Cheese Samples Research Articles

Molecular identification of Staphylococcus aureus-related enterotoxin genes in cheese samples.

Dairy products are considered some important sources of various nutritional compounds; however, pathogenic bacterial growth is a critical destructive factor to these products leading to consumer health and system financial crises. The current study was carried out to identify if there is any presence of Staphylococcus aureus-related enterotoxin genes in cheese samples. The research included the collection of 35 samples. The samples passed through conventional cultivation processes and a PCR method to detect the presence of icaA, sea, hla, and fnbA enterotoxin genes in these samples. The conventional identification revealed the growth of S. aureus from the cheese samples. The PCR findings recorded the presence of the icaA, sea, hla, and fnbA in 31 (88.5%), 27 (77%), 19 (54%), and 12 (34%), respectively, of cheese samples. The sequencing revealed close similarities with global isolates, which reached up to 98.5% of identity. The current results indicate the presence of enterotoxin genes of S. aureus in high rates in the dairy products examined, which reveals critical problems of food safety due to the possible presence of enterotoxins in consumer dairy products.

Molecular Characterization and Genetic diversity of Bacillus cereus isolated from karish cheese at Governorate of El-Menoufia

Food safety is an emerging global issue that impacts world trade and human health. Bacillus cereus is among the most significant global foods borne pathogens. 50 total random samples of karish cheese were obtained from a variety of food markets in Governorate of El-Menoufia. They were investigated bacteriologically in order to isolate, B. cereus species. According to the bacteriological analysis, 70% of the tested samples of karish cheese contained B. cereus species. The B. cereus isolates were resistance to Amoxicillin, Penicillin, and Amoxicillin Clavulanic acid. Contrarily, they were susceptible to Ciprofloxacin, Gentamicin, Chloramphenicol, Tetracycline and Trimethoprim Sulfamethoxazole.

Технологические аспекты создания нового вида козьего сыра

The article presents data on the study of the quality of goat’s milk, as well as goat cheese made from it. To achieve these goals, 4 samples of cheese were produced - a control and 3 prototypes with vegetable fillers in various quantities. It is shown that vegetable fillers favorably influenced the qualitative composition of cheeses.

Enhancement of weak signals by applying a suppression method to high-intense methyl and methylene signals of lipids in NMR spectroscopy.

Lipids play crucial roles in human biology, serving as energy stores, cell membranes, hormone production, and signaling molecules. Accordingly, their study under lipidomics has advanced the study of living organisms. 1-Dimensional (D) and 2D NMR methods, particularly 1D 1H and 2D 1H-1H Total Correlation Spectroscopy (TOCSY), are commonly used in lipidomics for quantification and structural identification. However, these NMR methods suffer from low sensitivity, especially in cases of low concentrated molecules such as protons attached to hydroxy, esters, aliphatic, or aromatic unsaturated carbons. Such molecules are common in complex mixtures such as dairy products and plant oils. On the other hand, lipids have highly populated fractions of methyl and methylene groups that result in intense peaks that overwhelm lower peaks and cause inhomogeneities in 2D TOCSY spectra. In this study, we applied a method of suppression to suppress these intense peaks of methyl and methylene groups to detect weaker peaks. The suppression method was investigated on samples of cheese, butter, a mixture of lipids, coconut oil, and olive oil. A significant improvement in peak sensitivity and visibility of cross-peaks was observed, leading to enhanced comparative quantification and structural identification of a greater number of lipids. Additionally, the enhanced sensitivity reduced the time required for the qualitative and comparative quantification of other lipid compounds and components. This, in turn, enables faster and more reliable structural identification and comparative quantification of a greater number of lipids. Additionally, it reduces the time required for the qualitative, and comparative quantification due to the enhancement of sensitivity.

