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 37 records · Page 2Linked to original sources
PubMed1996

Characterization and extracellular activity of psychrotrophic bacteria isolated from Villalón cheese (fresh variety of Spanish sheep's milk cheese).

The incidence of psychrotrophic bacteria was investigated in a Spanish fresh ewes' cheese (Villalón). Counts of mesophiles and psychrotrophs were (log cfu/g) 5.72 +/- 1.10 and 3.90 +/- 1.01, respectively, for factory cheeses made from pasteurized-milk. Figures for hand-made cheeses made from raw-milk were 7.35 +/- 0.48 and 6.94 +/- 0.65, respectively. A total of 59 representative psychrotrophic isolates were characterized and tested for protease and lipase production at 7 and 30 degrees C. The strains were assigned to Enterobacteriaceae (predominant in raw-milk cheese), heterofermentative lactic acid bacteria (dominant in pasteurized-milk cheese and absent in raw-milk cheese) and Pseudomonas. More than 73% of the Enterobacteriaceae produced both proteolytic and lipolytic enzymes at either 30 or 7 degrees C. This percentage is considerably higher than those previously reported. The seven isolates of pseudomonads investigated produced proteases at 7 degrees C and six were positive at 30 degrees C; lipolytic activity was shown by five of the isolates at both temperatures. Among the heterofermentative lactic acid bacteria seven of the ten isolates were proteolytic at 30 degrees C.

Animals↗
PubMed1999

The cariostatic potential of cheese: cooked cheese-containing meals increase plaque calcium concentration.

OBJECTIVE: Eating cheese by itself increases plaque calcium concentration - which is probably one mechanism of the well-established action of cheese in reducing experimental caries. The objective of the present study was to determine whether consumption of cheese as part of a cooked, mixed meal (ie as it is habitually consumed) is able to increase plaque calcium concentration. DESIGN: Plaque samples were obtained from 16 adult volunteers before and 5 minutes after consumption of either a 15 g cube of cheese, one of two cheese-containing test meals, or one of two control meals. Each subject tested each of the four meals on a separate occasion. Plaque calcium concentration was measured using atomic absorption spectrophotometry. RESULTS: The test meals increased plaque calcium concentrations to a significantly greater magnitude than the control meals (P < 0.05). A non-significant trend was observed towards a larger magnitude of change in plaque calcium concentration in the 8 subjects with the lowest, compared with the 8 subjects with the highest baseline concentration. CONCLUSION: The findings suggest that cheese-containing meals increase plaque calcium concentration and thus probably protect against dental caries.

Adult↗
PubMed2000

The effect of a commercial starter culture addition on the ripening of an artisanal goat's cheese (Cameros cheese).

The evolution of physicochemical parameters, and the most important microbial groups, were determined for the following three batches of 'Cameros' goat's milk cheese during ripening: Batch R elaborated with raw milk, Batch RS elaborated with raw milk and with the addition of a starter culture, and Batch PS elaborated with pasteurized milk and with the addition of the same culture. No differences in total solids (TS) or in the content of NaCl, fat and total nitrogen (expressed as percentages of TS) were found during the ripening. The pH, fat acidity and non-protein nitrogen (NPN, expressed as a percentage of TN) showed significant differences between the batches. The inoculated batches showed the fastest drop in pH at the beginning of the ripening period, but the cheeses of Batch R showed a higher degree of lipolysis and proteolysis. The addition of a starter influenced the microbiological quality of the cheeses. Differences in the counts of Enterobacteriaceae and faecal coliforms were found between Batches R and RS after 15 days. Staphylococcus aureus increased in number during the early period of ripening and attained a population above 6 log cfu g-1 in Batch R in the period from 5 to 10 days. However, enterotoxins were not detected in this Batch. Batch R showed lower values of lactic acid bacteria at the beginning of the ripening period, but no significant differences were found between batches in the period from 5 to 15 days of ripening. At the beginning of the ripening, Lactococcus was the main lactic acid bacteria, with L. lactis lactis being predominant. After 15 days, the lactic acid bacteria counts decreased in the three batches, especially in the cheeses of Batch PS (only 2.2 log cfu g-1 was found at 60 days), as lactococci (the only lactic acid bacteria present in Batch PS) are incapable of growing under the conditions found in cheeses at the end of their ripening period. At this time, Lactobacillus was the predominant genus in Batches R and RS, with L. plantarum predominant. No lactococci were found from day 30 in Batch R and from day 40 in Batch RS. The cheeses of Batch RS received the most favourable scores from the tasting panel for all attributes judged: cut appearance, colour, aroma, taste, texture and general acceptance.

