Enhancement of ester formation in Camembert cheese by addition of ethanol

Ethyl esters are often detected at trace levels in Camembert cheese. This study investigated how the addition of ethanol prior to cheesemaking influenced the composition, texture and flavour profile of Camembert compared to a control cheese manufactured under identical conditions without ethanol. No statistical differences were observed in the composition, microbes or textures of the experimental and control cheeses. However, more ethyl esters and a significantly enhanced fruity flavour perception were reported for the experimental cheeses compared to the control. The addition of 400–1200 μg/g of ethanol may be applied in the production of Camembert cheese to enhance fruity flavour.     

Camembert Cheese Water Loss through Absorbent Packaging

Moisture transport through packaging material developed for “Camembert” cheese was studied. The three-layer film contained a water absorber/desorber layer. A simulated cheese surface made the packaging material swell on water sorption. After a period of initial swelling, thickness became constant and the Total Water Desorption Rate (TWDR) from food to the atmosphere was measured. Water concentration and apparent water diffusivity in the packaging material and in the “Camembert” cheese were determined. A published algorithm for predicting TWDR was adapted to this system and validated experimentaly.     

Properties of cholesterol‐reduced Camembert cheese made by crosslinked β‐cyclodextrin

The present study was designed to examine the physicochemical and sensory properties in cholesterol‐reduced Camembert cheese made by crosslinked β‐cyclodextrin (β‐CD). The composition of cholesterol‐reduced Camembert cheese was similar to the control and the cholesterol reduction reached 90.6%. No difference was found in the total amount of short‐chain free fatty acids between the cholesterol‐reduced cheese and the control at every ripening period. The release of butyric and capric acid mostly contributed to the increase of total amount of short‐chain free fatty acids in both groups. The cholesterol‐reduced cheese produced similar amounts of individual free amino acids to the control in all periods. The scores of all rheological characteristics except for springiness were continuously increased up to 2 weeks’ ripening and decreased thereafter. Mouldy characteristics in both appearance and flavour were increased dramatically through the ripening period in both cholesterol‐reduced and the control cheeses. Based on these results, no significant difference was found in most physicochemical and sensory properties between cholesterol‐reduced Camembert cheese and the control. Therefore, we may find it possible to develop cholesterol‐reduced Camembert cheese using crosslinked β‐cyclodextrin.     

Cyclobutanones as markers for irradiated samples of Brie and Camembert cheese

The feasibility of applying a chemical method based on the formation of 2-alkylcyclobutanone to samples of irradiated soft cheese (Brie and Camembert) was investigated. Significant quantities of 2-dodecylcyclobutanone (DCB) and 2-tetradecylcyclobutanone (TCB) were detected in both types of irradiated cheese and are proposed as qualitative markers. Other members of the cyclobutanone family (decyl- and tetradecenyl-) are also thought to be present but could not be substantiated due to a lack of authentic standards. These compounds were absent from the unirradiated samples. Results also show a significant linear relationship between the irradiation dose (1 to 8 kGy) and the amount of DCB and TCB detected in the cheese.     

Antimutagenic activity of Camembert cheese on the Trp-P-1-induced mutagenicity to streptomycin-dependent strain SD510 of Salmonella typhimurium TA98

Antimutagenic activity of Camembert cheese during ripening against the mutagenicity of an amino acid pyrolysate, Trp-P-1, using the streptomycin-dependent strain (SD510) of Salmonella typhimurium TA98, was studied. The starter used for the manufacture of Camembert cheese consisted of four strains of lactic acid bacteria and one strain of Penicillium candidum. The antimutagenicity of Camembert cheese was very high and increased during ripening. When 1% cheese suspension was used, the antimutagenicity was 19% at zero week, 36% at 1 week, 50% at 2 weeks, 60% at 3 weeks and 64% at 4 weeks. It was difficult to correlate between the ripening time and antimutagenicity at a higher concentration. At a lower concentration, the activity was too low to study.     

Inclusion of microalgae in the caprine diet improves nutritional profile of milk and its Camembert cheese

The experiment was carried out to investigate the effects of supplementation with microalgae (Schizochytrium sp.) on the nutritional characteristics of milk and Camembert cheese from dairy goats. The yield and composition of milk and cheese and the sensory quality of cheese were not affected by the supplementation. As the level of supplementation increased, the concentration of docosahexaenoic acid and total n-3 fatty acids increased, whereas the ratio of n-6/n-3 and total saturated fatty acids decreased in the milk and cheese. In conclusion, supplemented goats, especially goats that received 35 g/head/day produced milk and cheese with better fatty acid composition for human consumption, without affecting the production and composition.     

