Milk Cheese Samples Research Articles

Experimental Studies on the Siirt Herby Tulum Cheese: II. Evaluation of a New Industrial Process Model

This study was conducted to test a process that we had previously developed in parallel to the traditional Siirt Herby Cheese production method. Both raw and pasteurized Eve's milk were used parallelly in the study. Pasteurized milk was inoculated with an autochthonous starter culture which we have developed. After clot formation, breaking the clot, straining and acidification of curd by using acid whey, first pressing, adding herb and salt, and applying the second pressing stages were followed. Then, the cheese samples were packaged. No air gap was presented in the cheese containers. The entire production was completed within 24 hours. During the 120-d ripening period of the samples at 4 °C, pH was observed to be 5 and acidity was 0.7% (lactic acid). In raw milk cheese, pH was 6.8 and acidity was 1.12% at the end of the ripening period. It was determined that the method tested in this study was not recommendable for making raw milk cheese. The pasteurized milk cheese samples had at least 0.7 acidity, 5 pH, 20% fat and 20% protein; It was observed that at least 45% dry matter values could be obtained. However, the pasteurized milk cheese samples did not fully meet our expectations. The crumbling property of the cheese samples was not ideal just seen in the tradiditonal Tulum Cheeses of Türkiye. The slightly sticky and melted appearance was considered a negative property of the cheese and should be eliminated with more detailed work. Traditional production takes at least 10 d. This period may be long for industrial production. Raw milk is used in traditional production, and excessive salt is added to the cheese for hygiene purposes. Also, it is not easy to make a standard production. More research is needed to eliminate such negativities, and to recommend a valuable industrial process.

Seasonal variation of Salmonella enterica prevalence in milk and cottage cheese along the dairy value chain in three regions of Ethiopia

Seasonal fluctuations influence foodborne illness transmission and affect patterns of microbial contamination of food. Previous investigations on the seasonality of Salmonella enterica prevalence in dairy products in Ethiopia have been minimal. However, such data are needed to inform strategic development of effective interventions to improve food safety, as seasonal differences may affect intervention strategies. This study was conducted to identify differences in the prevalence of Salmonella in milk and cheese samples between wet and dry seasons. A longitudinal study design was utilized with a random sampling occurring during both dry and wet seasons. A total of 448 milk and cottage cheese samples were collected from Oromia, Sidama, and Amhara regions. Samples were tested for Salmonella using the ISO 6579-1: 2008 method, followed by PCR confirmation. A chi-square test was conducted to assess the significance of differences in the prevalence of Salmonella in the samples between the two seasons. Results from this study showed a higher prevalence of Salmonella in all sample types during the dry season (P < 0.05). Moreover, when comparing raw milk, pasteurized milk, and cottage cheese samples, a significant difference was observed in Salmonella prevalence from raw milk samples (27.08%) collected in the Oromia region. Additionally, data showed a significantly higher prevalence of Salmonella in samples collected from raw milk producers (29.17%) during the wet season (P < 0.05). This study indicates that in order to enhance the safety of dairy products in Ethiopia, comprehensive, long-term awareness building on hygienic milk production and handling that consider seasonal influence is warranted.

Assessment of some chemical residues in Egyptian raw milk and traditional cheese.

The assessment of risks related to food safety is becoming a challenge in developing countries with its consequent health hazards. Chemical risk assessment in dairy products is important to maintain consumer health locally and internationally. Since milk and dairy products are essential foods for a wide range of customers, mostly children, patients, and pregnant women, it is very important to estimate the risks of some chemical residues, such as pesticides, some heavy metals, and aflatoxins. This work aims to determine the levels of chemical contamination in milk and traditional Egyptian cheese. Heavy metals were determined in samples by atomic absorption spectrometry. GC-mass spectrometry (MS)/MS and LC-MS/MS were also used for measuring pesticide residues. The Aflatoxin M1 was determined by enzyme-linked immune-sorbent assay. Raw milk samples were tested and showed elevated concentrations of lead and cadmium, (46% and 4%, respectively). The heavy metals detected in the Egyptian cheese samples were variable depending on the type of cheese. Moreover, p.p.-DDE phenofose was present in 45% and 29% of raw milk and Ras cheese samples, respectively. For Aflatoxin M1, only 7% of milk samples and 2.9% of Ras cheese samples exceeded the acceptable limits. More surveying and risk assessment of chemical residues in milk and milk products are essential for controlling health risks to consumers.

