Comparison of Situation in the Slovak and Czech Market of Milk and Dairy Products

The paper is focused on dairy sector with the emphasis on the development of consumption of milk and dairy products, including cheese, curd and other dairy products, in the last 15 years in the Slovak Republic and in the Czech Republic. The aim of the paper is to identify the level of milk and dairy products consumption, as well as to identify the main determinants affecting the consumption. Paper is also aimed at milk production with emphasis on the main problems that may affect future development on the dairy market. The primary data are obtained by consumer survey and survey aimed focused on producers of milk and dairy products. Based on the results we have identified that the milk and dairy products consumption by Slovak consumers is lower compared to the Czech Republic and the quality and price are considered as the main determinants influencing the consumption. We also found out that milk and dairy products producers are adapting their production to demand, but it is important to point out the barriers related in particular to the introduction of new technologies into production, rising input prices or growing consumer disinterest in the consumption of milk and dairy products.

Front-Face Fluorimeter for the Determination of Cutting Time of Cheese Curd

The yield of product (cheese) during the cheese-making process depends on the cutting time of the cheese curd. However, the determination of optimal cutting time on an industrial scale is difficult as current standard methods are destructive or analyse only small volumes and not the entire milk to be curdled into cheese. This paper presents a novel front-face fluorimeter (FFF) that is designed to be immersed into a milk batch to enable the determination of the cutting time of cheese curd without the destruction of the sample. The FFF sensor signal corresponds to physical changes in milk during cheese formation and has high predictive power (r > 0.85) and good accuracy (RSE = 30%, considering daily variation between milk samples). The performance of the presented fluorimeter was on par with standard rheological and Berridge methods.

Transcripts and protein levels of CSN1S1 and CSN3 genes in dairy cattle mammary gland secretory tissue during chronic staphylococcal infection

Our objective was to determine the influence of chronic coagulase-positive staphylococci (CoPS) or coagulase-negative staphylococci (CoNS) infection on the mRNA and protein levels of two main milk proteins responsible for cheese curd quantity and quality, alpha-S1-casein (CSN1S1) and kappa-casein (CSN3). Measurements were made in cow mammary parenchyma with a prevalence of secretory tissue (MGST). Samples of MGST were collected from the separate quarters and divided into CoPS, CoNS and bacteria-free (H) groups according to the microbiological status of the quarter milk. No differences in CSN1S1 and CSN3 mRNA level were found between groups, however, CSN1S1 protein level was significantly higher in the H group than the CoNS group, and CSN3 protein level was significantly higher in H than CoPS group. Hence, while the CSN1S1 and CSN3 genes appear to be constitutively expressed at the mRNA level in dairy cow MGST during mastitis, CoNS infection negatively affected CSN1S1 protein level, and CoPS infection negatively affected CSN3 protein level. The lack of change at the mRNA level suggests that staphylococcal infection may affect the post-transcriptional or post-translational modifications.

Heat Resistance of Listeria monocytogenes in Dairy Matrices Involved in Mozzarella di Bufala Campana PDO Cheese

The presence of Listeria monocytogenes in Mozzarella di Bufala Campana Protected Designation of Origin cheeses may depend on curd stretching conditions and post contaminations before packaging. To avoid cross-contamination, thermal treatment of water, brines and covering liquid may become necessary. The present study aimed to improve knowledge about L. monocytogenes thermal resistance focusing on the influence of some cheese making operations, namely curd stretching and heat treatment of fluids in contact with cheese after molding, in order to improve the safety of the cheese, optimize efficacy and sustainability of the processes. Moreover, the role that cheese curd stretching plays in L. monocytogenes inactivation was discussed. The 12 tested strains showed a very heterogeneous heat resistance that ranged from 7 to less than 1 Log10 Cfu/mL reduction after 8 min at 60°C. D-values (decimal reduction times) and z-values (thermal resistance constant) calculated for the most heat resistant strain among 60 and 70°C were highly affected by the matrix and, in particular, heat resistance noticeably increased in drained cheese curd. As cheese curd stretching is not an isothermal process, to simulate the overall lethal effect of an industrial process a secondary model was built. The lethal effect of the process was estimated around 4 Log10 reductions. The data provided may be useful for fresh pasta filata cheese producers in determining appropriate processing durations and temperatures for producing safe cheeses.

Application of Enterococcus faecium KE82, an enterocin-A-B-P-producing strain, as an adjunct culture enhances inactivation of Listeria monocytogenes during traditional PDO Galotyri cheese processing

The ability of the enterocin-A-B-P-producing Enterococcus faecium KE82 adjunct strain to inactivate Listeria monocytogenes during Galotyri PDO cheese processing was evaluated. Three artisan cheese trials from traditionally ‘boiled’ (85oC) ewe’s milk were processed. The milk cooled at 42oC was divided in two parts: A1 was inoculated with Streptococcus thermophilus ST1 and Lactococcus lactis subsp. cremoris M78, and A2 with the basic starter ST1+M78 plus the KE82 adjunct (step 1). All milks were fermented at 20-22oC for 24 h (step 2); the curds were drained at 12oC for 72 h (step 3) and then salted with 1.5-1.8% salt to obtain the fresh Galotyri cheeses (step 4), which were ripened at 4oC for 30 days (step 5). Because an artificial listerial contamination in the dairy plant was prohibited, A1 and A2 cheese milk (200-mL) or curd (200-g) portions were taken after steps 1 to 5, inoculated (3-4 log CFU/mL or g) with L. monocytogenes no.10, incubated at 37, 22, 12, and 4oC for predefined periods, and analyzed microbiologically and for pH. L. monocytogenes declined without growth in all cheese curd portions contaminated after steps 2 to 5 (pH 4.36 to 4.84), when stored at 4 or 12oC for 15 days. The final net reductions of Listeria populations were by 2.00, 1.07, 0.54 and 0.61 log units higher in the A2 than A1 curd portions after steps 2, 3, 4 and 5, respectively. As regards step 1 conducted in simulation of the whole cheese milk fermentation process, L. monocytogenes declined by 1.47 log units more in the A2 than A1 milk portions after 72 h at 22oC; however, a slight (0.6-log) growth was preceded during the first 6 h at 37oC. In conclusion, E. faecium KE82 showed growth compatibility with the starter and enhanced inactivation of L. monocytogenes across Galotyri cheese processing. Combined acid-enterocin antilisterial effects were the weakest in the fermenting milks, turned to the strongest in the unsalted fermented curds, and reduced in the salted fresh cheeses.