Behavior of Enteropathogenic Escherichia coli in Camembert Cheese Made From Ultrafiltered Milk

Skimmilk retentates from ultrafiltration (UF) were used in combination with concentrated cream (67% milk fat) to prepare a liquid precheese mixture that with the addition of rennet, lactic starter culture and a mold spore preparation of Penicillium candidum was transformed readily into Camembert cheese upon ripening. Yield increases from the retention of soluble milk protein, closer weight control tolerances for individual cheeses and reduction in rennet in comparison to the conventional Camembert process were observed. The behavior of enteropathogenic E. coli (ECC) serotypes was demonstrated in the Camembert cheese made from UF processes. Relationships were determined in UF Camembert as to microbial type and numbers used to inoculate the precheese, and as to site of survival and growth of different EEC serotypes. Differences which were observed in the physicochemical properties between conventional and UF cheesemilk mixtures predisposed the UF Camembert cheeses to greater E. coli survival and growth than in the Camembert cheeses made conventionally.     

Camembert干酪青霉Penicillium camemberti的分离鉴定

对Camembert干酪产品的专用青霉进行培养、分离与鉴定。通过对Camembert干酪上的白色青霉进行培养,观察菌落的生长状况,分离得到两株青霉,对其中一株进行分离纯化,获得纯的菌株。经形态学鉴定,菌落为毛絮状,先呈白色,后仍保留白色或变为灰绿色,背面无色;分生孢子梗粗糙,间枝和小梗的位置在同一水平面上;分生孢子链纠结;分生孢子光滑,椭圆形后变为亚球形。利用改进的SDS裂解法提取Camembert干酪青霉的基因组DNA,以rDNA保守序列引物ITS549I,TS212d,经PCR扩增出16S DNA转录间隔区目的片段(约330 bp),测序并经GenbankBlast比对,鉴定该序列与Penicillium camemberti相似性达100%。     

pH spatial distribution model during ripening of Camembert cheese

During ripening of Camembert cheese, a soft cheese, the pH values continually change, which impacts the growth of Listeria monocytogenes. In this study, a pH distribution model suitable for the ripening phase of Camembert cheese was developed and verified. An experimental trend-based statistical model for pH using normalized time and normalized pH as variables was developed to determine the evolution of pH. The pH model showed good agreement with the mean pH measured values, i.e., the pH model was able to capture the magnitudes and trends sufficiently. The R² values for top surface, center, inner-outer side surface, and bottom surface regions’ mean measured and pH model-predicted values were 0.97, 0.95, 0.99, and 0.99, respectively.     

Influence of Diafiltration, Lactose Hydrolysis and Carbon Dioxide on Enteropathogenic Escherichia coli in Camembert Cheese Made from Ultrafiltered Milk

Double diafiltration with simultaneous partial fermentation of skim-milk retentates reduced the buffering capacity of ultrafiltered retentates and suppressed the survival and growth of enteropathogenic E. coli (EEC) serotype 0124 in Camembert cheese made by ultrafiltration (UF) processes. Hydrolysis of lactose in ultrafiltered retentates did not increase starter culture activity against EEC 0124 survival and growth in UF Camembert cheese. Carbon dioxide suppressed EEC 0124 development in UF Camembert cheese along with the growth of the normal ripening microflora necessary for cheese production.     

Dynamic growth models for L. monocytogenes during ripening in Camembert cheese

Population density curves for L. monocytogenes in Camembert cheese were obtained during ripening. The pH, moisture content, and the specific growth rate values for survival and growth data for each trial were used to develop and verify three levels of accuracy Camembert cheese Dynamic Models (CDMs) (location, region, and section-specific dynamic growth models). The location-specific dynamic growth model provided the most detailed information and had highest accuracy for the prediction of L. monocytogenes during ripening of Camembert cheese. Experimental data had a good fit with calculated values for the three levels of CDMs: (1) for location-specific dynamic growth model, the R² values for top center (TC), top surface (TS), center (C), bottom center (BC), and bottom surface (BS) regions were 0.92, 0.94, 0.91, 0.94, and 0.95, respectively. The standard error ranged from 0.19 to 0.24 log(CFU/g). (2) For region-specific dynamic growth model, the R² values for two regions were 0.93 (TS and C) and 0.94 (TC, BC, and BS), respectively. The standard errors were 0.19 and 0.22 log(CFU/g), respectively. (3) For section-specific dynamic growth model, the R² value was 0.93 with standard error of 0.27 log(CFU/g).     

