Impact of coffee silverskin on in-vitro viability of kefir culture during storage

Probiotic dairy products must contain a certain level of live probiotic microorganisms at the time of consumption. The number of live microorganisms in kefir culture, which is a mixture of different microorganisms, may change during storage due to various factors. In this study, the effects of adding a novel ingredient coffee bean membrane (CSS-coffee silverskin), on the viability of microorganisms contained in kefir culture were investigated. For this purpose, CSS obtained from 2 different coffee varieties (Arabica and Robusta) was added to kefir samples at 3 different concentrations (0.5, 0.75 and 1.0 %) at the beginning of fermentation. It was observed that especially the addition of CSS belonging to the Robusta variety significantly increased the viability of lactic acid bacteria (lactobacilli and lactococci) which accounted for 88-94.10 % and 82.37-92.44 % respectively. During the storage period of 28 days at 4 °C; it could be observed that kefir enrichment with CSS of both coffee varieties increased the viability of lactobacilli and lactococci after in-vitro digestion, depending on the rate of supplementation. Number of yeasts was decreased during the storage.

The use of the two different mycotoxin deactivators in the nutrition of dairy cows

The aim of this study was to investigate the effect of two different commercial products for mycotoxin deactivation in the dairy cows’ nutrition. The research was done on the 18 dairy cows in the different phase of lactation, with the average production of 14 L of milk per day. The diet contained in average 8 kg of concentrate feed, 10 kg of mixed peas and wheat forage, 4 kg hay of alfalfa and cereal straw ad libitum. Before starting the trials all components of the cows’ ration were analysed for the presence of aflatoxin B1, while cow’s milk was analysed for the presence of aflatoxin M1. In the first phase of the trial cows were fed diet containing aflatoxin B1 at level of 5±0.9 µg/kg, which resulted in the average aflatoxin M1concentration of 181±3.5 ng/kg in the milk. In the second phase of the trail 0.5 % of the commercial product 1 (Neozel®) was added into the feed ration of cows and after the period of adaptation, the aflatoxin M1 concentration in milk was measured. In the third phase of the trail 0.3 % of the commercial product 2 (miko-Stop 0.3®) was added into the feed ration of cows and also, after the period of adaptation, the concentration of aflatoxin M1 in milk was measured. The last phase was the control phase in which cows were fed diets with aflatoxin B1 (5 µg/kg) without added mycotoxin deactivators. The use of both commercial products for ten days resulted in the reduction of aflatoxin M1 levels for 35.9 % and 53.6 %, respectively.

The influence of crossbreeding and LPL genotype on the yield, composition and quality of goat milk

The aim of this study was to investigate the influence of crossbreeding and the LPL genotype on goat milk yield, composition and quality indicators. This research was carried out in a herd of pure-breed Saanen, Anglo-Nubian, and crossbred Saanen and Anglo-Nubian goats (n=137) in Lithuania. Saanen x Anglo-Nubian crossbred goats and Saanen had a significantly (P<0.05) higher (34.91% and 16.03 %, respectively) milk yield compared to Anglo-Nubian goats. The highest (P<0.05) fat and protein and the lowest (P<0.05) lactose percentages and somatic cell count were found in the milk of Anglo-Nubian goats, compared to Saanen x Anglo-Nubian crossbreds and Saanen goats. The highest (P<0.05) milk yield was determined in the CC genotype of the LPL gene (on average 20.08 % higher than in the CG and GG genotypes) of goats. However, the milk yield of the CC genotype was characterised (P<0.05) by the lowest fat, protein and milk urea levels, and the highest amount of lactose compared to the milk of the GG genotype. The study showed that breed and LPL genotype affected goat milk yield and composition and appear to be the valuable biomarkers of the goat selection process.

Consumers’ attitudes, motives and behaviour towards organic yoghurt in Croatia

The organic food market is constantly growing, while organic yoghurt belongs to the category of the best-selling organic products in the dairy products group. The aim of this study was to determine consumer behaviour in the purchase and consumption of organic yoghurt, attitudes concerning organic yoghurt, and motives for organic yoghurt purchase. An online survey was conducted among organic yoghurt buyers. More than a third of respondents buy and consume organic yoghurt two to three times a month. Respondents buy most often organic yoghurt made from cow’s milk, in plastic packaging, in supermarkets and specialty stores. The most important motives for buying organic yoghurt are health, nutritional value, and food safety. Respondents have positive attitudes about organic yoghurt. The results of this research are useful for organic food producers (especially organic yoghurt producers) in planning and improving production, and also for food marketing experts in designing and implementing promotional activities.

