Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Cheese”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 523 records · Page 29Linked to original sources
PubMed1982

[Changes in the fats in yellow cheese treated with surface antimold agents].

Studied were the changes setting in with fats in the process of ripening of the ewe milk yellow cheese, kashkaval type, and cow milk yellow cheese Vitosha treated with the antimold preparations 'antiplessin' and 'potassium sorbate with movilit'. There were slightly expressed hydrolytic and oxidation processes involving the milk fat. On the 60th day fat acidity after Ketstorfer was 2.17 degrees K, resp., 2.25 degrees K, on an average, with ewe milk kashkaval, and 1.92 degrees K, resp., 2.03 degrees C, on an average, with Vitosha cheese. On the 60th day of ripening the peroxide number of milk fat in kashkaval was 0.1316, resp., 0.1335, on an average, and in Vitosha cheese it was within the range of 1.0298 to 0.1454, on an average. The average values of the iodine number of fats dropped up to the 60th day, however, remained within the normal value characteristic of quality fats.--32.77, resp., 32.97 for kashkaval, and 31.40, resp., 29.30 for cheese Vitosha. No epihydrin aldehyde was found in both types of cheese up to the 60th day of ripening with the use of the two preparations.

Animals↗
PubMed1982

[Use of buffalo milk as raw material in the processing of Mozzarella cheese].

The present research aimed to compare the physico-chemical, and organoleptic properties of Mozzarella cheese prepared with buffaloes' milk, cow's milk or blending of equal parts of both types. The manufactured cheeses were evaluated for their organoleptic characteristics as well as for pH value, acidity, moisture, fat, ash, protein, and soluble nitrogen contents. It was verified that buffaloes' milk alone or combined with cow's milk is feasible for preparing Mozzarella cheese, since no differences were found in taste, aroma nor texture as compared with cheeses manufactured with cow's milk alone. Cheeses from buffaloes' milk presented higher yields and higher fat content than the others. Their levels of titratable acidity, moisture, protein and soluble nitrogen were the lowest and their ash content and pH value were the highest. Chemical and physico-chemical characteristics of cheeses manufactured by blending buffaloes' and cow's milk were intermediate in relation to those made with any type of milk alone.

Animals↗
PubMedDate not supplied

Evaluation of a rapid and automated enzyme-linked fluorescent immunoassay for detecting Escherichia coli serogroup O157 in cheese.

The Vitek Immunodiagnostic Assay System (VI-DAS) for Escherichia coli O157, a rapid and fully automated test, was evaluated for use in detecting the foodborne pathogen E. coli O157:H7 in soft, semisoft, and hard cheeses. Sixty-five cheese samples were artificially contaminated at low (2-4 colonyforming units [cfu]/25 g) and high (7-10 cfu/25 g) levels with one of 2 strains of enterohemorrhagic E. coli O157:H7. Contamination at high levels was detected in all cheeses by VIDAS, whereas in 5 cheeses (7.7%) inoculated at low levels, contamination was not detected. In 15 additional cheeses inoculated with cold-stressed cells, both VIDAS and the Bacteriological Analytical Manual cultural assay detected all high and low levels of contamination. No false positives or interference from product background fluorescence was encountered in any of the cheeses tested by VIDAS.

Cheese↗
PubMed1982

Strain-Specific Synthesis of Mycophenolic Acid by Penicillium roqueforti in Blue-Veined Cheese.

Twenty of 80 strains of Penicillium roqueforti were able to produce up to 600 mg of mycophenolic acid (MPA) liter in 2% yeast extract-5% sucrose broth. Sixty-two of these strains had been isolated from the main blue-veined cheese varieties of western Europe or from starter cultures. Of these 62 dairy strains, only 7 had MPA-producing potential in vitro. These seven strains had all been isolated during the period 1975 to 1981 from the blue cheese of one individual factory. In cheese from the market, MPA (up to 5 mg kg) was only found in samples of this same factory. With MPA-producing and -nonproducing strains for the experimental manufacture of blue cheese, MPA synthesis in cheese was only detected with strains which form MPA in yeast extract-sucrose broth. The maximum MPA level at 4 mg kg was similar to that in commercial cheese. Toxicity of MPA was tested with two established human cell lines (Detroit 98 and Girardi Heart) and one established pig kidney cell line (AmII).

