Effects of Penicillium roqueforti and whey cheese on gross composition,microbiology and proteolysis of mould‐ripened Civil cheese during ripening

Four different types of mould‐ripened Civil cheese were manufactured. A defined (nontoxigenic) strain of a Penicillium roqueforti (SC 509) was used as the secondary starter with and without addition of the whey cheese (Lor); in parallel, secondary starter‐free counterparts were manufactured. Chemical composition, microbiology and proteolysis were studied during the ripening. The incorporation of whey cheese in the manufacture of mould‐ripened Civil cheese altered the gross composition and adversely affected proteolysis in the cheeses. The inoculated P. roqueforti moulds appeared to grow slowly on those cheeses, and little proteolysis was evident in all cheese treatments during the first 90 days of ripening. However, sharp increases in the soluble nitrogen fractions were observed in all cheeses after 90 days. Microbiological analysis showed that the microbial counts in the cheeses were at high levels at the beginning of ripening, while their counts decreased approximately 1–2 log cfu/g towards the end of ripening.     

A survey of the chemical,biochemical, microbiological and sensorial quality of Aho cheese,a traditional cheese from Eastern Black Sea Region,Turkey

Aho cheese, a traditional Turkish dairy product, is commonly produced in the eastern Black Sea region of Anatolia. In this study, 60 samples were collected and some biochemical, microbiological and sensory qualities were investigated. The mean values for dry matter, fat, protein, salt, ash and pH were 45.04, 8.10, 26.50, 9.58, 10.64 g/100 g and 5.07, respectively. Water‐soluble nitrogen (WSN), ripening index (WSN, % of TN) and acidity index were 0.59 g/100 g, 14.50% and 4.82 mg KOH/g fat, respectively. The mean values for saturated fatty acids, monounsaturated fatty acids, polyunsaturated fatty acids and polyunsaturated fatty acid/saturated fatty acid values were found to be 73.57, 23.08, 3.38 and 0.046 g/100 g fatty acids, respectively. Total aerobic mesophilic bacteria, yeast, mould and coliform counts were between 6.20–7.44, 4.84–6.96 and 0.00–2.45 log cfu/g, respectively.     

Selected Microbiological Properties of Kashar Cheese Samples Preserved with Potassium Sorbate

Kashar cheese, traditionally produced, is a popular dairy product in Turkey. Kashar cheese—a hard cheese—is frequently contaminated with mould. Potassium sorbate can be used for preservation of Kashar cheese. In this article, the effect of potassium sorbate on the microbiological characteristics of Kashar cheese was studied. It was found that the microbial counts at stored at 4 ± 0.1°C for 12 and 24 hours were not different from that of fresh milk samples. The means of total aerobic mesophilic bacteria (TAMB), lactic acid bacteria (LAB), coliforms, Staphylococcus aureus, proteolytic microorganisms, lipolytic bacteria, psychrotrophic bacteria and yeast-moulds in the cheese samples were determined as 4.3 × 10⁷, 2.1 × 10⁵, 3.5 × 10, 1.2 × 10, 4.5 × 10⁵, 5.6 × 10⁴, 1.7 × 10³, and 4.8 × 10⁴ cfu/g, respectively. The addition of potassium sorbate to Kashar cheese decreased the coliform and yeast-mould counts. The yeast and mould counts of cheese samples with added dry potassium sorbate were lower than that of fluid potassium sorbate.     

Microbiological quality and safety of fresh cultivated and wild mushrooms commercialized in Spain

402 samples of 22 species of cultivated and wild fresh mushrooms sold in retail markets and supermarkets in Zaragoza (Spain) were studied to quantify their microbial load (mesophilic aerobic microorganisms, Pseudomonas genus, Enterobacteriaceae, lactic acid bacteria, total and thermotolerant coliform bacteria, Escherichia coli, yeasts and moulds) and to investigate the presence of E. coli O157:H7, Listeria monocytogenes, Salmonella spp., Staphylococcus aureus and Yersinia enterocolitica. The total microbial counts ranged from 4.4 to 9.4 log cfu/g, the genus Pseudomonas being the most prevalent with counts from 3.7 to 9.3 log cfu/g and Auricularia auricula-judae the species with the highest microbial load (9.4 log cfu/g). No significant differences (p > 0.05) were detected between mean counts of wild and cultivated species in all the microbial groups studied. The microbiological safety level of the cultivated mushrooms was excellent since no pathogens were isolated, and the microbial counts of indicator microorganisms were low, being detected in only half of the species. Salmonella spp, E. coli O157:H7 and S. aureus were not isolated from any sample, Y. enterocolitica was detected in only four samples of wild mushrooms whereas twenty-six (6.5%) were positive for L. monocytogenes, their occurrence being relatively high in Calocybe gambosa (40%), Hygrophorus limacinus (40%) and Tuber indicum (100%). These results suggest that a strategy to reduce bacterial populations, and to improve the microbiological safety of some species of fresh mushrooms, should be investigated.     