Sensory Attributes and Instrumental Chemical Parameters of Commercial Spanish Cured Ewes' Milk Cheeses: Insights into Cheese Quality Figures.

The external appearance of some of the Protected Designation of Origin (PDO) cured cheeses is similar to other cheese samples made in Spain: 1 kg and 2.5-3 kg formats, cylindrical, and with or without a pleita mark on the surface. In this work, commercial cured ewe's milk cheese samples with a similar external appearance were analyzed, including five PDO and five non-PDO samples. The parameters analyzed were color, texture, pH, humidity, water activity, and the volatile profile. Additionally, a descriptive and consumer-sensory analysis of the cheese samples was carried out. Statistical analysis of the results showed that luminosity, color coordinates a* and b*, percentage of deformation, humidity, water activity, and acid contents were significantly higher in non-PDO cheese samples. The breaking force, maximum force, and the content of esters were significantly higher in those cheese samples with PDO. In addition, PDO cheese samples showed higher scores for all attributes evaluated by consumers, except for color. These results suggest that PDO cheeses are placed on the market with a higher degree of ripening than non-PDO ones and that consequently they are more positively valued by consumers.

Identification of the Enterotoxigenic Potential of Staphylococcus spp. from Raw Milk and Raw Milk Cheeses.

This study aimed to genotypic and phenotypic analyses of the enterotoxigenic potential of Staphylococcus spp. isolated from raw milk and raw milk cheeses. The presence of genes encoding staphylococcal enterotoxins (SEs), including the classical enterotoxins (sea-see), non-classical enterotoxins (seg-seu), exfoliative toxins (eta-etd) and toxic shock syndrome toxin-1 (tst-1) were investigated. Isolates positive for classical enterotoxin genes were then tested by SET-RPLA methods for toxin expression. Out of 75 Staphylococcus spp. (19 Staphylococcus aureus and 56 CoNS) isolates from raw milk (49/65.3%) and raw milk cheese samples (26/34.7%), the presence of enterotoxin genes was confirmed in 73 (97.3%) of them. Only one isolate from cheese sample (1.3%) was able to produce enterotoxin (SED). The presence of up to eight different genes encoding enterotoxins was determined simultaneously in the staphylococcal genome. The most common toxin gene combination was sek, eta present in fourteen isolates (18.7%). The tst-1 gene was present in each of the analyzed isolates from cheese samples (26/34.7%). Non-classical enterotoxins were much more frequently identified in the genome of staphylococcal isolates than classical SEs. The current research also showed that genes tagged in S. aureus were also identified in CoNS, and the total number of different genes detected in CoNS was seven times higher than in S. aureus. The obtained results indicate that, in many cases, the presence of a gene in Staphylococcus spp. is not synonymous with the ability of enterotoxins production. The differences in the number of isolates with genes encoding SEs and enterotoxin production may be mainly due to the limit of detection of the toxin production method used. This indicates the need to use high specificity and sensitivity methods for detecting enterotoxin in future studies.

Seasonal Comparison of Microbial Hygiene Indicators in Raw and Pasteurized Milk and Cottage Cheese Collected across Dairy Value Chain in Three Regions of Ethiopia.

A longitudinal design with a simple random sampling method was used to collect and compare microbial hygiene levels between the dry season (January to April) and wet season (June to August). A total of 456 milk and cottage cheese samples were collected from each site along the dairy value chain from three regions. Enumeration of total aerobic mesophilic bacteria (APC), total coliforms (TCC), and Escherichia coli (EC) was performed according to standard methods. Independent t-tests were employed to assess the significant variation at (p < 0.05) between the two seasons. The cumulative result of APC of 7.61 log cfu/mL and g and TCC of 3.50 log cfu/mL in the dry season were significantly higher than the wet season of 7.15 log cfu/mL and 2.49 log cfu/mL, respectively, whereas generic E. coli count (EC) was significantly higher in the wet season (0.70 log cfu/mL and g) than that in the dry season (0.40 log cfu/mL and g). The results of hygienic indicator microbial load significantly varied with season. Hence, hygienic milk production and handling practices that comprehend seasonal influence should be implemented to improve the safety of milk.

