Rind Of Cheese Research Articles

Virulent Phages Isolated from a Smear-Ripened Cheese Are Also Detected in Reservoirs of the Cheese Factory.

Smear-ripened cheeses host complex microbial communities that play a crucial role in the ripening process. Although bacteriophages have been frequently isolated from dairy products, their diversity and ecological role in such this type of cheese remain underexplored. In order to fill this gap, the main objective of this study was to isolate and characterize bacteriophages from the rind of a smear-ripened cheese. Thus, viral particles extracted from the cheese rind were tested through a spot assay against a collection of bacteria isolated from the same cheese and identified by sequencing the full-length small subunit ribosomal RNA gene. In total, five virulent bacteriophages infecting Brevibacterium aurantiacum, Glutamicibacter arilaitensis, Leuconostoc falkenbergense and Psychrobacter aquimaris species were obtained. All exhibit a narrow host range, being only able to infect a few cheese-rind isolates within the same species. The complete genome of each phage was sequenced using both Nanopore and Illumina technologies, assembled and annotated. A sequence comparison with known phages revealed that four of them may represent at least new genera. The distribution of the five virulent phages into the dairy-plant environment was also investigated by PCR, and three potential reservoirs were identified. This work provides new knowledge on the cheese rind viral community and an overview of the distribution of phages within a cheese factory.

Crystallization and demineralization phenomena in stabilized white mold cheese.

Stabilized white mold cheese is a commercially important variant of traditional white mold cheese (sometimes called bloomy rind cheese) that has an extended shelf life compared with the traditional permutation. The objectives of this observational study were to document mineral element movements and the development of a pH gradient in stabilized white mold cheese, and to use novel crystallographic techniques to identify crystals that form in the rind of this cheese. Cheeses from 3 separate batches were collected from a commercial supplier at d 1, 4, 10, 14, and 18 of aging and analyzed in a randomized block design. Samples from the center and rind of each cheese were analyzed for calcium, magnesium, phosphorus, sodium, and moisture content. The effect of location within the cheese wheel was significant for all effects, whereas the effect of aging time was significant for all effects except sodium content. The interaction between location within the cheese and aging time was significant for all effects. Using powder x-ray diffractometry, the crystals that formed in the rind during aging were identified as brushite (CaHPO4 · 2H2O). The accumulation of mineral elements in the rind resulted in a substantial decrease in calcium, magnesium, and phosphorus in the center. After 18 d, calcium, magnesium, and phosphorus in the center had decreased by 26.4, 14.8, and 12.1%, respectively, compared with the first day of aging. The observations in the present study represent the first definitive identification of crystals in the rind of a white mold cheese. The use of novel crystallographic techniques in the present study lays the groundwork for the use of this technology in future investigations of mineral element diffusion phenomena in surface-ripened cheese.

English

Determining the levels of biogenic amines in cheese except that it has significance for determining the nutritional value and hygienic accuracy, cheese as food can be used as a parameter to evaluate the conditions of production and/or ripening of products, and particularly in the selection of bacterial cultures. The purpose of this paper was to determine the effect of the ripening process on the amount of biogenic amines in cheese. For this purpose were conducted physico-chemical analysis, determination of biogenic amines and microbiological analysis. During the process of ripening Livno cheese from three different batches was taken one cheese from prime day and 9 th , 20 th , 29 th , 50 th , 60 th and 105 th day. From each cheese two samples were taken, one from the middle and one from the cheese rind. During 105 th day of ripening Livno cheese, the presence of triptamin, s-feniletlamine, putrescine, cadaverine, histamine, tyramine, spermine and spermidine were determinated. The maximum total values of searched biogenic amines were found 105 th day, in the middle 184.13 mg/kg and 76.26 mg/kg in the rind of cheese. With an indication that the largest share of value represent histamine with 43.9 % and tyramine with 38.2 % in the middle, respectively histamine with 31.6 % and tyramine with 31.5 % in the rind of cheese. The values of putrescine and spermine were in small ranges and they are not identified in all samples. The values of histamine and tyramine are almost a third more at 105 th than 60 th day. There was a significant difference between the middle and the rind of cheese in the values of biogenic amines. Correlation between biogenic amines and microorganisms has not been determined.