Journal Article↗
PubMed1994

Effect of genetically modifying the lactococcal proteolytic system on ripening and flavor development in cheddar cheese.

THREE BATCHES OF SIX CHEDDAR CHEESES WERE MANUFACTURED BY USING THE FOLLOWING LACTOCOCCAL STRAINS: (i) UC317 as a control; (ii) JL3601, a proteinase-negative derivative of UC317 transformed with high-copy-number plasmid pCI3601 containing the cloned proteinase gene complex from UC317; (iii) AM312, a proteinase-negative derivative of UC317 transformed with plasmid pMG36enpr containing the neutral proteinase gene from Bacillus subtilis; (iv) AC322, JL3601 transformed with pMG36enpr; (v) AC311, UC317 transformed with plasmid pNZ1120, which contains the aminopeptidase N (pepN) gene from Lactococcus lactis subsp. lactis MG1363; and (vi) AC321, JL3601 transformed with pNZ1120. Organoleptic and chemical analyses indicated that (i) the control cheeses, which were made with UC317, were of the highest quality; (ii) cheeses made with strains harboring pCI3601 in addition to either pMG36enpr (AC322) or pNZ1120 (AC321) did not ripen in a significantly different manner than cheeses made with AM312 (containing only pMG36enpr) or AC311 (containing only pNZ1120), respectively; (iii) cheeses made with strains that overproduce pepN did not have improved body, texture, and flavor characteristics; and (iv) cheeses made with strains harboring the neutral proteinase from B. subtilis (AM312 and AC322) underwent greatly accelerated proteolysis.

Journal Article↗
PubMed1964

OCCURRENCE OF COAGULASE-POSITIVE STAPHYLOCOCCI IN CHEDDAR CHEESE.

Samples (13) from several lots of cheddar cheese incriminated in staphylococcal food poisoning and 343 samples of cheddar cheese purchased over a 3-year period in retail markets were examined quantitatively for coagulase-positive staphylococci with the smear plate technique. Of the food-poisoning samples, 11 contained coagulase-positive staphylococci in numbers that ranged from 50 to several million per g. Of the 343 market cheese samples, 20% contained coagulase-positive staphylococci in concentrations ranging from less than 50 to more than 200,000 per g. The phage patterns of 64 of 89 cultures isolated from the food-poisoning samples placed them in the miscellaneous phage group (44A) or in phage group IV and the miscellaneous group (42D/44A); 14 had phage patterns that involved group III, the group with which food poisoning has usually been associated. In contrast, over 50% of 104 cultures from the market cheese, which were typed at 100 times the critical test dilution, had phage patterns that involved group III. Of nine selected cultures isolated from the food-poisoning cheese, three (all in phage group III) were positive for enterotoxin by intravenous injection test of cats.

Animals↗
PubMed1994

The effect of light on the vitamin B2 and the vitamin A content of cheese.

Edam type cheese was exposed to sunlight at ambient temperature and to fluorescent light at 5 degrees C. The loss of vitamin B2 (riboflavin) and vitamin A was monitored in both the surface and inner layers of the cheese and the results compared with control samples kept in the dark. The loss of riboflavin when exposed to sunlight was shown to be primarily a surface effect but losses of vitamin A were similar throughout the cheese. When exposed to fluorescent light at 5 degrees C and monitored at intervals for 10 days the loss of riboflavin was still greatest at the surface but a trend to lower values than the control was evident throughout the cheese. Vitamin A losses followed a different pattern in both sunlight and fluorescent light. There was a heavy initial loss throughout the cheese. Under fluorescent light this was followed by a period in which further loss was mainly in the surface layer. Vacuum packaging reduced the loss of riboflavin but had no effect on the loss of vitamin A.