Animals↗
PubMed1997

Cadmium variations in Manchego cheese during traditional cheese-making and ripening processes.

Variations in cadmium content were determined throughout cheese manufacturing and ripening processes by applying graphite furnace atomic absorption spectrophotometry to samples of natural pasteurized milk, rennet, curd whey, pressed curd, pressing whey and cheese. The total mean cadmium contents were 4.79 +/- 2.4 and 4.67 +/- 2.1 microgram/kg fresh weight for newly-made and mature cheeses respectively. ANOVA revealed statistically significant differences (p < 0.001) in cadmium levels (fresh weight) and these differences were due to the influence of moisture content during cheese manufacture, since no statistically significant differences (p > 0.05) were found for dry weight. Nevertheless, cadmium levels based on dry weight increased during pasteurization and more noticeably on ferment addition. ANOVA performed during the ripening process revealed significant differences between portions and ripening times for both fresh and dry weights. By Tukey's test (p < 0.05) for portions, two homogeneous groups were established, one corresponding to the outer portion with a greater cadmium content and the other comprising the middle and inner portions. The contribution of cadmium to Spanish mean intake is between 0.098 and 0.147 micrograms/week for new cheese and between 0.168 and 0.245 micrograms/week for mature cheese.

Cadmium↗
PubMed1988

Effects of cheese, breadcrumbs, and a breadcrumb and cheese mixture on microhardness of bovine dental enamel in intraoral experiments.

In previous telemetric and animal experiments, cheese has been shown to be a food of low acidogenic and cariogenic potential. In vivo intraoral tests were carried out to confirm the low cariogenic potential of this substrate in humans and to explore the enamel-softening effects of toasted breadcrumbs and those of a mixture of breadcrumbs and cheese. The results confirmed the cariostatic nature of cheese and established a considerable enamel-softening effect of toasted breadcrumbs. A mixture of breadcrumbs and cheese failed to show a statistically significant difference to breadcrumbs despite a substantially lower mean value for the breadcrumbs and cheese mixture.

Adult↗
PubMed1998

Production of gamma-aminobutyric acid by cheese starters during cheese ripening.

Nine mixed-strain starters were examined for their abilities to produce gamma-aminobutyric acid. Six commercial starters were found to produce gamma-aminobutyric acid in a skim milk culture. The bacterium that produced gamma-aminobutyric acid was isolated from the mixed-strain starters, identified as citrate-utilizing Lactococcus lactis ssp. lactis (formerly L. lactis ssp. lactis biovar diacetylactis) and designated as strain 01-7. A cell extract showed glutamate decarboxylase activity, for which the optimum pH was 4.7. In pH-controlled cultivation, gamma-aminobutyric acid was generated at pH 5.0 but not above pH 5.5. Cheeses were prepared experimentally using strain 01-7 to determine the relationship between the pH values and the production of gamma-aminobutyric acid during cheese ripening. gamma-Aminobutyric acid increased linearly in the experimental cheeses as the pH of the cheese decreased. Based on these results, gamma-aminobutyric acid was concluded to be produced by the cheese starters during ripening.

Cheese↗
PubMedDate not supplied

Determination of moisture in cheese and cheese products.

Variables related to oven-drying samples of cheese and cheese products to determine moisture content were examined to provide more efficient and reproducible methods. Over 6500 samples of cheese were analyzed in an effort to modify the current AOAC procedure. The gravity atmospheric oven was unsuitable for use in accurate moisture analysis because of wide temperature differentials within the oven cavity. Use of this for oven moisture determination resulted in higher variance, which corresponded to the high temperature variation within the oven. Cheese sample preparation using an Oster blender yielded consistently lower variance in final moisture content than did preparation of cheese samples with a hand grater, rotary grater, and plug and plunger. Sample size of 3 +/- 0.25 g maximized surface area-to-volume ratios and yielded a lower error in final moisture content because of better control of ambient weight loss rates. Use of combination of disposable 5.5 cm diameter aluminum sample pans with 5.5 cm diameter glass fiber filter pads for covers produced a smaller standard deviation for moisture analysis than did the AOAC pan and insert cover and filter paper covers. All pans must be pre-dried for at least 3 h at 100 degrees C, and the glass fiber covers should be pre-dried for 1 h under the same conditions. All dried pans and covers must be stored in a desiccator with active desiccant. Equipment upgrades from the existing AOAC standard methods provide safer more efficient methods of analysis.