Use of Cyanobacterium Spirulina (Arthrospira platensis) in Buffalo Feeding: Effect on Mozzarella Cheese Quality.

The high demand for PDO buffalo mozzarella cheese is leading to the use of new strategies for feeding supplementation. Spirulina is acknowledged as a valuable source of protein with antioxidant and immune-modulatory effects in humans and animals. This investigation aimed to examine the effect of Spirulina integration in buffalo diets on mozzarella cheese quality, sensory profile, consumer acceptability, and willingness to pay (WTP). The trial was carried out on two groups of 12 buffaloes that differed in Spirulina integration: 50 g/head/d before calving (1 month) and 100 g/head/d after calving (2 months). Both the bulk milk and mozzarella cheese samples from the two groups did not differ in chemical composition. However, Spirulina inclusion influenced the sensory quality of mozzarella cheese, which resulted it being externally brighter, with a higher butter odour and whey flavour and greater sweetness, bitterness, juiciness, tenderness, oiliness, and buttermilk release than the control. The consumer test showed that information about Spirulina affected consumer liking, causing them to be in favour of the Spirulina group, leading to a higher price for it. In conclusion, Spirulina inclusion in buffalo diets affected the sensory quality of mozzarella cheese. The provision of product information to consumers can be a crucial factor in determining their liking and WTP.

Detection and characterization of the most common foodborne pathogens by using multiplex PCR procedure

Food Microbial contamination is one of the most serious problems. A large percentage of food-borne illnesses are caused by food-borne pathogens, and diarrheal agents comprise more than half of the overall prevalence of food-borne illnesses in the globe, and more commonly in developing countries. This study aimed to identify the most-common foodborne organisms from foods in Khartoum state by PCR.A total of 207 food samples (raw milk, fresh cheese, yogurt, fish, sausage, mortadella, and eggs) were collected. DNA was extracted from food samples by guanidine chloride protocol, and then species-specific primers were used to identify Escherichia coli O157: H7, Listeria monocytogenes, Salmonella spp., Vibrio cholerae, V. parahaemolyticus, and Staphylococcus aureus. Out of 207 samples, five (2.41%) were positive for L. monocytogenes, one (0.48%) was positive for S. aureus, and one (0.48%) was positive for both Vibrio cholerae and Vibrio parahaemolyticus. From 91 fresh cheese samples, 2 (2.19%) were positive for L. monocytogenes, and one (1.1%) sample was positive for two different foodborne pathogens (V. cholerae and V. parahaemolyticus). Out of 43 Cow's milk samples, three (7%) samples were positive for L. monocytogenes, and out of 4 sausage samples, one (25 %) was positive for S. aureus. Our study revealed the presence of L. monocytogenes and V. cholera in raw milk and fresh cheese samples. Their presence is considered a potential problem and needs intensive hygiene efforts and standard safety measures before, during, and after food processing operations.

Ammi-visnaga extract; a novel phyto-antiviral agent against bovine rotavirus.

The spread of bovine rotavirus has a great impact on animal productivity, milk products, and human public health. Thus, this study aimed to develop a novel, effective and accessible Phyto-antiviral treatment made from methanolic Ammi-visnaga seed extract against rotavirus infection. Rotaviruses were isolated from raw milk and cottage cheese samples randomly collected from Cairo and Qalubia governorates. They were all identified serologically, however, only three of them were both biologically and molecularly confirmed. The methanolic extract derived from Khella seeds (MKSE) was chemically analyzed with mass chromatography. The cellular toxicity of MKSE was tested on Caco-2 cells and its antiviral activity against one of the isolated bovine rotaviruses (BRVM1) was tested by both the cytopathic inhibition assay and the plaque reduction assay. Our results showed that 17.3% of the total collected 150 dairy samples were bovine rotavirus antigen positive. Three representatives of them were phylogenetically identified to be included in group A based on a 379bp coat protein gene. Visnagin, Benzopyran, Khellin, and Benzenepropanoic acid were the major active components found in the MKSE. The maximum non-toxic concentration of MKSE was 5µg/mL and the CC50 value was 417µg/mL. The MKSE exhibited in-vitro antiviral activity against BRVM1 indicated by inhibition of the viral cytopathic effect (SI = 204.5, IP = 98%), causing a 1.5 log decrease in BVRM1 TCID50 and reducing the viral plaques count by the percentage of 93.14% at MNTC (5 ug/ml). In conclusion, our study showed that bovine rotavirus represents a severe health problem that needs attention in Egypt, and it supports using MKSE as a potential natural anti-rotavirus agent.