Milk fatty acid composition and cheese texture and appearance from cows fed hay or different grazing systems on upland pastures

The objective of this work was to compare milk fatty acid (FA) profile and texture and appearance of Cantal cheeses obtained from cows grazing 2 different upland grasslands: a highly diversified pasture (74 species) of area 12.5 ha managed under continuous mode (C), and a weakly diversified pasture (31 species) of area 7.7 ha (an old temporary grassland) managed under rotational mode (R). A control group of cows fed a hay-based diet (indoors, I) was used. Three equivalent groups of 12 Montbéliarde cows underwent the 3 treatments from May to September 2008. The cheeses were manufactured during 3 consecutive days in early June, early July, and late August (27 cheeses in all). The texture, appearance, and chemical composition of the cheeses were determined after 12 wk of ripening. Concentrations of total saturated FA and monounsaturated FA were higher and lower, respectively, in I milks compared with pasture milks. The concentrations of trans-11-C18:1 and cis-9-C18:1, and polyunsaturated FA as well as yellowness decreased during the season in C-derived milk but remained constant in R-derived milk, through a combined effect of grass development stage and the cows’ grazing selection. The I cheeses were, on average, firmer, less creamy, less elastic, and less yellow than the pasture cheeses. Decreasing and increasing trends in texture firmness during the season were observed for C and R cheeses, respectively. The rind of the pasture-fed cow cheese had fewer, less intensely colored, and less prominent spots than did that of I cheeses. This difference was probably due to greater migration of fat to the rind during pressing because of the lower fat melting point of the pasture-fed cow cheeses, which had higher unsaturated FA content. The greater amounts of fat deposited on the rind of the pasture-fed cow cheeses may have partially inhibited the microbial activity responsible for rind appearance. Our trial underlines the importance of the effects of grazing management associated with vegetation type on milk and cheese characteristics.

Model for changes in weight and dry matter during the ripening of a smear soft cheese under controlled temperature and relative humidity

A model predicting the weight loss and the dry matter increase in the core and in the rind of a French smear soft cheese (Munster type) has been developed. Experimental data were collected from experiments carried out in an aseptic pilot scale ripening chamber under nine different combinations of temperature (8, 12 and 16 °C) and of relative humidity (85%, 93% and 99%) according to a complete experimental design. For each run 16 samples were analysed at various ripening stages. The model took into account the water loss by evaporation, the water transfer from the core to the surface and the mass loss due to the CO 2 release. The cheese weight loss was more influenced by the relative humidity than by the temperature. The model was able to account for the experimental weight loss as well as the rind and the core dry matter, with accuracy acceptable for practical use.

High-Pressure Processing of Gorgonzola Cheese: Influence on Listeria monocytogenes Inactivation and on Sensory Characteristics

The presence of Listeria monocytogenes on the rind of Gorgonzola cheese is difficult to avoid. This contamination can easily occur as a consequence of handling during ripening. The aims of this study were to determine the efficiency of high-pressure processing (HPP) for inactivation of L. monocytogenes on cheese rind and to evaluate the influence of HPP treatments on sensory characteristics. Gorgonzola cheese rinds, after removal, were inoculated (about 7.0 log CFU/g) with L. monocytogenes strains previously isolated from other Gorgonzola cheeses. The inoculated cheese rinds were processed with an HPP apparatus under conditions of pressure and time ranging from 400 to 700 MPa for 1 to 15 min. Pressures higher than 600 MPa for 10 min or 700 MPa for 5 min reduced L. monocytogenes more than 99%. A reduction higher than 99.999% was achieved pressurizing cheese rinds at 700 MPa for 15 min. Lower pressure or time treatments were less effective and varied in effectiveness with the cheese sample. Changes in sensory properties possibly induced by the HPP were evaluated on four different Gorgonzola cheeses. A panel of 18 members judged the treated and untreated cheeses in a triangle test. Only one of the four pressurized cheeses was evaluated as different from the untreated sample. HPP was effective in the reduction of L. monocytogenes on Gorgonzola cheese rinds without significantly changing its sensory properties. High-pressure technology is a useful tool to improve the safety of this type of cheese.