The Pervasiveness of Bio-Hazards in Street-Vended Dairy Products

A total of 60 diverse dairy product samples, including ice cream, Ras cheese, and Kariesh cheese (20 of each), were randomly collected from street vendors in different regions of Alexandria governorate, Egypt to investigate the prevalence of pathogenic E. coli. The outcomes revealed presumptive positive colonies of 83.33% and 80% in ice cream and Kariesh cheese samples, respectively. Confirmatory tests via conventional biochemical identification affirmed the presence of E. coli in 80% of the samples. However, Vitek 2 compact testing revealed that only 46.66% were positive, in contrast to PCR techniques, which substantiated a prevalence of E. coli in only 25% of the samples, with 35% in street-vended Ras cheese and 25% in Kariesh cheese. The phoA gene, integral to E. coli, was prominently featured in street-vended Ras cheese samples at a striking 100%, while the virulence genes stx1 and stx2 were conspicuously absent, except for sporadic instances of the eaeA gene in street-vended products. These findings uncovered a nuanced landscape of bacterial presence, with E. coli exhibiting a significant prevalence disparity among product sources, particularly with street-vended items showing markedly high contamination rates. It is advised that awareness programs should be established to reduce dairy product contamination among street vendors. Keywords: Dairy; Street-vended; Escherichia coli; Contamination.

Effect of saturated and unsaturated fat on the physical properties of plant-based cheese

In many plant-based meat and dairy alternatives, coconut oil is frequently used to replicate the textural and structural properties of animal fats due to its high saturated fat content. Concerns about the health implications of saturated fat and the sustainability of coconut oil call for an exploration into alternative fat combinations in plant-based foods. The effects of saturated fatty acid (SFA) content on plant-based cheese physical characteristics were evaluated through five different ratios of coconut oil (CO) to sunflower oil (SO): 100%, 90%, 75%, 60%, 50%, 40%, 25%, 10%, and 0%. As determined through texture profile analysis, the hardness of the cheeses after setting at 5°C for 24h increased with increasing amounts of coconut oil due to the increasing solid fat content providing additional firmness. The samples with 100% coconut oil displayed satisfactory melt and stretch; however, the melt and stretch values were matched by adding as little as 25% sunflower oil. The melt and stretch values did not continue to increase with increasing saturated fat content but instead remained constant with increasing coconut oil addition. Rheological analysis of the cheeses during a temperature ramp from 20 to 95°C was assessed where the tanδ value at 95°C was used as a measure of cheese melt, where values ≥ 1 indicated a better melt. The 0% coconut oil cheese had the lowest tanδ (G″/G′) value of 0.3, whereas the addition of 25% coconut oil into the cheese resulted in the tanδ increasing to values greater than 0.5. The 25% CO cheese sample also achieved a more similar complex viscosity (η*) to that of dairy cheese than all samples but the 75% CO cheese. Therefore, there is an opportunity to decrease the amount of coconut oil in plant-based cheese systems while maintaining good functional properties and improving the sustainability and health benefits of the final product.

Fatty acid composition of Kashkaval cheese with reduced sodium chloride content

The aim of the present study was to investigate the changes in the fatty acid profile and acid value of milkfat during ripening of Kashkaval cheese with reduced sodium chloride content. Three batches of Kashkaval cheese (with low 0.7%; medium 1.5% and standard 3.1% NaCl content) were produced. Analyses were carried out on days 1 and 45 of ripening. Based on the results obtained, it was established that lipolysis in Kashkaval cheese during ripening was significantly delayed (p<0.05) in all samples. A slight increase in Kashkaval fatty acid value during ripening was established. Not statistically significant changes in the fatty acid composition of the tested samples during the 45-day ripening period were found. The average values for saturated fatty acids (SFA) were 81.08 mg/100g and for the monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA) were 11.03 and 1.04 mg/100g between control group (KSs with 3.1% NaCl content) and experimental groups (KMs with reduced NaCl content of 1.5% and KLs with a low NaCl content of 0.7 %) respectively. The predominant fatty acids (FA) were palmitic (C16, 37.56±1.13 mg/100g), myristic (C14, 16.98±0.51 mg/100g), stearic (C18, 15.35±0.46 mg/100g) and oleic acid (C18:1, 10.47±0.31 mg/100g). At the end of the ripening period, Kashkaval cheese with low content of NaCl had a slightly higher acid value of 3.03±0.58 mg KOH/g in comparison with cheese samples with medium and standard NaCl content of 1.72±0.01 and 1.11±0.01 mg KOH/g respectively.