Algorithms↗
PubMed1999

Allergy to goat and sheep cheese with good tolerance to cow cheese.

BACKGROUND: We report on a patient who experienced allergic reactions after eating goat cheese and after touching goat and sheep cheese, but not after consuming cow's milk dairy products. OBJECTIVE: To assess the allergenicity and IgE-binding capacity of the caseins from the three different species. METHODS: Skin prick tests were carried out using whole milk and caseins from three different species (goat, sheep and cow), and whey fractions of cow's milk. Total serum IgE and specific IgE to cow's milk proteins were measured by CAP system and specific IgE against caseins and whole milk were determined by ELISA technique. To evaluate allergenic cross-reactivity, inhibition of the IgE ELISA activity to goat's milk and goat casein was tested for the three caseins. SDS-PAGE and immunoblotting was used to determine IgE binding bands in caseins. RESULTS: Skin tests were positive to sheep and goat's milk, sheep and goat casein, as well as to sheep and goat cheese. Total serum IgE was 66 kU/L and IgE determinations by CAP were negative. IgE ELISA against the caseins from goat and sheep was strongly positive, whereas it was negative to cow casein. ELISA inhibition assays revealed a high degree of cross-reactivity between goat casein and sheep casein. Immunoblotting showed three IgE-binding bands in goat casein at 31, 27 and 22 kDa, which may correspond to alpha-, beta- and gamma-caseins. A band at about 31 kDa was observed in sheep casein and another band at 34 kDa was recognized in cow casein. CONCLUSION: This patient developed allergy to goat and sheep cheese with good tolerance to cow's milk. We identified goat casein as the main allergen causing sensitization in this patient as demonstrated by in vivo and in vitro tests. A high degree of cross-reactivity between goat and sheep casein was observed.

Allergens↗
PubMed1993

Comparison of "Gen-Probe" DNA probe and PCR for detection of Listeria monocytogenes in naturally contaminated soft cheese and semi-soft cheese.

A comparison was made of three approaches for the detection of Listeria monocytogenes in naturally contaminated soft cheese and semi-soft cheese after enrichment. Enrichment broths were tested by plating them onto different selective agars, by "Gen Probe" DNA hybridization and by the polymerase chain reaction (PCR). Based on two-step enrichment, all three approaches showed high specificities (90% or more) in detecting L. monocytogenes. In contrast, the sensitivity of the Gen-Probe test was low (33% or less), whereas high sensitivities were obtained with selective plating and PCR (83% or more). Based on one-step enrichment, specificities again were high for selective plating and PCR assay (100%), whereas for the Gen-Probe assay the specificity was lower (88% or more). The best sensitivities were observed with selective plating (67%) and PCR (75%). In terms of sensitivity, specificity and analysis time, PCR applied to a two-step enrichment was the most powerful assay for detecting L. monocytogenes in soft and semi-soft cheese.

Cheese↗
PubMed1997

Rapid semi-quantitative fluorimetric determination of citrinin in fungal cultures isolated from cheese and cheese factories.

A new rapid semi-quantitative fluorimetric assay for citrinin production testing in mould cultures has been developed. The chemical structure of the citrinin makes it a weak native fluorophore. This fluorescence can be strongly enhanced in an acidic environment. A standard curve where the concentration of HCl needed to show the yellow fluorescence signal of different concentrations of citrinin was established, thus providing a semi-quantitative method to prove the capacity of toxin production of fungal cultures. Two Penicillium strains from the Spanish National Collection of Type Cultures, were studied for the toxin production on YES broth at 25 degrees C for 21 d. The culture was assayed daily for the presence/absence and quantification of citrinin by adding the HCl concentration set, and also quantified by RP-HPLC as a confirmation procedure. Experiments demonstrate that 5 d are necessary to show the presence of citrinin. As an illustration, a total of 48 strains of Penicillium isolated from cheese and cheese factories were analysed with the proposed method.

Cheese↗
PubMed1999

The Abuela Project: safe cheese workshops to reduce the incidence of Salmonella typhimurium from consumption of raw-milk fresh cheese.