Antimicrobial Effects of Selenium and Chitosan Nanoparticles on Raw Milk and Kareish Cheese

The contamination of milk and its dairy products with different microorganisms could cause public health hazards. Antibacterial nanoparticles (NPs) are a novel way to ensure that milk and milk products are safe. The present study investigated the effect of chitosan NPs (CS-NPs) and selenium NPs (Se-NPs) on some microorganisms, which consequently affect raw milk and Kareish cheese. Small-sized nanomaterials of Se-NPs and CS-NPs at the size of approximately 20 nm were used in this study. The samples were 700 ml raw milk and 700g Kareish cheese manufactured from 3000 mg milk. The concentrations of used nanoparticles were 0.5%, 1%, and 1.5% for Se-NPs and 2.5%, 5%, and 10% for CS-NPs. They were used to improve the microbial properties of milk and Kareish cheese samples during storage at the refrigerated temperature of 4°C. The aerobic plate count, Enterobacteriaceae count, Staphylococcus count, and mold count were significantly reduced in milk and Kareish cheese samples treated with CS-NPs and Se-NPs. The study has confirmed that CS-NPs and Se-NPs indicated high antimicrobial activity against the studied microorganisms at all concentrations although CS-NPs were more effective than Se-NPs. It can be concluded that these NPs can be used as preservatives in milk and milk products, such as Kareish cheese. In addition, increasing the concentrations of these NPs by 10% for CS-NPS and 1.5% for Se-NPS boosted their effects.

Brucella spp. Contamination in Artisanal Unpasteurized Dairy Products: An Emerging Foodborne Threat in Tunisia.

Brucellosis is a worldwide zoonotic disease transmitted to humans, predominantly by the consumption of contaminated raw milk and dairy products. This study aimed to investigate the occurrence of Brucella spp. in 200 raw milk, ricotta, and artisan fresh cheese samples, collected from individual marketing points in four districts in Tunisia. Samples were analyzed for the presence of Brucella spp. by IS711-based real-time PCR assay. Positive samples were further analyzed by qPCR for B. melitensis and B. abortus species differentiation. The DNA of Brucella spp. was detected in 75% of the samples, B. abortus was detected in 31.3%, and B. melitensis was detected in 5.3% of positive samples. A percentage of 49.3% of samples co-harbored both species, while 14% of the Brucella spp. positive samples were not identified either as B. abortus or B. melitensis. High contamination rates were found in ricotta (86.2%), cheese (69.6%), and raw milk (72.5%) samples. The study is the first in Tunisia to assess the occurrence of Brucella spp. contamination in artisanal unpasteurized dairy products and showed high contamination rates. The detection of both B. abortus and B. melitensis highlights that zoonotic high-pathogen agent control remains a challenge for food safety and consumer health protection and could represent a serious emerging foodborne disease in Tunisia.

Effect of coagulating enzymes and types of milk on the physico-chemical, proximate composition and sensory attributes of iron fortified Mozzarella cheese

Mozzarella cheese is an extremely versatile product that has been widely used by the food sector as an essential ingredient in pizza, cheeseburger, cheese-based salads, etc. The main aim of the present investigation is to study the effect of coagulating enzymes and types of milk on the physico-chemical, proximate composition and sensory attributes of iron fortified mozzarella cheese. Iron-fortified mozzarella cheese was prepared using chymosin (control group) and kiwifruit crude extract (treatment group) from three different types of milk (cow milk 100%, goat milk 100%, and cow: goat milk 50:50 ratio). SDS-PAGE of kiwifruit crude extract exhibited protein bands at 24.5 kDa, 20.3 kDa, and 18.8 kDa. The milk clotting time of kiwifruit crude extract exhibited a shorter coagulation time in the presence of CaCl2. Highly significant (p&lt;0.01) difference between enzymes, types of milk, and the interaction effect between enzymes and types of milk were noted for pH. Similarly, a highly significant difference (p&lt;0.01) was observed between types of milk and interaction effect between enzymes and types of milk while a significant difference (p&lt;0.05) was observed between enzymes for titratable acidity. The highest moisture and fat content were noted in the control group for goat and mixed milk cheese while fat, ash, and TS were comparably higher in the treatment group in mixed and goat milk cheese samples. The sensory score of mixed milk cheese enjoyed the maximum ratings by the taste panel members. Based on the findings, the present study suggests that mixed milk iron fortified mozzarella cheese (treatment group) was adjudged the best product compared to cow milk or goat milk mozzarella cheese