Occurrence of Staphylococcus aureus in Different Cheese Varieties And Its Control By Thyme Oil

The present study aimed to detect the occurrence of Staphylococcus aureus in different cheese varieties in Kafr Elsheikh Governorate, Egypt, and to characterize enterotoxin virulence related genes (Sea, Seb) in the recovered Staph. aureus isolates. An additional objective was to evaluate the effectiveness of thyme oil 1% for controlling staphylococcal species in manufactured kariesh cheese with 1 and 5% salt. A total of 120 samples of different cheese samples including Damietta, kariesh, spreadable processed and Ras cheese (30 of each type) collected from different supermarkets and street-vendor at Kafr El-Sheikh governorate. The obtained results revealed the incidence of Staph. aureus wwere6.67%, 16.67%, 13.33%, and 13.33%, respectively, with overall incidence across all cheese samples was 12.5%. 23S rRNA gene was detected in staph. aureus strains isolated from damietta, kariesh, processed cheese, and Ras cheese at incidence level 6.67%, 10%, 6.67%, and 10% respectively. Seb was detected in a single Staphylococcus aureus isolate from kariesh, processed cheese, and Ras cheese, while Sea could not detect in all examined isolates. Reducing the presence of Staphylococcus aureus in kariesh cheese is crucial, as it is a favorable environment for this pathogen, which can lead to staphylococcal food poisoning. By lowering the pathogen's level in kariesh cheese, the risk to consumers can be minimized. A combination of 1% thyme oil with 1% salt demonstrated moderate inhibition against staphylococcal count, resulting in a 7.34% reduction on the 15th day of storage. Additionally, using 1% thyme oil with 5% salt resulted in a double reduction rate of 15.27% on the 15th day of storage. These findings suggest that incorporating thyme oil in the preservation of white soft kariesh cheese holds promise for enhancing its shelf life and safety.

Recent aflatoxin levels in maize, feed mixtures, milk and cheese in Serbia

Aflatoxins are the most widespread mycotoxins primar?ly produced by fungi of the genus Aspergillus such as A. flavus and A. parasiticus, infecting grains during storage, spices, nuts, milk and animal feed. Even in low concentrations, they are highly toxic. Major forms of aflatoxins include B1, B2, G1, G2, and M1. Mammals that ingest AFB1 contaminated food eliminate amounts of the main hepatic metabolite known as milk toxin or aflatoxin M1 (AFM1) via milk. The incidence of contamination of aflatoxin in maize, feed mixtures, milk and cheese samples collected from Serbian producers was investigated by using the competitive enzyme linked immunosorbent assay (ELISA) technique. In this study, a total of 22 samples of maize, 25 samples of feed mixtures, 284 samples of raw, pasteurised and UHT milk and 20 samples of cheese were examined in 2021. Aflatoxin B1 (AFB1) was quantified in 3 samples (13.6%) of maize, at levels ranging from 2.45?g/kg to 48.31?g/kg and 12 samples (48%) of feed mixtures at levels ranging from 2.04 ?g/kg to 21.48 ?g/kg. On the other hand, AFM1 was quantified in 51 samples (17.90%) of milk at levels ranging 0.02 ?g/kg to 0.26 ?g/kg and 15 samples (75%) of cheese at levels ranging from 0.15 ?g/kg to 0.46 ?g/kg. In the Republic of Serbia, maximum limit of AFB1 in maize used for livestock is 30 ?g/kg and for feed mixtures for dairy cows is 5 ?g/kg. On the other hand, maximum limit of AFM1 in milk is 0.25 ?g/kg. Maximum limit of AFM1 in cheese is not set. These results suggest the obvious presence of AFB1 in maize and the fact that number of feed mixture, milk and cheese samples contaminated with aflatoxins is not negligible. The occurence of aflatoxins in raw milk and comercially available milk is one of the most serious problems, as milk is a key source of nutrients for infants and young children. There?fore, continuous monitoring over milk is necessary as well as further research and risk analysis on AFM1 presence in cheese.