OBJECTIVES: A multiagency intervention was implemented in Yakima County, Wash, to reduce the incidence of Salmonella serotype Typhimurium infections resulting from eating queso fresco (fresh cheese) made from raw milk, a traditional food in the Hispanic diet. METHODS: A pasteurized-milk queso fresco recipe with taste and texture acceptable to the Hispanic community was developed. Trained Hispanic volunteers conducted safe cheese workshops, which were attended by more than 225 persons. RESULTS: Workshop participants' acceptance of the new recipe was excellent and positive behavior changes were maintained over 6 months. CONCLUSIONS: Educational interventions in Hispanic communities can reduce the incidence of Salmonella Typhimurium associated with eating queso fresco.

Adolescent↗
PubMedDate not supplied

Determination of natamycin in cheese and cheese rind: interlaboratory collaborative study.

A collaborative test on the determination of natamycin in cheese and cheese rind was conducted. Participants were from 37 laboratories in 13 countries. Eight samples, consisting of 4 duplicates, were investigated by a spectrometric method and a liquid chromatographic (LC) method. The spectrometric method gave good results (coefficient of variation [CV] = 12%) and the LC method with ultraviolet detection gave reasonable results (CV = 25%) for levels down to 15 mg/kg (0.9 mg/dm2). For very low levels, a preconcentration step is necessary, but even then quantitation is poor (CV = 35-37%) for both methods at 1.7 mg/kg, although the presence of natamycin can be detected qualitatively. For a level of 0.3 mg/kg, quantitation is poor (CV = 39%) for the LC method and impossible (CV = 60%) for the spectrometric method.

Cheese↗
PubMedDate not supplied

Rapid spectrophotometric method for analyzing natamycin in cheese and cheese rind.

A rapid spectrophotometric method for determining natamycin in cheese and cheese rind has been developed. Samples are homogenized with acidified aqueous acetonitrile and homogenates are filtered. Natamycin is directly quantitated in filtered extracts on the basis of the characteristic third-derivative trough at 322.6 nm. Additional cleanup of extracts is not required because derivative transformation of the conventional analytical band at around 319 nm eliminates spectral interferences from other compounds. The analysis is simple and can be completed in 6 min. The equipment is easily accessible because most modern spectrophotometers allow instant generation of derivative spectra. The method needs small amounts of solvents and has good analytical characteristics. Overall recovery was 98.4 +/- 0.7%, and linearity was excellent (r = 0.9998) in the range examined (0.5-20 mg/kg). Quantitation and detection-limits were estimated at 0.5 and 0.25 mg/kg, respectively. Precision statistics based on within-day and between-days variations suggest an overall relative standard deviation of 1.4%.

Anti-Bacterial Agents↗
PubMed1994

[Cheese-packers' disease--respiratory complaints at a cheese-packing dairy].

Twenty-one present and three former employees working in the paching room of a cheese-making dairy underwent clinical examinations including symptom history, smoking habits, chest examination, and pulmonary function tests. Blood samples were drawn to determine level of peripheral eosinophil count and antibodies to microorganisms detected by air samples. Air sample concentrations of Penicillium camemberti var. candidum, used in the cheese-production, were very high (> 6000 colony forming units per cubic metre of air). In 15 of the 24 exposed workers, precipitating antibodies towards this fungus were detected, but no antibodies were detected in a reference consisting of pooled blood from 1000 donors. Of the sixteen workers with airway symptoms five had asthma requiring treatment. Two-thirds of the symptomatic cheeseworkers but only half of those without symptoms had precipitating antibodies. The high frequency of precipitating antibodies together with the clinical causes of the airway symptoms indicates an aetiological relationship between airway symptoms and heavy exposure to Penicillium camemberti.

Air Microbiology↗
PubMedDate not supplied

[Antigenic analysis of cheese mites with view to a study of cheese-makers' illness (author's transl)].

"Somatic" and "metabolic" antigens prepared from A. farinae and T. casei mites in Auvergne cheese were used for experimental immunisation: the hyper-immune serums obtained permitted 11 to 21 precipitant systems to be distinguished. An enzymatic activity could be identified on certain arcs. Research into antigenic communities showed the existence of 1 to 3 arcs common to the mite antigens, but none with the antigens obtained from the Penicillium cyclopium and Mucor fuscus moulds accompanying the mites. The results obtained thus facilitate an epidemiological investigation among the cheesemakers.

Antigens↗