Correlation between milk composition and selected blood indicators of liver function in ewes during lactation

The objective of this study was to research correlations between milk composition and selected blood indicators of liver function in ewes during lactation. The research was conducted with samples of milk and blood from Travnik Pramenka ewes (n = 99). Samples were collected in the area of western Slavonia in Croatia from lactating sheep grazing on natural pastures. Chemical composition of sheep milk was analysed as well as biochemical parameters in serum. Positive correlation between ALB : TGC, ALB : ALT, GUK : GGT, CHOL : ALT and AST : GGT was determined, while significant negative correlation was determined between GUK : ALB, GUK : TGC, GUK : ALT, ALB : GGT as well as ALT : GGT. Significant positive correlation was determined between blood and milk indicators, like ALB protein (r = 0.243), ALB : DMNF (r = 0.309) and ALB : SCC (r = 0.249), as well as negative correlation between TGC : MY (r = -0.264), ALT : protein (r = -0.258), lactose : TGC (r = -0.274) and ALT : DMNF (r = -0.234). The relations between indicators of milk composition, milk production and ewes blood indicators as well as their mutual connections indicate the justification of using the analysis of liver status indicators. Accordingly, by using these relations metabolic pathways of liver status indicators could be better monitored, which is important for practice regarding prevention of possible feeding errors and prevention of major production losses while maintaining the health of lactating sheep.

Caseinolytic proteases of Lactobacillus and Lactococcus strains isolated from fermented dairy products

Proteases of Lactobacillus and Lactococcus strains catalyze casein degradation in fermented dairy products, which can result in the production of bioactive peptides. Proteolytic properties of a selection of lactic acid bacteria (LAB) strains previously isolated in Croatia, including Lactococcus lactis and Lactobacillus strains, are described. All strains of Lactobacillus and Lactococcus showed an Fmc+ phenotype that can be associated with efficient growth in milk. The significant caseinolytic effect, after incubation of culture supernatant or concentrated cell biomass, was observed for Levilactobacillus brevis D6 and Lactiplantilactobacillus plantarum D13 after growth in the optimal growth medium, while for Lactoccocus lactis ZGBP5-32 and Levilactobacillus brevis SF9B strains after growth in skimmed milk. To assess the LAB growth in skimmed milk, the acidification rate was monitored. Statistically, significant acidification capacity was determined for L. plantarum D13 in the optimal medium and by the proteolytic strain Lactobacillus helveticus M92 in skimmed milk. After extraction of proteinases from the strains with caseinolytic activity, protein samples were analysed by the SDS-PAGE. The protein extract of the Lc. lactis ZGBP5-32 and ZGZA7-10, retained proteolytic activity even at very low concentrations. The ultrafiltration improved protein extraction. The crude extract possibly contained putative protease, as a decrease in contaminating proteins was confirmed by SDS-PAGE in samples of L. brevis D6 and SF9B, L. fermentum D12 and L. plantarum D13.

Protein characterisation and antioxidant potential of fresh cheese obtained by kombucha inoculum

Protein profile, in vitro gastrointestinal digestion and antioxidant potential of two fresh cheese samples obtained by kombucha inoculum and traditional starter culture have been investigated in this study. There is a significant difference in protein profile and bioactive potential between fresh cheese samples. Kombucha fresh cheese contains higher proportion of protein, predominantly the casein fractions (α-casein and β-casein) compared to fresh cheese obtained by traditional culture. After gastrointestinal digestion (with pepsin and pancreatin), significantly higher amount of soluble protein and higher degree of hydrolyses were measured in kombucha fresh cheese sample than sample obtained by traditional culture. During gastrointestinal digestion, for fresh cheese with traditional starter both fractions of casein are degraded more rapidly by pepsin than in kombucha fresh cheese. The hydrolysates of cheese obtained by kombucha inoculum showed higher phenolic content and higher antiradical scavenging abilities than hydrolysates of fresh cheese produced with traditional starter. These results suggest that kombucha inoculum contributes to improvement of product’s bioactive potential.

