Physicochemical, sanitary and safety indicators changes during the ripening of Bulgarian white brined cheese from local farms (original) (raw)
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Acta agriculturae slovenica, 2004
The microbiological quality of 98 samples taken at some critical control points during the milking and processing of 14 semi-hard cheese made from raw cow milk by individual Slovenian producers was studied. The sampling points were: swabs from cows' udders, milking machines inner surfaces before and after milking, fresh raw and mixed milk from vats, whey immediately after curdling, brine, cheese after one month of ripening and after the following month of being kept vacuum packed at 6 °C. The high number of microorganisms on the inner surfaces of washed milking machines before milking revealed ineffective cleaning (washing) by about 60% of cheese producers. There were no seasonal differences in the number of microorganisms, except that the number of coliforms was higher in spring. The average of total number of microorganisms was 4.9•10 5 cfu/ml in raw milk and 5.5•10 6 cfu/ml in mixed milk from a vat (raw fresh milk mixed with milk kept for about 18-24 hours at room temperature), which did not grow significantly during cheese-processing. The number of coliforms in raw and mixed milk was in the range of 3.4•10 5 cfu/ml and fell to 5.4•10 4 cfu/ml in whey. The average number of enterococci, aerobic spore-forming microorganisms , yeasts and moulds, lactobacilli, lactococci, proteolytic and lipolytic microorganisms in milk and in whey were in the same logarithmic range of about 2.2•10 4 , 310, 3.5, 31.2•10 4 , 2.1•10 6 , 6.2•10 3 and 1.7•10 4 cfu/ml of the sample, respectively. Listeria spp. was isolated from 5.3% (cows' udders, milking machine, milk and whey), while none of the examined samples were positive to the presence of Salmonella spp. and Campylobacter spp. Proteus was present in 7 (7%) cases of milk and whey. Clostridia were detected in 10 (10%) samples (swabs, raw milk, whey). E. coli was isolated from 12 (12%) samples of swabs, raw and mixed milk, whey and brine. After one month of ripening the average total bacterial count was 9.2•10 7 cfu g-1 of cheese, of these 6.8•10 7 represented lactic-acid producers and 2.2•10 7 represented non-lactic acid producers. The average number of coliforms, enterococci, aerobic spore-forming microorganisms , yeasts and moulds, lactococci, lactobacilli, proteolytic and lipolytic microorganisms were 2.0•10 5 , 6.3•10 6 , 280, 960, 2.5•10 7 , 9.8•10 7 , 450 and 9.8•10 4 cfu g-1 of cheese, respectively. Salmonella spp., Listeria spp., Proteus, sulphitereducing clostridia and Campylobacter spp. were not detected in cheese samples. E. coli was found in 4 (30%) of samples while coagulase positive staphylococci were present in 9 (64%) of cheese samples. A high number of enterococci (from a min. 3.10 3 to a max. 15.10 7 cfu g-1) and coliforms (from a min. 10 to a max. 19.10 5 cfu g-1) were detected as well. After one month of keeping vacuum-packed ripened cheeses at 6 °C, the number of microorganisms did not rise significantly, except for the number of yeasts and moulds which grew to 3.6•10 4 cfu g-1 of cheese. Because of improper milking and processing hygiene conditions, three (21%) of the tested cheese samples did not correspond to the microbiological criteria according to the applicable regulations.
Bulletin of University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca. Veterinary Medicine, 2016
Raw milk represents a nutritive environment for a number of pathogens, like Salmonella spp., Escherichia coli O157: H7, Staphylococcus aureus etc. This fact can cause a serious of foodborne outbreaks associated to the consumption of contaminated milk and derivated products. The traditional processing of raw milk in poor hygiene conditions can pose a serious microbiological risk. The study aimed at evaluating the incidence of pathogen bacteria in ripened traditional cheese by advanced biochemical and molecular methods in order to reveal the possible risk of consumer exposure. The study was applied on 150 samples of riepened cheese from the follwoing types: salted teleme cheese and „Burduf” cheese and „Năsal” cheese. The traditional teleme cheese presented an average value of the total E. coli count in between 11.06±0.52-38.33±2.76 cfu/g. The risk represented by the presence of E. coli and Staphylococcus aureus is low within the first steps of ripening, being absent after 28 months of...
