The aim of this study was to compare the microbiological quality of cooked sausages produced with a traditional salt content (2.1%) and reformulated batches with a salt content reduced to 1.7%. The reformulation was tested on two types of comminuted meat products – Špekáčky sausage with a diameter of up to 46 mm or Bologna-type sausages in diameter of 85 mm (Gothaj sausage) or 75 mm (Junior sausage). The total viable count (TVC) increased only slightly during the four-week storage (4 ± 1 °C) of all batches of Špekáčky sausage. Comparing batches 1.7 and 2.1, there is an evident difference in the number of CFU/g, with samples of Špekáčky 1.7 showing numbers of bacteria higher by approximately 1 logarithmic order throughout practically the entire storage period (P = 0.001). The population of lactic acid bacteria (LAB) remained well beneath a value of 5.0 log CFU/g even at the end of the experiment. For Bologna-type sausages, the TVC was either beneath the limit of detection or at its boundary in all samples. LAB were not detected during storage of Bologna-type sausages. The results confirmed that the proportion of salt in cooked sausages can be reduced to 1.7% without negatively affecting the shelf life or safety of the final products.
Forty different sample preparation methods were tested to obtain the most informative MALDI-TOF MS protein profiles of pork meat. Extraction by 25% formic acid with the assistance of zirconia-silica beads followed by defatting by methanol:chloroform mixture (1:1, v/v) and deposition by using the layer-by-layer method was determined as the optimum sample preparation protocol. The discriminatory power of the method was then examined on samples of pork meat and meat products. The method was able to discriminate between selected salami based on the production method and brand and was able to monitor the ripening process in salami. However, it was not able to differentiate between different brands of pork ham or closely located parts of pork meat. In the latter case, a more comprehensive analysis using LC-MS/MS was used to assess the differences in protein abundance and their relation to the outputs of MALDI - TOF MS profiling.
Cooking can positively affect meat tenderness, on the other hand, the heat treatment also causes weight loss. The resulting tenderness of cooked meat is influenced by the background toughness of fresh meat, by the post mortem ageing process and by the method of cooking. In the case of heat treatment, the temperature and duration of action play a key role. In this respect, the meat tenderness depends on the type of appliance used for cooking. The cooking loss of meat during heat treatment is caused by contraction of muscle fibres and intramuscular connective tissue, the intensity of which also depends on the temperature and device used. The extent of this contraction increases with increasing temperature. Cooking of meat is considered the most effective way of eliminating microorganisms causing food-borne diseases. The recommended combination of temperature and time of 70 °C for 2 min reduces the number of Listeria monocytogenes bacteria by more than 6 log. This temperature is not, however, always attained with the use of many meat cooking methods, such as grilling or frying. This presents the risk of survival of food-borne agents. The latest knowledge indicates that, in the case of cross contamination, the population of food-borne agents is of the order of 1–2 log CFU/cm2 or g. If they do not multiply as a result of a higher environmental temperature, the population of pathogenic bacteria present is then reliably eliminated during adequate cooking, either entirely or to an amount that does not suffice to induce illness.
The study focused on the effects of traditional (benzoate-sorbate and triphosphates) and alternative (nisin, Laktocid, Defence JB, and Galimax Flavor) food preservatives on the microbiological quality and sensory properties of pasteurized liquid whole eggs (LWE). The LWE samples with the addition of a test preservative and a control were stored at 4°C for 45 D. The selected microbiological parameters, sensory attributes, and color space parameters were determined. The results were statistically analyzed by means of factorial ANOVA, followed by the Tukey post hoc test. The multivariate method of principal component analysis based on the correlation matrix was employed to assess the relationships between pH and sensory characteristics of LWE. Total plate counts at the end of storage differed significantly, being the lowest in samples with benzoate-sorbate (1.69 ± 0.12 log cfu.g-1) and Laktocid (2.12 ± 0.12 log cfu.g-1). The final counts of lactic acid bacteria on day 45 were lower in the samples with benzoate-sorbate, triphosphates, nisin, and Laktocid (maximum 1.01 ± 1.44 log cfu.g-1). The amounts of yeasts at the end of storage did not differ among samples with different preservatives; none were detected in any samples with the exception of Defence JB (1.28 ± 1.90 log cfu.g-1). The lowest final mold count was observed in LWE with Laktocid (0.92 ± 1.29 log cfu.g-1). In conclusion, Laktocid showed great potential as a preservative; it had however a negative impact on pH value and the sensory properties of LWE.