Detection of Enterotoxigenic Potential of Staphylococcus Aureus Isolates from Cheese Samples with Two Different Methods

Abstract The primary objective of our study was to detect the occurrence of enterotoxigenic Staphylococcus aureus in diverse types of cheese (cow’s milk cheese and mixed milk cheese) samples from R.N. Macedonia. Cheese samples were analyzed for enumeration and isolation of the S. aureus strains according to ISO 6888-1. We detected the toxigenic potential of the strains by the use of the Enzyme Link Fluorescent Assay VIDAS system, and we confirmed the presence of the SEs (sea, seb, sec, sed, see) genes by multiplex PCR. The results showed that out of 270 samples of cheese, coagulase-positive staphylococci (CPS) were detected in 27 (10%), and coagulase-negative staphylococci in five samples (1.8%). Biochemically, all 27 CPS samples were confirmed to be Staphylococcus aureus. With VIDAS SET2 test we confirmed that 11 isolates are producers of one of the toxins limited by the test. With the conventional PCR we confirmed genes in only 7 isolates. Most common detected gene was seb n=3 (42.8%), followed by sea n=2 (28.6%), and sec n=2 (28.6%). Additionally, sed and see genes were not detected in any of the S. aureus isolates. Discrepancies between the two test methods for detection of enterotoxigenic potential are not uncommon. The presence of viable Staphylococcus aureus cells that have enterotoxin potency demonstrates the importance of appropriate hygiene practices in the diary process and also the maintenance of the products in order to obtain a safe final product for the consumers.

Assessment of Aflatoxin M1 Contamination in Egyptian Milk and Cheese تقييم تلوث اللبن والجبن في السوق المصري بالأفلاتوکسين M1

A screening survey of the presence of aflatoxin M1 (AFM1) was carried out on 170 samples of Egyptian dairy products. Selected samples included raw buffalo or cow milk, pasteurized milk, UHT milk, fermented milk, soft cheese, hard cheese, and processed cheese were analyzed by competitive ELISA technique. Out of 60 liquid milk and fermented milk samples analyzed, 12 samples (20%) were found to be contaminated with AFM1, at levels ranging from 10.12 to 86.54 ng/kg. Eight from the positive samples (66.6%) failed to reach the acceptable level of the European Commission Regulation (50 ng/kg). Buffalo’s milk is safe regarding AFM1 contamination since all the buffalo milk samples were consistently negative. AFM1 was found in 22 samples (36.67%) of out 60 cheese samples at concentrations between 25.12 to 253.04 ng/kg. The highest mean value of AFM1, 231.39 ng/kg, was found in Ras cheese (hard type) samples followed by the processed cheeses with 114.76 ng/kg. Kariesh cheeses displayed the lowest levels, 53.32 ng/kg. Cheeses made from cow’s milk showed higher AFM1 positive samples, while cheeses made from buffalo’s milk tested were consistently negative. Regarding the cheese ripening age, out of 50 cow milk cheese samples, 26 were found to be positive to AFM1. The highest positive incidence was noted in long-term ripened hard cheeses (70%), while the lowest in fresh unripened cheeses (40%). It is highly recommended from the results that milk and cheese products have to be controlled periodically for AFM1 contamination.

Assessment of Viral Contamination of Five Brazilian Artisanal Cheese Produced from Raw Milk: a Randomized Survey.