Le Lait, 1995
The microbial groups of technological interest (aerobic mesophilic flora, presumptive lactococci, presumptive lactobacilli, presumptive leuconostocs, presumptive enterococci, presumptive Micrococcaceae and mou Ids and yeasts) were enumerated throughout the ripening process in 4 batches of Armada goat's milk cheese (2 ripened in summer and 2 ripened in autumn). High counts of ail microbial groups were observed in milk (loglO cfu/g: aerobic mesophilic flora 6.72-7.55, presumptive lactococci 6.53-7.40, presumptive lactobacilli 4.84-5.05, presumptive leuconostocs 5.47-5.68, presumptive enterococci 2.9~.29, presumptive Micrococcaceae 4.47-4.66, mou Ids and yeasts 4.59-4.66); the highest counts being generally reached in ail the microbial groups in 1-week-old cheese. Beyond this, they progressively dropped until the end of ripening. In the first 8 weeks of ripening, no significant differences were observed in the counts related to the season when the cheeses were ripened. Only in 16-week-old cheeses were the counts in ripened cheeses during the summer lower than those determined in autumn ripened cheeses. The lactic acid bacteria were the most abundant flora during manufacturing and ripening of this cheese. Lactococci (Lactococcus lactis subsp lactis and Lactococcus lactis subsp cremoris) dominated in milk (50% of the isolates carried out in M17 agar), curd (70% of the isolates carried out in M17 agar) and 1-week-old cheese (70% of the isolates carried out in M17 agar) and lactobacilli (mainly Lactobacillus casei subsp casei and Lactobacillus plantarum) were the most abundant group during the last stages of ripening (92.5, 95 and 77.5% of the isolates carried out in Rogosa agar in 4-, 8-and 16-week-old cheese, respectively). M17 agar showed a moderate selectivity for the isolation of lactococci (45.71 % of the isolates carried out in M17 agar were classified as lactococci). The selectivity of MSE agar for the isolation of leuconostoc was very low (only 16.42% of the isolates carried out in MSE agar were c1assified as leuconostocs). On the other hand, Rogosa agar and KAA agar showed a very high selectivity for the isolation of lactobacilli and enterococci, respectively * Correspondence and reprints. l'abaissement du pH. Le salage ne semble pas en revanche avoir influencé les niveaux de population microbienne.
Bacteriological quality of on-farm manufactured goat cheese
Epidemiology and Infection, 1990
The bacteriological quality of 198 ripened soft or semi-soft goat cheeses obtained from dairy farms and the retail trade was investigated. The cheeses were examined for total counts of aerobic bacteria, coliform bacteria (37 and 44°C respectively), enterococci, coagulase positive staphylococci, Bacillus cereus and Clostridium perfringens. Cheeses obtained from dairy-farms were also determined for pH value. In terms of all tests performed, cheeses made of heat-treated milk with starter culture had the best prospects for fulfilling the criteria for 'fit for consumption'. Cheeses made of raw milk without starter culture made up the most unsatisfactory group from a food-hygiene point of view. Bacteriological guidelines for on-farm manufactured goat cheese are suggested.
Journal of Microbial & Biochemical Technology, 2016
The aim of this study was to evaluate the bacteriological quality and safety of fresh white cheese sold in Tripoli, Libya. The study lasted for approximately 7 months (November 2011-May 2012), during this period 87 fresh white cheese samples were collected from seven different areas (4 to 5 factories from each area with the rate of 3 duplicates). The samples were tested for temperature at receiving, pH and acidity, total aerobic counts, total coliform counts and the detection of incidence of some pathogenic bacteria including: Escherichia coli, Escherichia coli O157:H7, Staphylococous aureus, Salmonella spp., Aeromonas hydrophila and Listeria monocytogenes. Results indicated that the average temperature, % acidity, and pH of the tested samples were (15.80°C ± 5.8, 0.21 ± 0.02% and 5.81 ± 0.06) respectively. Data indicated that 70.1% of the samples exceeded the Libyan standard for white cheese No. 366 in respect to temperature, while pH of all samples was within the limits of such standard. On the other hand, means of total aerobic counts, total coliform counts, and the numbers of Staphyloccoccus aureus were (38 × 10 7 , 74 × 10 5 , 35 × 10 4 and 53 × 10 3 cfu/g) respectively of the study. b ia l & Bioc h e m ic a l Te chno lo g y
EDGARYAN, M. M., G. Y. IVANOV and D. P.RAKOV, 2007. Growth and activity of starter and adjunct lactobacilli and lactococci during ripening of two types Bulgarian white brine cheese. Bulg. J. Agric. Sci., 13: 177-183 The growth and activity of starter and adjunct lactobacilli and lactococci during ripening of two types Bulgarian white brine cheese were studied. The pasteurization of milk used was 72°C for 10 min and 85°C for 10 min. The temperature of cheese ripening was 12°C and 6°C respec- tively. The count of lactobacilli and lactococci and the changes in nitrogen fractions (NCN/TN - pH 4.6 soluble nitrogen/total nitrogen and NPN/TN - 12% CCl3COOH soluble nitrogen/total nitrogen) were determined at 10, 17, 24 and 31st day of the ripening of the cheeses. The results obtained showed difference in the growth of lactobacilli and lactococci. The higher temperature of pasteurization of the milk and the lower temperature of ripening of the cheeses had bigger negative influence on the gro...