2‐Alkylcyclobutanones as markers for the detection of irradiated mango,papaya, Camembert cheese and salmon meat

Experimental work was carried out in order to determine the usefulness of the 2‐alkylcyclobutanones as markers for irradiated Camembert cheese, salmon meat, mango and papaya. Both 2‐dodecylcyclobutanone (2‐DCB) and 2‐tetradecylcyclobutanone (2‐TCB) were readily detected in Camembert cheese even after storage for 26 days at 10 °C. A linear relationship was observed between irradiation dose (0.5–5 kGy) and the amount of cyclobutanone produced in the cheese. 2‐DCB and 2‐TCB were both identified in salmon meat irradiated in either the chilled (4 °C) or frozen state (−40 °C), although it was noted that less 2‐DCB was measured in the frozen samples. A linear response to increasing irradiation dose was demonstrated for salmon over the experimental range of 1–10 kGy. 2‐TCB was identified as the main marker for irradiated mango and could be detected in samples following storage for 14 days at 10 °C at doses as low as 0.1 kGy. As for the other products investigated, the concentration of this cyclobutanone increased linearly with increasing dose (0.1–2 kGy). With regard to papaya, 2‐DCB was identified as the principal irradiation marker. However, the concentration of this cyclobutanone decreased significantly with time, so that by day 21 of storage at 10 °C it could only be detected at the 2 kGy dose level. 2‐Tetradecenylcyclobutanone (2‐TDCB) was also detected in irradiated mango and papaya. © 2000 Society of Chemical Industry     

The growth, properties and interactions of yeasts and bacteria associated with the maturation of Camembert and blue-veined cheeses

The growth of yeasts and bacteria were monitored during the maturation of Camembert and blue-veined cheese produced in Australia. Yeasts were prominent throughout maturation, growing to 10(5)-10(9)/g, depending on the manufacturer. Debaryomyces hansenii predominated, but there were lesser, inconsistent contributions from Yarrowia lipolytica. Of the non-lactic acid bacteria, Acinetobacter species were significant during the maturation of Camembert but not blue-veined cheeses, and grew to 10(6)-10(8) cfu/g. Staphylococcus and Micrococcus species were consistently isolated from the cheeses with Staphylococcus xylosus growing to 10(5)-10(9) cfu/g, depending on the product. Lactic acid bacteria (10(7)-10(9) cfu/g) were present throughout maturation but were not identified. Interactions between the various yeasts and bacterial isolates were examined. Several strains of D. hansenii exhibited killer activity but not against Y. lipolytica. None of the yeasts were antagonistic towards the bacteria but some strains of D. hansenii enhanced the growth of Y. lipolytica and S. xylosus. The yeast and bacterial isolates exhibited various degrees of extracellular proteolytic and lipolytic activities.     

Evaluation of Listeria innocua as a suitable indicator for replacing Listeria monocytogenes during ripening of Camembert cheese

The suitability of Listeria innocua for use as an indicator for replacing Listeria monocytogenes during the cheese-making and ripening of Camembert cheese was evaluated. Pasteurized whole milk inoculated with either L. innocua or L. monocytogenes was used to make Camembert cheese, which were ripened in three stages. All cheese was ripened in three stages: room temperature (∼20 °C) and relative humidity of 60% for 36 h; 12 °C and relative humidity of 93% for 2 weeks; and 7 °C and relative humidity of 85% for 3 weeks. Results showed that population values of L. innocua and L. monocytogenes on day 1 were 7.16 and 6.11 log₁₀ CFU/g, respectively, which declined to 6.54 and 5.45 log₁₀ CFU/g, respectively, during subsequent 20 days. Thereafter, L. innocua and L. monocytogenes populations increased to 7.38 and 6.06 log₁₀ CFU/g on day 35 of ripening, respectively. During ripening, surface and interior of cheeses were analysed for populations of L. innocua and L. monocytogenes , respectively. The data were collected on day 1, 5, 10, 15, 20, 25, 30, and 35 of ripening. Generally, the growth of L. innocua and L. monocytogenes is faster in surface than in centre. Top centre, bottom centre and bottom surface locations had similar population values during ripening. There were no significant differences ( P  > 0.05) between batch and section of cheese. The ripening time and locations had significant effect ( P  < 0.05) on the survival and growth of L. innocua and L. monocytogenes . The trends of survival and growth of L. innocua and L. monocytogenes were similar. These results indicated that L. innocua can be considered as an indicator for L. monocytogenes during ripening of Camembert cheese.     

不同成熟期Camembert干酪挥发性风味物质的分析

应用顶空固相微萃取气质联用(HS-SPME-GC-MS)对成熟期分别为15、30和45 d的Camembert干酪中的挥发性风味物质进行了分析检测.结果表明,在成熟过程中Camembert干酪产生的主要挥发性风味物质是醇、醛、酮、酯、苯环物质、烯烃类物质和挥发性有机酸.醇类物质在成熟过程中基本消失;醛类物质有增加趋势,而更多的是参与了酸类物质与酯类物质的相互转化;酮类物质大量增加,主要产生甲基酮;酸类物质含量减少或消失;酯类物质大量生成.     