Cheese↗
PubMed2004

Screening for peptides from fish and cheese inhibitory to prolyl endopeptidase.

Peptides from hydrolysates of fish proteins and from cheeses were analysed for inhibition of prolyl endopeptidase (PE) isolated from porcine muscle. Muscles of cod, salmon, and trout were homogenised and incubated at pH 4.0 with pepsin and then at pH 7.5 with trypsin to obtain fish protein hydrolysates. Homogenates were incubated without exogenous enzymes at pH 4.0 and 7.5 to obtain fish protein autolysates. Water-soluble extracts from "rakfisk" (a Norwegian fermented/autolysed trout muscle dish) and water-soluble extracts from Cheddar, Norvegia, Jarlsberg, and Blue cheese were also prepared. Peptides in the supernatants obtained after heat-treatment of fish hydrolysates, autolysates and water-soluble extracts of rakfisk and cheeses at 95 degrees C for 15 min were analysed for inhibition of PE. Inhibition was also measured in peptide fractions separated by reversed-phase high-performance chromatography and by gel permeation chromatography. The peptide fractions from fish hydrolysates, fish autolysates, and water-soluble extracts of cheeses inhibited PE in hydrolysing Z-Gly-Pro-amidomethylcoumarin. Inhibition by peptides from rakfisk was negligible. Pepsin + trypsin hydrolysates from the three fish species contained PE inhibitory peptides with a broad range of apparent hydrophobicity and apparent molecular mass. Autolysates from muscles of the 3 fish species contained narrow peptide peaks of different molecular mass and different apparent hydrophobicity with strong PE inhibitory activity. The content of hydrophilic inhibitory peptides was lower in cheeses than in pepsin + trypsin hydrolysates of fish muscle.

Animals↗
PubMed2006

Analysis of the volatile components of cheddar cheese by direct thermal desorption-GC x GC-TOF/MS.

Volatile compounds were isolated from Cheddar cheese using direct thermal desorption (DTD) and analysed using comprehensive 2-D GC (GC x GC) coupled with TOF MS (TOF/MS). In total 12 aldehydes, 13 acids, 13 ketones, 5 alcohols, 3 hydrocarbons and 9 miscellaneous compounds were identified at desorption temperatures of 100, 150, 200 and 250 degrees C using mature Cheddar cheese. A temperature of 150 degrees C was found to be optimum for the DTD of volatiles from mature Cheddar cheese. The major components were acetic acid, butanoic acid, 3-hydroxy-2-butanone and 2,3-butanediol. A DTD temperature of 150 degrees C was used to observe the effect of maturation (mild, medium or mature) on the volatiles of Cheddar cheese. The major components of the volatiles of mild, medium and mature Cheddar cheese were almost the same. However, their percentage compositions were found to change with the stage of maturity. DTD is simple, fast and requires only a small amount of sample (approximately 10 mg) and works well with comprehensive GC x GC-TOF/MS. Comprehensive GC also separated a number of components which remained overlapped on the single column, such as octane and hexanal.

Cheese↗
PubMed1995

The occurrence of two intracellular oligoendopeptidases in Lactococcus lactis and their significance for peptide conversion in cheese.

Two intracellular oligopeptide-preferring endopeptidases have been detected in Lactococcus lactis. A neutral thermolysin-like oligoendopeptidase (NOP) has been purified to homogeneity and an alkaline oligoendopeptidase has been partially purified. The specificity of the oligoendopeptidases towards important intermediary cheese peptides, produced by chymosin action on the caseins, clearly differs from that of the cell-envelope proteinase (CEP). NOP is active under conditions prevailing in cheese and contributes to initial proteolysis in a young cheese. It probably plays a crucial role in the degradation of an important bitter peptide in cheese, the beta-casein 193-209 fragment. The relatively low activity of the alkaline endopeptidase is further suppressed in cheese by the highly competitive actions of NOP and CEP.

