The aim of the study was to investigate the effects of two modified atmospheres with a different combination of gases on selected groups of microorganisms and on concentrations of biogenic amines (BAs) in samples of poultry breast muscle. The samples were packaged under modified atmosphere A (75% O 2 a 25% CO 2 ) or B (75% N 2 and 25% CO 2 ) and stored at temperatures from +2 to +4 °C for 14 days. During the storage period, O 2 concentrations in modified atmosphere A (MA A) decreased from the initial 74.8 ± 0.3% to 55.9 ± 6.6% at the end of the storage period. In all samples, counts of psychrotrophic bacteria counts, Brochothrix thermosphacta, lactic acid bacteria and coliform microorganism were determined. The tests were made on the packaging day, and then after three, nine and fourteen days of storage. At the end of the storage period, higher numbers of psychrotrophic bacteria (6.5 ± 0.7 log 10 cfu·g -1 ), Brochothrix thermosphacta (4.8 ± 0.3 log 10 cfu·g -1 ) and lactic acid bacteria (1.7 ± 0.4 log 10 cfu·g -1 ) were found on samples packaged under MA A. Samples packaged under modified atmosphere B on the other hand contained higher numbers of coliform bacteria (4.1 ± 0.6 log 10 cfu·g -1 ) at the end of the storage period. In addition to microbiological indicators, concentrations of biogenic amines (putrescine, cadaverine, histamine, tyramine, spermine, spermidine and β-phenylethylamine) were also determined. In fresh samples and after three days of storage, only spermine and spermidine were found. After 9 and 14 days, also other BAs were detected. The biogenic amine totals at the end of the storage period was 60.0 ± 13.2 mg·kg -1 in samples packaged under MA A and 129.0 ± 41.3 mg·kg -1 in samples packaged under MA B. The most abundantly represented biogenic amines in samples packaged under MA A were putrescine and spermine (49.7 and 24.8%, respectively, at the end of the storage period), and putrescine and cadaverine in samples packaged under MA B (47.0 and 32.9 %, respectively, at the end of the storage period).

Tománková J., Bořilová J., Steinhauserová I., Gallas L. (2012): Volatile organic compounds as biomarkers of the freshness of poultry meat packaged in a modified atmosphere. Czech J. Food Sci., 30: 395-403.The volatile organic compounds (VOCs) in the packing of chicken meat in a modified atmosphere was qualitatively and quantitatively evaluated. The total number of 72 samples of chicken hindquarters were stored under two different modified atmospheres (70% O 2 , 30% CO 2 , and 70% argon, 30% CO 2 ) for 20 days. Analyses were performed on Days 0, 4, 8, 12, 16, and 20. VOCs in the headspace samples were detected and quantified by gas chromatography/mass spectrometry (GC/MS) every fourth day of storage. Pentamethylheptane, dimethylsulphide, dimethyl disulphide, dimethyl trisulphide, dimethyl tetrasulphide, hydrogen sulphide and ammonia were detected. Pentamethylheptane and ammonia had similar values for both modified atmospheres (MA). The other compounds were found only in argon MA from the Day 16 of storage with a subsequent increase of values. The measured values for dimethylsulphide were 10.7 and 13.8 mg/l, for dimethyl disulphide they were 1.9 and 10.7 mg/l, dimethyl trisulphide levels were 15.7 and 19.3 mg/l and dimethyl tetrasulphide levels were 93.2 and 418.3 mg/l for Day 16 and 20. The hydrogen sulphide level was detected from 80 to 370 mg/l after the 8 th day of storage. We showed that the argon MA is less suitable for packaging raw chicken parts than the oxygen MA in view of the increased amount of microflora and unpleasant odour as assessed by sensory analysis. Oxygen prolonged the shelf life by about four days in comparison with argon. Sensory evaluation was similar for both atmospheres after air exhaustion. The argon MA did not extend the shelf life as compared to the oxygen MA.

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The objectives of this study were to develop calibration models for determination of water activity and the content of fat, dry matter, salt, non collagen muscle protein and pH in dry cooked sausages. Samples (n = 42) were scanned in FT-NIR Analyzer and simultaneously analyzed by standard methods. The spectra were measured in the reflectance mode with a compressive cell between 10 000 and 4 000 cm -1 , averaging 100 scans. Calibration models were developed using the partial least squares (PLS) method. These calibration models were checked later by crossvalidation. The following statistical values were obtained: R (correlation coefficient) = 0.997 and SEC (standard error of calibration) = 0.002 for water activity, R = 0.966 and SEC = 0.023 for pH, R = 0.995 and SEC = 0.970 for dry matter content, R = 0.995 and SEC = 0.045 for salt content, R = 0.965 and SEC = 0.652 for non collagen muscle protein, R = 0.996 and SEC = 0.559 for fat content. The results of the study showed that FT-NIR is a suitable method for rapid analysis of physical and chemical properties of sausages. FT-NIR, spectroscopy, calibration models, sausagesFourier Transform Near Infrared (FT-NIR) spectroscopy has been a success in the chemical analysis industry thanks to a number of advantages, as it is a rapid and exact method. In the dairy industry, spectroscopy in the infrared region is used for assessing lactose, protein and fat contents in milk. It is also used in the cereals and feedstuffs producing industries. It has been shown in the course of the last three decades that NIR is also a very efficient and promising method for the assessment of meat and meat product quality (Prieto et al. 2006;Ripoll et al. 2008).Advanced countries face a high demand for meat and meat products that are appreciated by consumers as valuable nutritional components. In order to keep the standard quality of meat products required by the consumers, it is necessary to carry out a series of quality checks. Various assays are commonly used to assess meat and meat product quality when evaluating their physical, chemical, microbiological and sensory properties. The traditional methods are, however, very time-consuming and, as a result, unusable in the production line analysis (Liu et al. 2004). In comparison with conventional methods for assessing meat indicators, near infrared spectroscopy is a sensitive, rapid and non-destructive analytical technique with a simple sample preparation and it allows for simultaneous assessment of several variables (Prieto et al. 2006). NIR spectroscopy is successfully applied when assessing the quantities of the main components (water, fats and proteins) in meat and meat products (Prevolník et al. 2004;Berzhaghi et al. 2005;Gaitan-Jurado et al. 2008;Prieto et al. 2006;Viljoen et al. 2007).The goal of this project was to create calibration models for assessing the important physical and chemical properties of quality in dry cooked sausage "Vysočina", namely in the following areas: water activity, pH, dry matter content, salt content,...