Terminal-restriction fragment length polymorphism and automated ribosomal intergenic spacer analysis profiling of fungal communities in Camembert cheese

Identifying and isolating yeasts and moulds within a fungal community is challenging. The main goal of the present study was to assess a new approach for the detection and identification of fungi involved in Camembert cheese rind formation to replace the use of traditional microbiological techniques. Two molecular methods, terminal-restriction fragment length polymorphism (T-RFLP) and automated ribosomal intergenic spacer analysis (ARISA), were adapted and compared for their potential to determine fungal composition directly from cheese samples. The two techniques in combination with principal component analysis showed differences in the fungal composition of cheeses when comparing surface with centre, different batches, manufacturing processes and ripening times. Moreover, cheese stabilisation induced changes in the flora at the cheese centre, and difference in size (150 g versus 1 kg) modified surface flora. Nine fungal genera were identified in cheese samples: Cladosporium, Debaryomyces, Geotrichum, Kluyveromyces, Mucor, Penicillium, Pichia, Saccharomyces and Yarrowia.     

Camembert干酪制备酪蛋白磷酸肽的初步研究

本文以Camembert干酪流程制备的干酪为原料,分离并测定了酪蛋白磷酸肽粗制品.测得干酪中酪蛋白磷酸肽的质量分数为7.80%,利用大孔强碱性阴离子交换树脂对粗制品进行纯化,并对其阻钙沉淀活性分别进行了测定,Camembert干酪中提取的酪蛋白磷酸肽(CPPs)比商品CPPs具有更好的阻钙沉淀活性.     

Impact of preheating on the behavior of Listeria monocytogenes in a broth that mimics Camembert cheese composition

The effect of preheating on the survival of L. monocytogenes in Richard's broth, which mimics the composition of Camembert cheese composition, was examined. Experiments were carried out to reproduce contamination of cheese with environmental heat-stressed cells of L. monocytogenes surviving hot-cleaning procedures. Cells in mid-log phase were heated for 30 min at 56 degrees C before being inoculated into Richard's broth. The pHs and temperatures of Richard's broth were chosen to recreate the conditions of curd dripping (pH 5, 25 degrees C), of the beginning of cheese ripening (pH 5, 12 degrees C), and of the beginning (pH 5, 4 degrees C) and the end (pH 7, 4 degrees C) of cheese storage. Immediately after heat treatment, the viability loss was especially high for strain 306715, which exhibited only 0.6% +/- 0.2% survival, compared with 22% +/- 8.7% for strain EGD. The percentages of the surviving heated cells that were injured were 93% +/- 8% for strain 306715 and 98% +/- 3% for strain EGD. The destruction of the surviving L. monocytogenes cells was accelerated when they encountered the pH and temperature conditions of Camembert cheese during manufacturing, ripening, and cold storage (pH 5 at 25, 12, and 4 degrees C, respectively). The multiplication of the surviving heated cells was retarded under favorable growth conditions similar to those of storage by the distributor and the consumer (pH 7 at 4 and 12 degrees C, respectively).     

Determination of taste-active compounds of a bitter Camembert cheese by omission tests

The taste-active compounds of a Camembert cheese selected for its intense bitterness defect were investigated. The water-soluble fraction (WSE) was extracted with pure water and fractionated by successive tangential ultrafiltrations and nanofiltration. The physicochemical assessment of these fractions led to the construction of a model WSE which was compared by sensory evaluation to the crude water-soluble extract, using a panel of 16 trained tasters. As no significant difference was perceived, this model WSE was then used directly or mixed with other cheese components for omission tests. Among the main taste characteristics of the WSE (salty, sour, umami and bitter), bitterness was found to be due to small peptides whose mass distribution was obtained by RPHPLC-MS (400-3000 Da) and whose taste properties are discussed.     

Survival of foot-and-mouth disease virus in cheese.

Persistence of foot-and-mouth disease virus during the manufacture of Cheddar, Mozzarella, Camembert cheese prepared from milk of cows experimentally infected with the virus was studied. Cheese samples were made on a laboratory scale with commercial lactic acid starter cultures and the microbial protease MARZYME as a coagulant. Milk was heated at different temperatures for different intervals before it was made into cheese. Food-and-mouth disease virus survived the acidic conditions of Cheddar and Camembert cheese processing but not that of Mozzarella. Foot-and-mouth disease virus survived processing but not curing for 30 days in Cheddar cheese preparaed from heated milk. However, the virus survived curing for 60 days but not for 120 days in cheese (pH 5) prepared from unheated milk. Foot-and-mouth disease virus survived in Camembert cheese (pH 5) for 21 days at 2 C but not for 35 days.