Amino Acid Sequence↗
PubMed1978

[The influence of different phosphates on the flow properties of processed cheeses (author's transl)].

Processed cheese was manufactured with different types of phosphates (P1 monophosphate to P4 tetrapolyphosphate) and by various techniques. The limiting viscosity numbers of sodium casein and the casein of processed cheese were determined and the axial ratio calculated. The axial ratio of processed cheese protein was a/b=20,0 and that of sodium casein 10,0 resp. We deduce that the apparent increase of the axial ratio is caused by the depolymerization of casein caused by emulsifying salts. The flow curves of processed cheese were analysed. There is good agreement with the power law of Ostwald tau=k.Dn. Therefore processed cheeses are characterized as pseudoplasts. The influence of melting salts on the flow properties can be described by a differing emulsifying effect (P1 less than or equal P4). Temperature, concentration and salt effects are discussed for the viewpoint of correlation between aggregation-desaggregation processes and dehydration and hydration of casein.

Caseins↗
PubMed1975

[Effect of primaricin on moulds and their aflatoxin formation in cheese].

The prior condition for the application of pimaricin is its heat stability (up to 80 degrees C) and the low penetration (around 2.6 mm), so that it is available for the effect on the cheese surface for a long period. With 13 different aflatoxin forming moulds, the inhibition on the mycel development and thereby on the aflatoxin formation was tested; the different strains were inhibited to various degrees. The effect on cheese was not definite, because the native cheese surface remained free of mould for 8 weeks after pimaricin treatment, whereas cheese slices dipped into pimaricin solution were covered with moulds very soon. The aflatoxin formation itself is only inhibited, if the growth of the moulds is inhibited. Therefore the cheeses have to be treated very early before strong growth of the moulds has started. The aflatoxin formation, however only starts at a certain growth period of the moulds, but at a not completed inhibition, a reduced aflatoxin formation has to be taken into consideration.

Aflatoxins↗
PubMed1993

The levels of cadmium, nickel, manganese lead, zinc, iron, tin, copper and arsenic in the brined canned Jordanian cheese.

The levels of cadmium, nickel, manganese, lead, zinc, iron, tin, copper and arsenic in fresh sheep's milk, white brined cheese preserved in glass jars and in tin containers and their corresponding brines, salt and tin plates were determined by atomic absorption spectrophotometry. The results have been compared with those reported in recent years. Although metal levels were comparable with other investigators' data, our data shows that white brined cheese picked-up metals from tin containers and from the naturally contaminated salt, on the contrary brined cheese in preserved glass jars showed lower levels of metals. We recommend a purified salt for brine preparation and glass jars for white cheese preservation in order to minimize cheese contamination with metals from tin cans and salt.

Animals↗
PubMed1998

Identification of conjugated linoleic acid isomers in cheese by gas chromatography, silver ion high performance liquid chromatography and mass spectral reconstructed ion profiles. Comparison of chromatographic elution sequences.

Commercial cheese products were analyzed for their composition and content of conjugated linoleic acid (CLA) isomers. The total lipids were extracted from cheese using petroleum ether/diethyl ether and methylated using NaOCH3. The fatty acid methyl esters (FAME) were separated by gas chromatography (GC), using a 100-m polar capillary column, into nine minor peaks besides that of the major rumenic acid, 9c,11t-octadecadienoic acid (18:2), and were attributed to 19 CLA isomers. By using silver ion-high performance liquid chromatography (Ag+ -HPLC), CLA isomers were resolved into seven trans,trans (5-9%), three cis/trans (10-13%), and five cis,cis (<1%) peaks, totaling 15, in addition to that of the 9c,11t-18:2 (78-84%). The FAME of total cheese lipids were fractionated by semipreparative Ag+ -HPLC and converted to their 4,4-dimethyloxazoline derivatives after hydrolysis to free fatty acids. The geometrical configuration of the CLA isomers was confirmed by GC-direct deposition-Fourier transform infrared, and their double bond positions were established by GC-electron ionization mass spectrometry. Reconstructed mass spectral ion profiles of the m + 2 allylic ion and the m + 3 ion (where m is the position of the second double bond in the parent conjugated fatty acid) were used to identify the minor CLA isomers in cheese. Cheese contained 7t,9c-18:2 and the previously unreported 11t,13c-18:2 and 12c,14t-18:2, and their trans,trans and cis,cis geometric isomers. Minor amounts of 8,10-, and 10,12-18:2 were also found. The predicted elution orders of the different CLA isomers on long polar capillary GC and Ag+ -HPLC columns are also presented.