Some Physical, Chemical, Sensory Properties, Mineral Substances, and Heavy Metal Contents of Moldy Cheese Produced in Bayburt and the Surrounding Area

Moldy cheese produced in Bayburt and its surroundings is a mature cheese with a distinctive flavor that can be prepared in three ways. It is made from only Civil cheese, only cottage cheese (çökelek) or mixing the shredded Civil cheese with cottage cheese made from moderately fatty, or non-fat milk, pressing it into appropriate containers, draining the water, and allowing the cheese to organically mold. It is produced traditionally, and there are no production standards. This study was carried out to identify some of the physical, chemical, and sensory properties, mineral substances, and heavy metal contents of moldy cheeses produced and consumed in the region. In the cheese samples (24 pieces), the average dry matter (DM) rate was 51.26%, ash rate was 5.68%, salt rate was 6.21%, fat rate was 4.81%, acidity level was 0.96% and pH value was 5.79, L color value was 74.94, a color value was 0.94, b color value was 8.24. In sensory analyses, the samples scored an average of 5.94 points for color and appearance, 6.10 points in moldiness, 6.11 points for texture, 5.72 points for odor, 6.03 points for taste, 6.30 points for saltiness, and 6.01 points for general acceptability. 29 elements were examined to determine mineral substances and heavy metal concentrations. These findings are important in terms of revealing some general characteristics and heavy metal content of moldy cheese produced in the region.

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.

Microbial risk assessment of dairy products from retail marketplaces in Basrah province, Iraq.

Milk-borne bacteria cause degradation of milk products and constitute a significant risk to public health. The objectives of the present study are to determine the microbiological quality of dairy products and to investigate pathogenic microorganisms. A total of 60 samples of raw milk, homemade cheese, and yogurt were randomly selected from different retail marketplaces in Basrah. The bacteriological and biochemical tests were utilized to identify the pathogens in dairy samples, as well as the molecular technique was used as an accurate diagnostic test. The prevalence of contamination of milk products with various isolates was estimated as 50% (95% Cl: 36.8-63.2). The mean of total bacteria count for cheese was 7.29 ± 2.70, raw milk 4.62 ± 2.86, and yogurt 2.87 ± 1.05, with a significant p-value (p = 0.001). The mean count of aerobic spore-forming (ASF) contaminated raw milk was analyzed as 3.77 ± 1.18 and less contamination detected in the yogurt samples with mean of ASF was estimated as 2.52 ± 1.47 SD log 10 CFU/ml. A range of important microorganisms to human health were identified by employing the VITEK_2 system and sequencing 16S rDNA gene, including Staphylococcus aureus, Escherichia coli, Pseudomonas aerogenosa, and Bacillus cereus. The study indicates that there is a high level of bacterial contamination in dairy products with different bacteria species, which is medically important. Therefore, food safety management must be implemented to reduce biological risks carried by dairy products and ensure healthy food for consumers.

Metal-assisted core-shell plasmonic nanoparticles for small molecule biothiol analysis and enantioselective recognition.

Cysteine (Cys) enantiomorphs, important small-molecule biothiols, participate in various antioxidative, flavoring, and poison-removing processes in the food industry. Current cysteine enantiomorph analysis methods require effective strategies for distinguishing them due to their similar structures and reactivity. Herein, we present a metal ion-assisted enantiomorph-selective surface-enhanced Raman scattering (SERS) biosensor based on an amphiphilic polymer matrix (APM), which can promote cysteine enantiomorph (L/D-Cys) identification. The highly selective molecular orientation is perhaps caused by the intermolecular hydrogen bonding with chiral isomers (metal centers). The experimental results show that the SERS biosensor has a sensitivity-distincting factor toward L-Cys and D-Cys. The linear range is from 1 mmol L-1 to 1 nmol L-1, along with a low limit of detection of 0.77 pmol L-1. Moreover, the fabricated Cu-APM biosensor exhibits remarkable stability and high repeatability, with an RSD of 3.7%. Real food cysteine enantiomorph detection was performed with L-Cys-containing samples of onion, cauliflower, garlic, and apple, and D-Cys-containing samples of vinegar, black garlic, cheese, and beer. The results show that the Cu-APM biosensor can be utilized as a powerful tool for real-time determination of Cys enantiomorphs in different food samples. Thus, the metal-ion-assisted enantiomorph-selective SERS biosensor has potential as an adaptable tool for enantiomorph detection and food sample analysis.