Enteric viruses have been described as important contaminants in fresh and ready-to-eat foods such as sandwiches, deli meat and dairy products. This is a cross-sectional randomized survey to estimate the prevalence of norovirus and human adenovirus (HAdV) from 100 Brazilian artisanal raw milk cheese samples (Minas and Coalho) obtained from different agroindustries in four producing regions in the states of Minas Gerais and one in Piauí, respectively. From October 2017 to April 2018, norovirus genogroups I and II and HAdV were investigated in these cheese samples by RT-qPCR and qPCR, respectively. Viruses were detected in 43 samples, being 26 norovirus GI strains, 14 HAdV, and 3 both viruses. Norovirus GII strains were not detected. Viral concentrations ranged from 6.17 × 104 to 1.44 × 107 genome copies/L-1 and murine norovirus 1 used as internal process control showed 100% success rate of recovery with efficiency of 10%. There was a trend towards a higher positivity rate for both viruses in the rainy season, and HAdV were more commonly found among samples with higher fecal coliform counts. This study is a first step in assessing the risk that this contamination may pose to the consumer of raw products as well as emphasizing the need for good manufacturing practices, quality control systems in the dairy industry and markets. As a randomized survey, we established baseline figures for viruses' prevalence in five types of ready-to-eat raw milk artisanal Brazilian cheese, to allow any monitoring trends, setting control targets and future local risk analyses studies.

Antibacterial sensitivity of Escherichia coli isolated from milk and milk products in Jabalpur, MP, India

Milk and milk products are an essential element of the diet. Apart from its nutritional value, it can also serve as a carrier for multidrug-resistant bacteria attributed to many infectious diseases. The present study was conducted to detect antibiotic-resistant bacteria from milk and milk products (Raw milk, pasteurized milk, and cottage cheese) marketed in Jabalpur city of Madhya Pradesh, India. A total of 640 samples of pasteurized milk, raw milk, and cottage cheese were collected in a sterile container from different dairies and shops of Jabalpur city. Immediately after collection, samples were brought to the microbiology lab within 1 hour. The Escherichea coli were isolated from milk and cottage cheese samples, based on cultural and molecular tests. These isolates were further subjected to antibacterial susceptibility against commonly used antibiotics by the disk diffusion methods. Out of 640 samples examined, 118 (18.44%) were positive for Escherichea coli. The highest isolation of Escherichea coli was from cottage cheese (32%), followed by raw milk (22.5%) and pasteurized milk (0%). Antibiotic susceptibility profile showed that Escherichia coli were resistant for nitrofurantoin (61.8%), nalidixic acid (37.2%) and cefotaxime (30.50%). The analysis showed that 89.8 % of isolates showed multidrug resistance comprising 2-3 antimicrobials. The presence of Escherichea coli with multiple antibiotic resistances poses a significant threat to public health and food safety. These findings stress the need for better sanitation practices in the production and consumption of milk and milk products and strict monitoring of uses and misuses of antibiotics in humans and food animals.

Diversity and specificity of the bacterial community in Chinese horse milk cheese.

The nutrition and flavor of cheese are generated by the microbial community. Thus, horse milk cheese with unique nutrition and flavor, an increasingly popular local cheese of the Xinjiang Uygur Autonomous Region of China, is considered to have diverse and specific bacterial community. To verify this hypothesis, horse, cow, and goat milk cheese samples produced under the same environmental conditions and manufacturing process were collected, and the 16S rRNA gene was targeted to determine the bacterial population size and community composition by real‐time quantitative PCR and high‐throughput sequencing. The bacterial community of horse milk cheese had a significantly larger bacterial population size, greater species richness, and a more diverse composition than those of cow and goat milk cheeses. Unlike the absolute dominance of Lactococcus and Streptococcus in cow and goat milk cheeses, Lactobacillus and Streptococcus dominated the bacterial community as the starter lactic acid bacteria in horse milk cheese. Additionally, horse milk cheese also contains a higher abundance of unclassified secondary bacteria and specific secondary bacteria (e.g., Psychrobacter, Sulfurisoma, Halomonas, and Brevibacterium) than cow and goat milk cheeses. These abundant, diverse, and specific starter lactic acid bacteria and secondary bacteria may generate unique nutrition and flavor of horse milk cheese.

Chemometric analysis combined with FTIR spectroscopy of milk and Halloumi cheese samples according to species' origin.