Evolution of the composition of a selected bitter Camembert cheese during ripening: release and migration of taste-active compounds.

The aim of this study was to add to the understanding of changes in taste that occur during the ripening of a bitter Camembert cheese by the evolution of its composition. Physicochemical analyses were performed on rind, under-rind, and center portions of a Camembert cheese selected for its intense bitterness. At each of the six steps of ripening studied organic acids, sugars, total nitrogen, soluble nitrogen, phosphotungstic acid soluble nitrogen, non-protein nitrogen, Na, K, Ca, Mg, Pi, Cl, and biogenic amines were quantified in each portion. Changes in cheese composition seemed to mainly result from the development of Penicillium camemberti on the cheese outer layer. Migration phenomena and the release of potentially taste-active compounds allowed for the evolution of saltiness, sourness, and bitterness throughout ripening to be better understood. Apart from taste-active compounds, the impact of the cheese matrix on its taste development is discussed.

Use of surface-smear bacteria for inhibition ofListeria monocytogeneson the rind of smear cheese

Surface-smear micro-organisms isolated from Taleggio cheese were screened for their ability to inhibitListeria monocytogenes. Most of the isolates showing antilisterial activity (19% of the total) consisted of coryneform bacteria, mainly belonging to theMicrobacterium lacticumspecies. The inhibitory activity was observed also after growth at 5°C and pH 6·0. After cross-inhibition tests among inhibitory strains and between these and other pigmented, non-inhibitory strains, two bacterial mixtures were assayed as surface-smear starter of Taleggio cheese. At different ripening stages (1, 20 and 40 days), the cheese surface was contaminated with 2·5×102cfu cm−2L. monocytogenes(Ohio strain) and the growth evaluated over 15 days of incubation at 5°C. Contrary to the laboratory experiments,Listeriacould not be completely inhibited on the cheese surface. With 5·5–6·0 pH range of the cheese rind, (lower than usual values), the growth of surface-smear bacteria was delayed, or even stopped. Nevertheless, a listeriostatic effect was achieved on the surface of cheese samples contaminated at the end of ripening. This seemed to confirm the essential role played by surface-smear bacteria, within the rind microflora, in controlling the development of contaminant micro-organisms, and by competitive bacteria in reducing the overall risks associated with soft cheese. The mechanisms involved in the selection and the growth of competing bacteria on the cheese surface are also discussed.

On the Sampling of Cheese for Chemical Inspection

Comparison of the two sampling methods of cheese for chemical inspections was carried out; i. e. the International Standard Method, issued by FAO under the Code of Principles of Milk and Milk Products, and the domestic tentative sampling method, Sanitary Inspection Guide, issued by the Ministry of Health and Welfare.One of the following three techniques was used in both methods for the sampling of cheeses.a) sampling by cutting a sectorb) sampling by means of a trierc) taking a complete cheese as a sampleDomestic Blue Cheese was used as a material for technique a), domestic Gouda Cheese for technique b) and imported canned Camembert Cheese for technique c). The cheeses were analyzed, after sampling, for moisture and fat contents.No difference in anlysis values was observed for technique a) between the two sampling methods; while, in case of technique b), higher moisture values and lower fat contents were obtained by the International Method, because in this method not less than 2cm of the extremity was cut off from the plug to close the hole made in the cheese. In case of technique c), differences in the analysis values are apt to appear when surface-ripened cheese was used as a material, because in the domestic tentative method it is prescribed that the rind of surface-ripened cheese had better be excluded before sampling is done.

British Food Journal Volume 50 Issue 7 1948

British Food Journal Volume 50 Issue 7 1948