Screening of antibiogram, virulence factors, and biofilm production of Staphylococcus aureus and the bio-control role of some probiotics as alternative antibiotics.

Food safety is a serious challenge in the face of increasing population and diminishing resources. Staphylococcus aureus is a critical foodborne pathogen characterized by its capability to secret a diverse range of heat-resistant enterotoxins. Antibiotic usage in dairy herds resulted in the occurrence of antimicrobial resistance (AMR) patterns among bacterial species, which were consequently transmitted to humans via dairy products. Lactic acid bacteria (LAB) produce bacteriocins, which provide an excellent source of natural antimicrobials with the further advantage of being environmentally friendly and safe. Detection of multidrug resistance (MDR) S. aureus isolates in concerned samples, molecular characteristics, biofilm production, and the inhibitory role of LAB against it. Random samples of raw milk and other dairy products were analyzed for S. aureus isolation. Phenotypic and genotypic assessment of AMR was performed, in addition to detection of classical enterotoxin genes of S. aureus. Finally, evaluation of the antimicrobial action of some Lactobacillus strains against S. aureus. Incidence rates of presumptive S. aureus in raw milk, Kariesh cheese, and yogurt samples were 50%, 40%, and 60%, respectively. The highest resistance of S. aureus was to Kanamycin (100%) and Nalidixic acid (89.3%), respectively. (78.66%) of S. aureus were MDR. 11.1% of S. aureus carried mecA gene. In concern with enterotoxins genes, PCR showed that examined isolates harbored sea with a percentage of (22.2%), while sed was found in (11.1%) of isolates. Regarding biofilm production, (88.88%) of S. aureus were biofilm producers. Finally, agar well diffusion showed that Lactobacillus acidophilus had the strongest antimicrobial action against S. aureus with inhibition zone diameter ranging from 18 to 22 mm. There is a widespread prevalence of MDR S. aureus in raw milk and dairy products. Production of staphylococcal enterotoxins, as well as biofilm production are responsible for public health risks. Therefore, installing proper hygienic routines and harsh food safety policies at food chain levels is substantial.

Comparison of controlling capabilities of lactobionic acid, nisin, and K-Sorbate against dairy-borne Staphylococcus aureus, Escherichia coli, and mold in soft cheese.

The utilization of chemical preservatives holds the promise of effectively controlling microbial growth in soft cheese. The first trial aimed to compare the effectiveness of lactobionic acid (LBA) and K-Sorbate in controlling the proliferation of Staphylococcus aureus, Escherichia coli, and mold in white soft cheese. The subsequent part of the study explored the inhibitory effects of K-Sorbate, nisin, and LBA on mold populations in cheese whey. Two sets of soft cheese were produced. One set was contaminated with S. aureus, while the other was with E. coli, each at concentrations of 1 log CFU/ml and 1 log CFU/100 ml. Different concentrations of LBA were incorporated into these sets of cheese. Similar cheese samples were treated with K-Sorbate. For the subsequent part of the study, it was manufactured and divided into groups that inoculated with LBA with different concentrations, K-Sorbate, and nisin. With higher S. aureus inoculation, by day 18, the positive control exhibited growth exceeding 5 log CFU/g. In contrast, the LBA treatment dropped below limit of detection (LOD) and K-Sorbate yielded 4.8 log CFU/g. While with lower S. aureus inoculation, the positive control reached log CFU/g, while LBA treatment fell below LOD by day 14, and K-Sorbate reached 2.9 log CFU/g. For E. coli inoculation, with higher concentrations, by day 18, the positive control exceeded 5 log CFU/g. Conversely, LBA treatment greatly decreased and K-Sorbate treatment measured 5.1 log CFU/g. With lower E. coli concentrations, the positive control surpassed 3 log CFU/g, yet LBA treatment dropped below LOD by day 3. Mold counts indicated some inhibition with the K-Sorbate treatment, while control groups showed growth. LBA treatments exhibit noticeable growth inhibition. About the other part of the study, the outcomes demonstrated that while growth of mold occurred in the control group, inhibitory effects were apparent in the treatment groups, and significant distinctions existed between K-Sorbate, nisin, LBA treatments, and the control group. Our findings suggest that LBA has the potential to effectively control the growth of E. coli, S. aureus, and mold in soft cheese. Moreover, LBA displays greater preservative efficacy compared to K-Sorbate and nisin.