Cheese↗
PubMed1988

Influence of lactic starter inoculation, curd heating and ripening temperature on Staphylococcus aureus behaviour in Manchego cheese.

Growth and survival of Staphylococcus aureus were investigated in 52 lots of raw ewe's milk Manchego cheese manufactured and ripened under different conditions. A 5.8-fold reduction in S. aureus counts after 60 days of ripening was obtained by inoculating milk with 1% Streptococcus lactis culture, and a further 2.0-fold reduction could be achieved by adding 0.1% Lactobacillus plantarum culture. Curd heating temperature had a significant effect on S. aureus survival, with counts 4-5 times lower in cheese from 30 degrees C curd than in cheese from curd heated at 36-40 degrees C. Ripening temperature was the parameter with the greatest influence on S. aureus counts, which reached in cheese cured at 10 degrees C or 20 degrees C for 60 days levels 10 and 100 times lower, respectively, than in cheese held at 5 degrees C.

Cheese↗
PubMed1989

A survey on the microbiological quality of various cheeses in Turkey.

A survey was made at the retail level in the Erzurum, Erzincan and Van markets to study the microbial characteristics of pickled white cheese, Erzincan (Savak) Tulum cheese and Van herby cheese, the most typical cheeses of Turkey. Significant variation was found in their microbiological quality. Microbiological analysis revealed the presence of extremely high numbers of total bacteria, faecal streptococci, other microorganisms including coliforms, Staphylococcus aureus, yeast and mould, lipolytic and proteolytic microorganisms and lactic acid bacteria. A statistical relationship between the number of microorganisms and variety of cheese type was investigated.

Bacteria↗
PubMed1992

Fungi causing thread mould spoilage of vacuum packaged Cheddar cheese during maturation.

Thread mould is a defect which occurs sporadically in maturing vacuum packaged Cheddar cheese, caused by the growth of fungi in folds and wrinkles of the plastic film in which the cheese is packaged. Fungi were isolated and identified from 110 Cheddar cheese blocks exhibiting typical thread mould defects. The major causative species were found to be Cladosporium cladosporioides, Penicillium commune, C. herbarum, P. glabrum and a Phoma species. Yeasts were also frequently isolated from the cheese, the majority belonging to the genus Candida. Fungal species which can cause thread mould defects were also found in the cheese factory environment, on cheesemaking equipment, in air, and in curd and whey, providing a wide range of potential sources of contamination.

Air Microbiology↗
PubMed1994

Potential growth and control of Salmonella in Hispanic type soft cheese.

This study evaluated the growth and control of Salmonella serotypes in a soft Hispanic type cheese (Queso Fresco). Cheese was made in the laboratory using a commercial procedure and after inoculation it was stored under vacuum at temperatures ranging from 6 to 30 degrees C. The minimum temperature that allowed growth of Salmonella was 8 degrees C. Accumulated data from the growth studies were used for the development of models relating the square root of 1/LT (LT = lag time) and specific growth rate to temperature. The effect of selected antimicrobials (potassium sorbate, sodium benzoate and sodium lactate) on the growth and survival of Salmonella in milk and in cheese at various storage temperatures was also examined. Addition of sodium benzoate (0.3%) to cheese (pH 6.6) or addition of potassium sorbate (0.3%) to cheese (pH 6.0) made from milk, which was acidified to pH 5.9 with propionic acid, had a significant impact on delaying or preventing growth of the pathogen.

Acetates↗