2.?Experimental2.1. Sample preparation and samplingTwo different types of meat species representative of Moroccan production and purchased www.selleckchem.com/products/MG132.html from a local market were analysed. The samples from different animal species (beef and sheep) were cut into pieces of the same weight (10 g �� 1 g) immediately after receiving, placed Erlotinib clinical Inhibitors,Modulators,Libraries in plastic bags (bags for freezing food) and introduced in a refrigerator kept at a constant temperature of 4��C �� 1��C. For each measurement, a meat sample was taken from the refrigerator and put inside a 500 ml glass bottle. The sampling bottles were sealed with septum and held at room temperature (22��C �� 2��C) for 50 min in order to reach a stable composition of the headspace. Measurements were performed each day for up to 2 weeks.

Inhibitors,Modulators,Libraries Every day Inhibitors,Modulators,Libraries two replicate samples were withdrawn from the Inhibitors,Modulators,Libraries refrigerator to undergo microbiological analysis and six replicate samples were employed for electronic nose analysis. This procedure was repeated with the two types of red meats under investigation.2.2. Microbiological population enumerationA 25 g sample of each product was taken aseptically and placed in a sterile stomacher bag containing 225 ml of 0.1 % (wt/vol) peptone water (PW, Oxoid Ltd., Hampshire. England). The sample and the PW were stomached for 2 min. Decimal dilutions were prepared using the same diluent. Inhibitors,Modulators,Libraries These dilutions were subsequently plated on the surface of a Plate Count Agar (PCA, Oxoid Ltd.). The plates were incubated at 30 ��C for 2 days.

The total viable counts (TVC) were obtained Inhibitors,Modulators,Libraries by enumerating the colonies Inhibitors,Modulators,Libraries present, and calculated as log10 colony forming units (cfu)/g of the sample.

2.3. Electronic nose systemAn electronic nose Carfilzomib system was employed to obtain the smell patterns from the headspace of meat samples (Fig. 1). Inhibitors,Modulators,Libraries This electronic nose system contains an array of six tin oxide based Taguchi gas sensors obtained from Figaro Engineering, a temperature sensor (National Semiconductors LM35DZ), and humidity sensor (PHILIPS H1). The identification codes of the Figaro sensors that were used are as follows (their target gases, as suggested by the manufacturer, are also indicated): TGS 823 (Alcohols, Xylene and Toluene), TGS 825 (H2S), TGS 826 (NH3), TGS 831 (Chlorofluorocarbons), TGS 832 (Halocarbons) and TGS 882 (Alcohols) [14].

The TGS sensors from the 8 series have been used by other authors Anacetrapib in the quality control of red meats [13].

These sensors, which are based on tin oxide doped with noble metal catalysts show good responsiveness to acetone, and nitrogen and sulphur compounds, which have been suggested as spoilage indicators for read meat [4, 7, 8]. Full details on the electronic nilotinib mechanism of action nose system implemented here can be found elsewhere [15].Figure 1.Schematic of the experimental set-up.In a typical measurement, the headspace from a meat sample is fluxed selleck screening library into the electronic nose sensor chamber.