Comparison between antibacterial effect of nanoparticles and non-nanoparticles of chitosan on Listeria monocytogenes isolated from different types of Egyptian cheese

The objectives of this paper were to investigate the existence of Listeria monocytogenes (L. monocytogenes) in different types of cheese (Mozzarella, Thalaga, and Romy cheeses, 40 samples each) sold in Assiut dairy shops and to evalute antibacterial properties of chitosan and its nanoparticles against isolated strains. L. monocytogenes was isolated in higher percentage from Mozzarella cheese (25%) followed by Thalaga and Romy cheese samples. L. monocytogenes isolates were validated by PCR utilising the 16S rRNA gene. Zeta-sizer and TEM were used to characterise nano-chitosan. The minimum inhibitory concentrations of chitosan and nano-chitosan on L. monocytogenes were detected by MIC test. Nano-chitosan (3.125%) could prevent organism growth in cheese as early as the third week. The findings revealed that 3.125% nano-chitosan had a sufficient effect on L. monocytogenes while also providing good consumer satisfaction; therefore, nano-chitosan should be utilised as a natural food additive in Egyptian dairy products.

Evaluation of the effectiveness of some essential oils against zoonotic methicillin-resistant Staphylococcus aureus isolated from dairy products and humans.

Staphylococcus aureus (S. aureus) is a zooanthroponotic, nosocomial, and community-associated pathogen that threatens livestock management and even public health. The goal of this investigation was to clarify the role of S. aureus in zoonotic illnesses. Besides that, a novel trial was conducted in the current Egyptian study using oil extracts such as cactus oil, tea oil, geranium oil, and thyme oil to demonstrate the susceptibility of methicillin-resistant S. aureus (MRSA) isolates to these organic oils in response to the alarming global concern regarding the decreased susceptibility of S. aureus to known antibiotics, which exacerbates control and treatment protocols. A total of 110 samples (45 raw cattle milk samples, 35 Karish cheese samples, and 30 human sputum samples) were collected. The bacterium was identified via traditional culturing methods, Gram staining, and the application of several biochemical tests. After that, various kinds of known commercial antibiotics were used to detect the antimicrobial susceptibility (AMS) of the obtained isolates. Furthermore, conventional polymerase chain reaction (PCR) testing was performed to identify S. aureus (nuc gene) and MRSA (mecA gene), with further application of multiplex PCR for screening of all the obtained isolates for vancomycin resistance via targeting vanA, vanB, and vanC genes. Finally, the agar gel diffusion method was performed to assess the antibacterial activity of four plant extracts (cactus oil, tea oil, geranium oil, and thyme oil) against the obtained MRSA. The culturing method revealed S. aureus positivity in raw cattle milk (13.33%), in Karish cheese (28.57%), and in human samples (20%). The obtained isolates showed mainly resistance to amoxicillin-clavulanic and ampicillin antibiotics, while the dairy samples showed further resistance against ceptaxime and an intermediate reaction against erythromycin. On the molecular side, PCR positivity was present in human samples (10%), raw cow milk (13.33%), and Karish cheese (14.29%). Nine of the fourteen PCR isolates were methicillin-resistant S. aureus (MRSA) isolates. Comparing the four oil extracts against the acquired MRSA isolates, cactus oil extract proved to be the most effective. The study's results are highly promising as they support the notion that certain essential oils possess strong antimicrobial properties against zoonotic S. aureus, thereby reducing the excessive use of antibiotics in veterinary and medical settings.