Microbiological attributes and biogenic amine content of probiotic Turkish fermented sausage

Microbiological attributes and biogenic amine content of Turkish fermented sausage manufactured by using probiotic starter cultures (Lactobacillus casei, L. acidophilus or their combination) were investigated before and after fermentation-drying period and during refrigerated storage at 4 ± 1 °C for 8 months at 2 month intervals. As results of the study, during fermentation and storage biogenic amine content (histamine, putrescine, cadaverine and tyramine) of the samples were increased significantly. Salmonella, Staphylococcus aureus, coliform and fecal coliform microorganisms were not detected during fermentation and storage. Probiotic microorganism counts of all samples were higher than the lower limit of 6.0 log cfu/g which is requested for probiotic foods.     

Microbiological Attributes of Turkish Butters Sold Under Market Conditions

In this study, microbiological quality of 45 butter samples sold under market conditions at Manisa (Turkey) was investigated. Total coliform, total fecal coliform, Escherichia coli and yeast and mould counts were found between < 1.0 – > 3.15 log₁₀ cfu.g^-1, < 1.0 – > 3.15 log₁₀ cfu.g^-1, < 1.0 – > 3.15 log₁₀ cfu.g^-1 and < 1.0 – > 6.62 log₁₀ cfu.g^-1 respectively. Only in one sample Salmonella was detected. Staphylococcus aureus was not detected in any of the samples. To that extent butters sold under market conditions in Manisa have high coliform, yeast and mould contamination. Received: April 29, 2008; received in revised form: May 28, 2008; accepted: June 3, 2008     

Microbiological Attributes of Turkish Butters Sold Under Market Conditions

In this study, microbiological quality of 45 butter samples sold under market conditions at Manisa (Turkey) was investigated. Total coliform, total fecal coliform, Escherichia coli and yeast and mould counts were found between < 1.0 – > 3.15 log₁₀ cfu.g^-1, < 1.0 – > 3.15 log₁₀ cfu.g^-1, < 1.0 – > 3.15 log₁₀ cfu.g^-1 and < 1.0 – > 6.62 log₁₀ cfu.g^-1 respectively. Only in one sample Salmonella was detected. Staphylococcus aureus was not detected in any of the samples. To that extent butters sold under market conditions in Manisa have high coliform, yeast and mould contamination.     

Behaviour of Listeria monocytogenes and Staphylococcus aureus in sliced,vacuum-packaged raw milk cheese stored at two different temperatures and time periods

The behaviour of Listeria monocytogenes and Staphylococcus aureus in raw milk cheese slices packaged under vacuum was evaluated. Artificially contaminated 80-day ripened cheese was portioned, vacuum packaged, and then stored for 28 days at 4 °C and for 56 days at 10 °C. Bacterial counts were obtained before vacuum packaging and then weekly during storage. At the end of ripening, the initial L. monocytogenes count was 4.46 ± 0.89 log cfu g⁻¹; weekly bacterial counts remained substantially unchanged in the samples stored at 4 °C but decreased to 3.54 ± 1.54 log cfu g⁻¹ in those stored at 10 °C. The initial S. aureus count before vacuum packaging was 3.60 ± 0.78 log cfu g⁻¹; it then gradually decreased to 2.60 ± 1.32 log cfu g⁻¹ in the samples stored at 4 °C and to about 1.9 log cfu g⁻¹ in those stored at 10 °C.     