Identification and Pathogenic Potential of Bacillus cereus Strains Isolated from a Dairy Processing Plant Producing PDO Taleggio Cheese

Low levels of contamination by Bacillus cereus at the cheese farm is essential for reducing any opportunity for growth prior consumption. In this study, B. cereus distribution in a plant producing Protected Designation of Origin Taleggio cheese was investigated and the virulence potential of the isolates was evaluated. Seventy-four samples were collected from Food and Non Food Contact Surfaces (FCS, NFCS), saline curd, and Taleggio. The eleven isolates were identified, typified, and clustered. Strains were tested for the production of hemolysins, hemolysin BL (HBL), phosphatidylcholine-specific phospholipase C (PC-PLC), proteases, and biofilm, and for the presence of chromosomal toxin-encoding genes (sph, plcA, cytK, entFM, bcet, entS, nheA, nheB, nheC). B. cereus was detected on NFCS, FCS, and curd, but not in Taleggio. The isolates were grouped into six clusters, and all produced PC-PLC, hemolysins, and proteases, and most of them HBL (66.7%). All the clusters harbored the nheA, sph, plcA, entFM, and cytK genes, and some also nheB (83.3%), nheC (66.7%), bcet (50.0%), and entS (66.7%). All strains showed biofilm-forming ability. Our data reveal possible contamination of production plants and cheese curd by potentially virulent B. cereus, but bacterial absence in Taleggio highlights the efficacy of a proper management of the production phases in assuring consumer’s protection.

Justification of express technology in the «Pasta Filata» group cheese production

The most common one of the «Pasta Filata» group is «Mozzarella», a soft Italian cheese that is now made from cow's milk and widely used in many dishes, especially as a pizza topping, which is the most popular food for young people. The paper substantiates the express technology for the production of soft cheese like «Mozzarella». The first batch of Mozzarella-type soft cheese was made using traditionally accepted technology. Another batch of cheese samples was made using express technology. In contrast to traditional technology, an aqueous solution of citric acid was added to the normalized mixture before making the main components, thereby instantly increasing the active acidity, which reduced the duration of the cheddarization process of the cheese mass. Other technological operations were similar to traditional technology. The research results show that during the production of experimental batches of cheese at the stage of cheese curd formation, the milk coagulation process in the samples obtained by traditional technology took an average of 42,3 min ± 1,45 min, whereas in the samples of experimental batch № 2, this process was much faster, only 15,7 min ± 2,40 min by adding an aqueous citric acid solution. The research results have established that the production of the soft cheese type «Mozzarella» by express technology leads to the reduction of the technological process, namely to decrease (by 9 times) the duration of cheddarization of the cheese mass which produces the necessary consistency (pH 5,3-5,2) for the further melting and stretching the cheese dough. The output of the finished product under the various technologies of production of soft «Mozzarella» cheese was almost at the same level. Thus, the weight of cheese of experimental batch № 1 on average was 829 g ± 12,66, respectively, the mass of cheese of batch № 2 - 847 g ± 14,36. The tasting assessment on a point scale showed that all tested cheese lots, regardless of the production technology had rather high points (41.8-42.0) and had perfect organoleptic characteristics that are typical for the type of cheese understudy and meets the standard requirements. In general, the analysis of these studies showed that the production of soft cheese, such as «Mozzarella» by the express technology, namely the use of citric acid leads to a minimal time of the cheddarization process. Reduces the clotting time of milk and the formation of the cheese mass of the necessary consistency for further melting and extraction, which in turn causes the technological process of production of the finished product to be reduced altogether.

Technological Aspects of Cold Storage of Protein Dairy Products

The dairy market is currently evolving very fast, and the cooperation between countries is developing. As a result, the most popular dairy products are those with better storage stability. In this regard, one of the main tasks of the producers is a year-round supply of high-quality dairy products. Refrigeration is the most effective, environmentally safe, and affordable way of preserving food. Low temperature of minus 20°C increases the shelf life of cottage cheese, curd products, and cream cheeses, preserves their quality, and reduces the microbiological risks. The present research features the specifics of cold storage of protein dairy products at chilled, subfrozen, and frozen modes. The experiment involved a multiple freezing unit. The authors studied the organoleptic and physico-chemical indicators of multi-component dairy products based on processed and cottage cheeses that were fortified with plant material (cranberries, nettle, ramson, sorrel, wild rose, etc.) during prolonged storage. The taste and composition of dishes based on the dairy products mentioned above were assessed by panelists. The quality indicators helped to establish the best terms and conditions for fridge storage of the protein dairy products in question.