Chemometrics-driven monitoring of cheese ripening: a multimodal spectroscopic and scanning electron microscopy investigation.

The integration of spectroscopic techniques with chemometrics offers a means to monitor quality changes in dairy products throughout processing and storage. This study employed Attenuated Total Reflectance-Mid-Infrared Spectroscopy (ATR-MIR) coupled with Independent Components Analysis (ICA), and 3D Front-Face Fluorescence Spectroscopy (FFFS) paired with Common Components and Specific Weight Analysis (CCSWA). The research focused on Cheddar cheeses aged for 1, 2, 3, and 5 years, alongside Comté cheeses aged for 6, 9, and 12 months. The adopted approach offered valuable insights into the intricate cheese aging process within the food matrix. The ICA proportions and CCSWA scores highlighted the significant impact of biochemical transformations during maturation on the aging process. The extracted independent components (ICs) revealed variations in the vibration modes of amides, lipids, amino acids, and organic acids, facilitating the distinction between different cheese age categories. Additionally, CCSWA outcomes identified age-related differences through shifts in tryptophan fluorescence characteristics as the cheeses aged. These results were consistent with the observed alterations in the microstructure of cheese samples over time, corroborated by Scanning Electron Microscopy (SEM) imagery. The introduced multimodal methodology serves as a significant asset for determining the ripening stage of various types of cheese, offering a detailed perspective of cheese maturation beneficial to the dairy industry and researchers.

A study on the investigation of some properties of cheeses supplied from Kastamonu local markets

In this research, some physicochemical and microbiological analyses were performed on 10 Beyaz cheeses and 10 Lor cheeses obtained from the local markets in Kastamonu in February 2022, and it was determined whether the cheeses met the standards. Moisture, fat, fat in dry matter, protein, salt, salt in dry matter, pH, and titratable acidity values in Beyaz Cheese and Lor cheese samples were determined as 61.36-69.04%, 15.29-8.86%, 39.25-28.43%, 16.61-16.72%, 1.362-0.892%, 3.63-2.87%, 5.75-4.12, 0.150-0.172%, respectively. The average numbers of total aerobic mesophilic bacteria (TAMB), lactic acid bacteria growing on MRS agar, lactobacilli, lactic acid bacteria growing on M17 agar, lactococci, yeast-mold and coliform group bacteria in Beyaz Cheese and Lor cheese samples were determined as 7.89-7.25, 7.31-6.75, 6.93-6.84, 4.20-5.07, 5.70-0.78 log cfu/g, respectively. Based on the findings of the physicochemical analysis, it was found that the cheese samples made in the local markets of Kastamonu generally met the required standards. As a result of the microbiological analysis, coliform group bacteria were found in one of the Lor cheeses. However, coliform group bacteria were detected in all Beyaz cheese samples. These results showed that hygiene could not be ensured in the Beyaz cheese samples.

Determination of Thermotolerant Yeast Population in Dairy Products

Thermotolerant yeasts constitute a critical indicator for the effective management of product quality, food safety, and production processes in the dairy industry. This study aims to investigate the presence of thermotolerant yeasts in diverse dairy products within the context of Turkiye. In this study, pH and thermotolerant yeast properties of Turkish white cheese, butter, cream (Kaymak), and Tulum cheese were investigated. Thermotolerant yeast counts in butter samples ranged between 4.30 and 4.82 log CFU/g, with pH values ranging from 4.91 to 6.68. Thermotolerant yeast counts of Tulum cheese, white cheese and cream samples were <2 log CFU/g. The pH values of cream and Tulum cheese were ranged from pH 5.07-6.79 and pH 4.91-6.68, respectively. The mean pH value for white cheeses was 4.98. As a results, thermotolerant yeast counts of Tulum cheese, white cheese and cream samples were below the detectable value; however, a high number of thermotolerant yeasts were determined in butter samples. In conclusions, these findings offer valuable insights for evaluating the microbiological quality of different dairy products, aiding producers in enhancing safety and quality for consumers.