Microbiological and Chemical Properties of Cheese Helva Produced in Turkey

In this study, the microbiological and chemical properties of Cheese helva, one of the traditional cheeses varieties produced in Turkey, was studied. This cheese is called Cheese helva since it is produced from wheat flour and milk cream. Samples were randomly collected from different villages in the Erzurum province of Turkey. The average of total aerobic mesophilic bacteria (TAMB), yeast and mould, yeast, lactic acid bacteria (LAB), proteolytic bacteria, and lipolytic bacteria were determined 4.9 × 10⁷, 6.4 × 10⁴, 3.5 × 10³, 7.6 × 10⁶, 4.6 × 10³, and 8.6 × 10³ cfu/g, respectively. 44.44% of the Cheese helva samples had no coliform; the samples that were positive for coliform showed an average of 5.1 × 10³ cfu/g. Staphylococcus aureus was found < 10 cfu/g in analyzed samples. The Cheese helva was characterized by dry matter as 84.32 kg/100 kg cheese, fat as 37.44 kg/100 kg cheese, protein as 13.75 kg/100 kg cheese, NaCI as 0.58 kg/100 kg cheese, titratable acidity as 0.210%, pH as 5.30, ash as 1.49 kg/100 kg cheese, and carbohydrate as 38.56 kg/100 kg cheese. Cheese helva was found to have a high variation based on chemical composition. The microbiological tests revealed that there were high amounts of total bacteria, yeast and molds, molds, lactic acid bacteria, lipolytic bacteria, proteolytic bacteria, and coliforms.     

Isomaltooligosaccharide increases the Lactobacillus rhamnosus viable count in Cheddar cheese

Five batches of Cheddar cheese were manufactured containing different levels of isomaltooligosaccharide (IMO) and a probiotic strain of Lactobacillus rhamnosus to study the effect of IMO on the survival of starter lactococci and probiotic micro‐organisms, on proteolytic patterns, cheese composition and sensory properties. The cheese was exposed to conditions simulating those found in the gastrointestinal tract to evaluate the survival of Lb. rhamnosus. Results demonstrated that the addition of Lb. rhamnosus and IMO did not affect the main compositional variables of Cheddar cheese. The counts of starter culture and probiotic organisms increased in cheese which contained Isomaltooligosaccharide (Batches 3, 4 and 5) more than in the control (Batches 1 and 2) during the fermentation. The probiotic counts in fresh cheese (B‐4) was 9.23 log₁₀ cfu/g which was more than one log cycle greater than in the control (B‐2). The probiotic counts remained above 8 log₁₀ cfu/g at the end of the manufacturing process. Primary proteolysis was not affected by the addition of probiotic bacteria and IMO, but the level of secondary proteolysis was slightly higher compared with the control group. The addition of IMO improved the texture and sensory quality of the cheese and the probiotic bacterium had the same effect. Under conditions that simulated the gastrointestinal tract, the probiotic bacteria in cheese (B‐4) exhibited good survival and remained above the recommended 6–7 log₁₀ cfu/g.     

Cream cheese as a symbiotic food carrier using Bifidobacterium animalis Bb‐12 and Lactobacillus acidophilus La‐5 and inulin

The stability of cream cheeses as a symbiotic food carrier, through supplementation with different concentrations of probiotic bacteria Bifidobacterium animalis Bb‐12 and Lactobacillus acidophilus La‐5 and the prebiotic ingredient inulin was investigated. Physicochemical parameters, pH values, total solids, fat and protein levels and the viable counts of the starter lactic culture Streptococcus thermophilus and probiotic cultures, were carried out at 1, 15, 30 and 45 days of refrigerated storage (8 ± 0.5 °C). Different physicochemical characteristics were observed in all formulations. S. thermophilus showed good viability in all the trials (6.66–9.38 log cfu/g), whereas B. animalis remained above 6 log cfu/g in all the trials during the period evaluated. However, L. acidophilus showed an accentuated decline, registering values of 3.1 log cfu/g at the end of the period studied. The results suggested that cream cheese was an adequate food matrix for supplementation with probiotic bacteria, in particular B. animalis, and the prebiotic ingredient, showing potential as a symbiotic food.     

Identification of staphylococci and dominant lactic acid bacteria in spontaneously fermented Swiss meat products using PCR-RFLP