Influence of k-casein genotype on heat stability and cheese making properties of milk powder

In this study the effect of k-casein gene polymorphism on the technological characteristics of milk powder obtained by spray (AA1:BB1) and freeze drying (AA2:BB2) was investigated. Standardized and generally accepted methods were used in the field of physical and chemical control of dairy products, as well as methods for assessing the heat stability and cheese making properties of milk. The most heat-resistant were the samples with a predominance of milk obtained from cows with the AA CSN3 genotype, in the pH range from 6.4 to 7.0 (36-91 minutes for AA1:BB1 and 37-101 minutes for AA2:BB2). In systems with a fraction of 25 % to 100 % of milk from cows with the AA CSN3 genotype obtained by freeze drying, higher (by 3-10 %) stabilization qualities of protein were revealed when heated in the pH range from 6.4 to 7.0 compared to spray drying. The analysis of the results regarding the cheese making properties showed that with an increase in the proportion of milk from cows with the BB CSN3 genotype from 0 % to 100 % in model systems, the rennet coagulation time decreases for all samples, regardless of the drying method. It was also found that when using freeze drying, coagulum of all samples were assigned to the highest class of milk quality in terms of cheese making properties, while during spray drying only the samples consisting of min. 75 % or completely of milk obtained from cows with genotype BB CSN3 corresponded to this category.

Antimicrobial resistance of Staphylococcus aureus strains isolated from cow raw milk samples from Albania and Serbia

This research aimed to determine the prevalence rate of antimicrobial resistance (AMR) of Staphylococcus aureus isolated from raw cow milk samples in Albania and Serbia. A total of 100 raw milk samples, 50 from Albania and 50 from Serbia, have been collected from randomly selected cattle farms. Twelve samples (12 %) were positive for S. aureus, five of those originating from Albania (41.66 %) and seven from Serbia (58.33 %). Resistance of isolated S. aureus strains to ampicillin in milk samples from Albania (36.7 %) and Serbia (34.1 %) was the most common. Some of S. aureus strains from milk samples from Albania were resistant to tetracycline (16.9 %), while isolates from milk samples from Serbia were more resistant towards oxacillin (18 %). The recorded resistance towards erythromycin (13.2 %; 13.1 %), and sulfatrim (7.6 %; 6.9 %) was similar between both milk samples, respectively. The obtained results have shown higher resistance of S. aureus strains towards cephalothin in milk samples from Serbia (3.9 %) compared to milk samples from Albania (1.6 %), respectively. All isolates tested for antibiotic sensitivity were susceptible to methicillin, vancomycin, chloramphenicol, and ciprofloxacin. The obtained results regarding the minimum inhibitory concentrations (MICs) of antibiotics indicated that isolates were resistant to tetracycline, oxacillin, erythromycin, and ampicillin, respectively. Results of our investigation have shown that the found antibiotics residues are related to the usage of erythromycin (72.6 % and 73.9 %), followed by ampicillin (70.4 % and 71.2 %) while residues of ciprofloxacin in the analysed milk samples was not registered.

Evaluation of microbial quality and safety of selected dairy products with special focus on toxigenic genes of Bacillus cereus

Although dairy products play a significant role in human nutrition, they may cause a risk to the consumers. This study intends to determine the microbial contamination level in selected milk products concerning Bacillus cereus enterotoxigenic genes. Three hundred plant-origin flavoured cheese, flavoured yogurt, flavoured drinking yogurt, kareish (skim milk cheese), soft cheese, and Ras (Romy) cheese (50 samples for each) were randomly collected from retail markets at different districts in El Fayoum Governorate, Egypt. The microbiological analysis and the molecular identification of Bacillus cereus by multiplex PCR were applied and revealed potential risks associated with consumption of the tested milk products (white soft, Ras, and kareish cheeses). In all analysed cheeses (white soft, Ras and kareish) a high contamination level with coagulase positive staphylococci (20.0 %, 22.0 % and 20.0 %) and coliform bacteria (76.0, 86.0, and 88.0 %) was detected. The highest percent (78.0 %) of fungi was found in kareish cheese samples. Bacillus licheniformis was the most aerobic spore forming bacteria detected in kareish cheese (23.7 %) and flavoured drinking yogurt (17.0 %) samples. The highest prevalence (8.0%) of Bacillus cereus was recorded in the flavoured drinking yogurt and white soft cheese samples. The (nhe) was the most detected gene (100.0 %) in all of the examined samples. There was a significant difference (p<0.05) between nhe and ces genes in all investigated samples except in flavoured drinking yogurt samples. Salmonella sp., Escherichia coli and Pseudomonas aeruginosa were not detected. This survey is one of the very few surveys that describe the safety and quality status of plant-origin flavoured cheeses and flavoured drinking yogurt, particularly in Egypt.