δ>0.5 log10 cfu/g). The addition of starter cultures, and the subsequent acidification highlighted the importance of pH as the parameter able to affect the L. monocytogenes growth.

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Abstract. Due to their role in the formation of secondary aerosol, the concentrations of the most abundant aliphatic amines (methylamine (MA), dimethylamine (DMA), ethylamine (EA), diethylamine (DEA), propylamine (PA), and buthylamine) present in the aerosol of a very anthropized area were measured by an optimized analytical procedure. PM10 samples were collected in the tannery district of Vicenza (in the Po Valley, northern Italy) in autumn 2020. Alkylamines were extracted in water and converted to carbamates through derivatization with Fmoc-OSu for subsequent determination by UHPLC with fluorescence detection. The procedure has been optimized and validated obtaining very satisfactory analytical performances: LODs were in the range of 0.09–0.26 ng/m3, average uncertainty of 3.4 % and recoveries of 95–101 %. The mean total concentration of the 6 amines measured in this study was 37 ± 17 ng/m3, with DMA making the largest contribution. The proposed procedure may contribute to a better characterization of the local aerosol. In our preliminary investigation, the Pearson’s correlation test showed that amines correlate strongly with each other and with secondary inorganic ions (NH4+, NO3- and SO42-), confirming that they compete with ammonia in the acid-base atmospheric processes that lead to the formation of nitrate and sulphate particles. The developed method allows to gather critical information about the load of aliphatic amines in PM to gain more insights into the sources and fate of these chemicals in the atmosphere.