Pathogenic, spoilage, and technologically important microorganisms were monitored in 21 spontaneously fermented Swiss meat products manufactured with meat from wildlife or animals grown in natural habitat. Thereby, PCR-restriction fragment length polymorphism (RFLP) on rpoB and 16S rRNA gene sequences provided a powerful tool for fast and accurate identification of the main microbial population. Lactobacillus sakei and Lactobacillus curvatus dominated in fermented meat products followed by Staphylococcus species, which constituted 88.2% of all Gram-positive, catalase-positive cocci (GCC⁺) with cell counts varying from 2.6 to 7.0 log cfu/g during maturation. Staphylococcus equorum was prevalent in frequency and cell counts during maturation (18.0%; 5.0-7.3 log cfu/g) and in the end products (28.4%; 1.8-6.2 log cfu/g) implicating a new presumptive starter species for meat fermentation. Nine out of 14 end products indicated safety risks to consumers due to the high incidence of Staphylococcus saprophyticus or Staphylococcus epidermidis combined with cell counts of 7.4 and 4.9 log cfu/g, respectively. This fact was supported by the detection of Staphylococcus aureus and Enterobacteriaceae in ready-to-eat products strongly exceeding the tolerable limit of 2 log cfu/g. Spontaneously fermented meat products produced from wildlife or animals grown in natural habitats not only gave rise to hygienic and safety concerns but also provided new presumptive starter strains.     

Microbial decontamination of medicinally important herbals using gamma radiation and their biochemical characterisation

A comprehensive study was carried out to assess the microbiological and biochemical characteristics of four herbals, namely, rose (Rosa centifolia), guggul (Commiphora mukul), chirata (Swertia chirayita), gulvel (Tinospora cordifolia) and four herbal formulations rasayan, shatpatryadi, scrub and kashayam. Total aerobic plate count (TAPC) was in the range of 3–7 log cfu/g, whereas, presumptive coliform count in many of these samples was in the range 2–6 log cfu/g. The IMViC (indole, methyl red, Voges-Proskauer, citrate) analysis and molecular characterisation (16S rDNA sequencing) ascertained the presence of Escherichia coli in some of the samples. A gamma radiation dose of up to 10 kGy was found to be sufficient for complete microbial decontamination without affecting the bioactive properties of herbal formulations, including antioxidant potential, which was high in rasayan, shatpatryadi, scrub, rose, and guggul. The antioxidant property of these herbals could be attributed to components such as phenolics, flavonoids and colour pigments.     

Evaluation of microbial survival post-incidence on fresh Mozzarella cheese

Commercial fresh Mozzarella cheese is made by direct acidification and is stored dry or in water without salt addition. The cheese has a shelf life of 6 wk, but usually develops an off-flavor and loses textural integrity by 4 wk, potentially due to the lack of salt and high moisture that allow the outgrowth of undesirable bacteria. To understand how microbial incidence affects cheese quality and how incident pathogen-related bacteria are limited by salt level during refrigerated storage, we made fresh Mozzarella cheese with high (2%) and low (0.5%) salt. The high-salt cheese was packaged and stored dry. The low-salt cheese was packaged and stored either dry or in 0.5% salt brine. One portion of cheeses was evaluated for surviving incident microbes by aerobic plate counts, coliform counts, and psychrophilic bacterial counts, of which coliforms and psychrophiles were not detected over 9 wk. Aerobic plate counts remained at 100 to 300 cfu/g up to 2 wk but increased by 1,000- to 10,000-fold between 4 and 6 wk at all salt levels and storage conditions. Other portions of cheeses were inoculated with either Escherichia coli or Enterococcus faecalis, both of which increased by 100-fold over 90 d of storage. Interestingly, E. coli added to the cheese brine first grew in the brine by 100-fold before attaching to the cheese, whereas Ent. faecalis attached to the cheese within 24 h and grew only on the cheese. We conclude that incident bacteria, even from similar environments, may attach to cheese curd and survive differently in fresh Mozzarella cheese than in brine. Overall, 2% salt was insufficient to control bacterial growth, and slow-growing, cold- and salt-tolerant bacteria may survive and spoil fresh Mozzarella cheese.     

New and classical spoilage bacteria causing widespread blowing in Argentinean soft and semihard cheeses

A total of 16 soft and semihard Argentinean cheeses, and 95 pasteurized cheese–milk samples, were analysed for microorganisms responsible for blowing. Lactic acid bacteria (starter microflora) resulted in high numbers (> 10⁷ colony‐forming units (cfu)/g). Coliform and yeast counts were lower than 10⁴ cfu/g. Cremoso cheeses were blown by leuconostocs, lactobacilli and Bacillus polymyxa. Mozzarella was spoiled by B. polymyxa and Bacillus macerans. Semihard cheeses were affected by spore‐forming (Clostridium and Bacillus), propionic and lactobacilli strains. Clostridia, Bacillus, leuconostocs and heterofermentative lactobacilli were detected in pasteurized milk. Bacillus strains were not previously associated with blowing in soft and semihard cheeses.     