Food adulteration is an issue of major concern, as numerous foodstuffs and beverages do not follow their labeling. Our research interest is in the field of authenticity of dairy products and particularly cheese. Adulteration of dairy products is a well‐known phenomenon, and there are numerous published studies specifically on the authenticity of cheese. In fact, substitution of a portion of fat and/or proteins, adulteration with milk of other species’ origin, and mislabeling of ingredients are some of the main issues that the science of dairy products’ authenticity is regularly facing. Discrimination of dairy products can be determined through several chemical or microbiological methods as presented in the literature. In addition, chemometric analysis is an important tool for interpretation of a huge load of measurements. The aim of this study is to discriminate between various milk samples, which is the primary ingredient of dairy products. Milk samples with different trademarks were analyzed. That data was combined with Halloumi cheese samples for chemometric discrimination of species’ origin. The innovative point of this study is the fact that it is the first time that a research study related to dairy products includes Halloumi cheese which is a traditional Cypriot cheese, not well‐studied until now. The first step of the methodology was the freeze‐drying via lyophilization of the samples. Fourier transformed infrared spectroscopy (FTIR) was chosen for their chemical characterization. Moreover, interpretation of the measurements was carried out by chemometric analysis using SIMCA software. For this study, FTIR data combined with chemometrics have given a very good discrimination of the samples according to their species’ origin. Chemometric methods such as PCA and OPLS‐DA have been used with great success. In the future, this model will be studied regarding geographical origin of the samples.

Detection of antibiotic resistance profiles and aminoglycoside-modifying enzyme (AME) genes in high-level aminoglycoside-resistant (HLAR) enterococci isolated from raw milk and traditional cheeses in Turkey.

The aim of this study was isolation and identification of the high-level aminoglycoside-resistant (HLAR) enterococci in raw milk and dairy products and to analyze their antibiotic resistance and the presence of aminoglycoside-modifying enzyme (AME) genes. A total of 59 HLAR enterococci were isolated from raw milk and traditional cheese samples. Thirty-nine of the 59 HLAR enterococci were isolated on streptomycin-containing agar medium, while the other 20 HLAR strains were isolated on gentamicin containing agar medium. The 59 HLAR enterococci were identified as 26 E. faecalis (44.07%), 18 E. faecium (30.51%), 13 E. durans (22.03%), and two E. gallinarum (3.39%) by species-specific PCR. Disk diffusion tests showed that teicoplanin were the most effective antibiotics used in this study, while 89.83% of isolates were found to be resistant to tetracycline. High rates of multiple antibiotic resistance were detected in HLAR isolates. Minimum inhibitory concentration (MIC) values of HLAR enterococci against streptomycin and gentamicin were found in the range of 64 to > 4096 µg/mL. Forty-seven (79.66%) of the 59 HLAR enterococci were found to be both high-level streptomycin-resistant (HLSR) and high-level gentamicin-resistant (HLGR) by MIC tests. However, no correlation was found between the results of the disk diffusion and MIC tests for gentamicin and streptomycin in some HLAR strains. The aph(3')-IIIa (94.92%) was found to be most prevalent AME gene followed by ant(4')-Ia (45.76%), ant(6')-Ia (20.34%) and aph(2'')-Ic (10.17%). None of the isolates contained the aac(6')-Ie-aph(2'')-Ia, aph(2'')-Ib or aph(2'')-Id genes. None of the AME-encoding genes were identified in E. durans RG20.1, E. faecalis RG22.4, or RG26.1. In conclusion, HLAR enterococci strains isolated in this study may act as reservoirs in the dissemination of antibiotic resistance genes.

Foodborne Pathogen Assessment in Raw Milk Cheeses.

General hygienic parameters and selected foodborne pathogens in raw milk cheeses at the retail level were evaluated. A total of 245 raw milk cheese samples were analysed for total bacterial count, Enterobacteriaceae, E. coli, Salmonella spp., Listeria monocytogenes, coagulase-positive Staphylococci, and staphylococcal enterotoxin. Results showed only 3 samples that were not compliant with European rules on staphylococcal enterotoxin, but coagulase-positive Staphylococci were evidenced in all samples tested. Salmonella spp. and Listeria monocytogenes were never detected whereas E. coli was evidenced in 20 samples. Results suggest a need for improvement of good manufacturing practice and milking operation.