2018
Microbiological changes in Keş cheese, traditional Turkish raw cow’s milk cheese made without the addition of starter culture, were studied during 90 days of ripening. Physico-chemical parameters, pH, salt content and water activity (aw), as important parameters for microbial growth, were also determined. Lactic acid bacteria were predominant microbial group. The time of ripening significantly influenced the count of total aerobic mesophilic bacteria, psychrophilic bacteria, mould (P<0.05), Lactobacillus spp. and Lactococcus spp. (P<0.01) which increased during ripening. E. coli and coagulase-positive staphylococci were not detected. The counts of Enterococcus spp. (P<0.05), Staphylococcus-Micrococcus spp., Enterobactericeae and coliform bacteria decreased throughout ripening of Keş cheese, which was connected to the physico-chemical parameters. Water activity significantly decreased (P<0.05), while the salt content increased (P<0.01) during ripening of Keş cheese. Th...
Microbiological quality of white-brined cheeses: a review
International Journal of Dairy Technology, 2002
White-brined cheeses are widely produced in the North-east Mediterranean area and the Balkans. Traditionally, they were manufactured as artisanal cheeses, and nowadays they are manufactured on an industrial scale, and rigorous control of the production and maturation processes is essential. Aspects of the microbiology of white-brined cheeses and their significance with respect to the quality and safety of the final products are discussed in this review.
Journal of food protection, 2007
Seventy raw milk cheeses made in different regions of Portugal, both hard and soft varieties, made with cow's, ewe's, or goat's milk or combinations of these, were sampled within their quoted shelf lives for microbiological safety. On the basis of the presence or numbers of Escherichia coli, E. coli O157, Staphylococcus aureus, Salmonella, and Listeria monocytogenes, cheeses were categorized as satisfactory, acceptable, unsatisfactory, or unacceptable and potentially hazardous. Twenty-two of the 70 cheeses were classified as satisfactory or acceptable. Thirty-seven of the cheeses were considered unsatisfactory because of the presence of E. coli, S. aureus, or both, while 11 of the cheeses were graded as unacceptable and potentially hazardous because of the presence of excessive numbers of S. aureus, E. coli, or L. monocytogenes and the presence of Salmonella in three of these. All cheeses graded as unacceptable and potentially hazardous were soft or semisoft cheeses made...
Journal of Dairy Science, 2012
The aim of this study was to evaluate the influence of different storage temperatures and delivery system of the milk on the microbiological and physicochemical characteristics of Grana Trentino, a long-ripened hardcooked Italian cheese. In particular, 3 kinds of milk storage and delivery were studied: milk delivered to the dairy in the traditional manner without temperature control, milk delivered at 18°C, and milk stored at the farm and delivered at 12°C. Milk, natural whey starter, and cheeses after 18 mo of ripening were sampled for microbiological profiles, physicochemical analysis, and proteolysis evaluation, and a study of cheese volatile compounds through a solid-phase microextraction gas chromatography-mass spectrometry technique was performed. Milk microbiota was not affected by any of the treatments. At the end of ripening, free fatty acid and ester contents were significantly higher in cheeses from milk without temperature control. This was probably due to the milk delivery to the dairy in churns causing the fat globule membrane break during transport and, consequently, a greater release of fat and deeper lipolysis. Milk refrigeration at 12°C for 12 h before delivery affected the distribution of nitrogen fractions in cheeses. Lower temperatures of milk storage favored a larger soluble nitrogen fraction and greater cheese proteolysis, probably caused by an enhanced plasmin activity. From this work, it is concluded that both milk temperature storage and transport system could affect cheese ripening, leading to significant differences in chemical compounds: if milk was delivered by churns, higher free fatty acid and ester content in cheeses was observed; if milk was stored at 12°C for 12 h before delivery, greater cheese proteolysis was induced with consequent faster ripening.