The distribution of Enterobacteriaceae and some pathogenic micro-organisms in nonbranded white cheese samples sold in Ankara city

In this research, 75 samples of nonbranded white cheese, presented for sale in small markets from various regions and bazaars in Ankara, were studied. Eighty-six isolates, 71 of which are Gram-negative isolates and 15 of which are Gram-positive isolates, were obtained. These isolates were identified by using bioMérieux API20E and classical methods. Total mesophilic bacteria counts and total coliform bacteria counts were carried out for each white cheese sample. The total average mesophilic bacteria of 75 white cheese samples was 15.5 × 10⁵ cfu/g and the total average coliform bacteria were 13.6 × 10⁵ cfu/g.     

Effect of trehalose and lactose as cryoprotectant during freeze‐drying,in vitro gastro‐intestinal transit and survival of microencapsulated freeze‐dried Lactobacillus casei 431 cells

A novel microencapsulation technique for Lactobacillus casei 431 cells was developed, and the bacterial stability was studied. Cryoprotective solutes were incorporated in the encapsulation mix to improve freeze‐drying survival. The losses of viable cells during drying were recorded as 1.7, 0.84 and 0.38 log Colony‐forming units (cfu)/g for control and samples with trehalose and lactose, respectively. During the simulated gastric‐intestinal transit, trehalose and lactose contributed to higher survivals of 3.1 and 3.0 log cfu/g, respectively, in gastric fluid and 1.3 log and 0.9 log cfu/g, respectively, in 1% bile extract solution. Higher temperature storage was found to be detrimental for cell viability.     

Influence of Australian Native Herbs on the Maturation of Vacuum-packed Cheese

The composition, microbiology and biochemistry of semi-hard cheeses flavoured with native mint, lemon myrtle and bush tomato (BT) were compared with unflavoured (control) cheese during a 90-day period of maturation. Moisture, protein and salt levels of all cheeses were similar and did not change during maturation. However, the fat content of control cheese was significantly higher than that of the flavoured cheeses while the pH of cheese flavoured with BT was consistently lower throughout maturation. Total viable organisms, Lactobacillus and Lactococcus counts were between 10⁶ and 10⁷ colony forming units (cfu)/g cheese for all cheeses. Yeast and mould count was <10² cfu/g cheese throughout the maturation of all cheeses except in the cheese flavoured with BT which was >10³ cfu/g cheese. Biochemical indices of proteolysis and lipolysis increased with the extent of maturation in all cheeses but were most pronounced in the BT-flavoured cheese. The capillary electrophoretic profile of this cheese also indicated a more extensive hydrolysis of both α s- and β -caseins. The microbiological quality of BT appeared to have exerted a very significant influence on cheese properties.     

A traditional cheese from Greece to Turkey: Armola

In the present study, red capia pepper, broccoli, pumpkin, carrot purees and a probiotic culture containing Lactobacillus acidophilus were added to the conventionally produced Armola cheese to improve the functional properties of the cheese. The analyses showed that there were significant differences between the physicochemical and functional properties of the cheese samples. The samples containing broccoli had the highest antioxidant activity. Except for the control sample, L. acidophilus counts in Armola cheese samples were found to be 10⁶ log cfu/g on day 30 and the samples were found to maintain their probiotic properties until the end of the storage period.     

MODELLING of TIME-TEMPERATURE EFFECTS ON BACTERIA POPULATIONS DURING COOLING of CHEDDAR CHEESE BLOCKS1

Differences in cooling rate of Cheddar cheese from pressing (35C) to aging temperature (3.5–12C) has been reported to be responsible for flavor variation within a production lot. During aging, starter and nonstarter bacteria contribute extensively to flavor quality. Temperature effects on these bacteria were quantified using cheese from a local processor. At day 1, starter counts were 8 × 10⁷ cfu/g but as aging continued, starter counts decreased and non-starters became dominant. At 35C, starter counts reached 3 × 10⁶ cfu/g by day 3 and were below 10⁶ cfu/g by day 5. At 25, 20, 15 and 12C, starter bacteria were below 10⁶ cfu/g by day 10, 20, 24 and 40, respectively. Nonstarter counts, initially at 10⁴ cfu/g, reached = 10⁸ cfu/g at increasingly shorter times with higher temperatures. Kinetic analysis of growth in cheese and in a liquid medium suggested the possibility of diffusion growth limitations in cheese. Computer simulations for the growth of nonstarters suggests the individual cooling of small blocks (18 kg) would reduce the contribution of nonstarter counts to Cheddar cheese aging.