共查询到20条相似文献,搜索用时 31 毫秒
1.
ABSTRACT: The effect of feta cheese manufacture on aflatoxin M1 (AFM1 ) content was studied using an enzyme immunoassay technique. Feta cheese was made from milk spiked with 1 and 2 μg AFM1 per kilogram milk. Pasteurization at 63 °C for 30 min caused <10% destruction of AFM1 . During cheese making, the remaining AFM1 in milk was partitioned between curd and whey with two-thirds retained in the curd and one-third going into the whey. Cheeses were then stored for 2 mo in 8%, 10%, and 12% brine solutions at 6 and 18 °C. There was a 22% to 27% reduction of AFM1 during the first 10 d of storage, with slightly more loss as salt concentration increased and when the cheese was stored at 18 °C. Further storage caused only slight decrease in AFM1 and after 30 d of brining there was no difference in AFM1 content of the cheese based upon salt concentration of the brine. At 18 °C, no further losses of AFM1 occurred after 30 d, and at 6 °C, there was continued slight decrease in AFM1 levels until 50 d. After 60 d of brining, there was a total loss of 25% and 29% of the AFM1 originally present for cheese brined at 6 and 18 °C, respectively. Thus, the combination of pasteurization, conversion of milk into feta cheese, and at least 50 d storage of cheese in brine caused a total loss of about 50% of the AFM1 originally present in the raw milk. 相似文献
2.
A. M. Elgerbi K. E. Aidoo A. A. G. Candlish R. F. Tester 《Food Additives & Contaminants》2004,21(6):592-597
Forty-nine samples of raw cow's milk and 20 samples of fresh white soft cheese were collected directly from 20 local dairy factories in the north-west of Libya and analysed for the presence of aflatoxin M1 (AFM1). The samples were analysed using a high-performance liquid chromatography technique for toxin detection and quantification. Thirty-five of the 49 milk samples (71.4%) showed AFM1 levels between 0.03 and 3.13 ng ml-1 milk. Multiple analyses of five milk samples free of AFM1 artificially contaminated with concentrations of AFM1 at 0.01, 0.05, 0.1, 1.0 and 3.0 ng ml-1 showed average recoveries of 66.85, 72.41, 83.29, 97.94 and 98.25%, with coefficients of variations of 3.77, 4.11, 1.57, 1.29 and 0.54%, respectively. Fifteen of 20 white soft cheese samples (75.0%) showed the presence of AFM1 in concentrations between 0.11 and 0.52 ng g-1 of cheese. Multiple assays of five cheese samples free of AFM1 spiked with different concentration of AFM1 (0.1, 0.5, 1.0 and 3.0 ng g-1) showed average recoveries of 63.23, 78.14, 83.29 and 88.68%, with coefficients of variation of 1.53, 9.90, 4.87 and 3.79%, respectively. The concentrations of AFM1 were lower in the cheese products than in the raw milk samples. 相似文献
3.
The aim of this study was to detect the presence of aflatoxin M1 (AFM1) in samples of raw milk (n = 38), UHT milk (n = 12), white pickled cheese (n = 50), and yogurt (n = 50) collected from the ?anl?urfa city markets and locally produced dairy products by ELISA. The mean contamination rates were 56.74 ± 40.32, 43.1 ± 23.19, 103.2 ± 29.13, and 55.28 ± 12.68 ng/kg, respectively, for raw milk, UHT milk, white pickled cheese, and yogurt. According to the data, 21 (55%) raw milk, 3 (25%) UHT milk, 10 (20%) white pickled cheese, and 10 (20%) yogurt samples were contaminated with AFM1 over the acceptable levels (≥50 ng/kg), ranging from 0.82 to 130.89 ng/kg. None of the white pickled cheese samples contained AFM1 levels above the Turkish legal limit (250 ng/kg). Consequently, the AFM1 contamination levels determined in this study in white pickled cheese were not considered to pose a serious public health hazard. However, the AFM1 levels in raw and UHT milk and yogurt samples indicate an increased human health risk in Turkey related to high aflatoxin levels. Therefore, milk and dairy products have to be monitored by the Turkish public health authorities continuously to detect AFM1 contamination. 相似文献
4.
FATMA SAHINDOKUYUCU KOCASARI FULYA TASCI FIRDEVS MOR 《International Journal of Dairy Technology》2012,65(3):365-371
The aim of this study was to investigate the occurrence of aflatoxin M1 (AFM1) in dairy product samples in Burdur city. A total of 315 samples of dairy products were collected during 2008. Of the 315 samples analysed, AFM1 in 246 samples (78.1%) was found to range from 5.5 to 800 ng/kg. In addition, AFM1 levels of 16 raw milk, two pasteurised milk, only one milk powder and three white cheese samples were above the Turkish Food Codex. It is concluded that the occurrence of AFM1 in dairy products may be considered as a possible hazard for public health. 相似文献
5.
Rahoma S. Mohamed Guilherme B. M. Neves & Theo G. Kieckbusch 《International Journal of Food Science & Technology》1998,33(5):445-454
Cholesterol reduction together with the fractionation of triglycerides in butter oil was obtained using a combined supercritical CO2 extraction/alumina adsorption process in a high-pressure apparatus that allows the independent control of temperature and pressure. Cholesterol levels in butter oil fractions extracted at 40 °C and 27.6 MPa were reduced from 2.5 to 0.1 mg g−1 of oil. Butter oil was also fractionated into low-, intermediate- or high-molecular-weight triglycerides. This single-stage combined process is a clear indication of the important technological possibilities with a more efficient multistage fractionation followed by the subsequent blending and formation of desired milk fat products. A comparison of solubility data of pure cholesterol in CO2 with those for cholesterol contained in butter oil revealed the co-solvency effects of triglycerides on the solvation of cholesterol. 相似文献
6.
GÜVEN URAZ SERPIL BOLAT EBRU YILMAZ EMEL SEZGN 《International Journal of Dairy Technology》2009,62(2):255-259
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. 相似文献
7.
HASAN TEMZ UMUT AYKUT ABDULKADR K HURT 《International Journal of Dairy Technology》2009,62(3):378-386
In this study, the shelf life of Lor cheese stored under different atmosphere compositions was assessed and compared. Lor cheeses were held in four different atmospheres containing: vacuum packaging (VP), 40% CO2 /60% N2 , 60% CO2 /40% N2 and 70% CO2 /30% N2 (modified atmosphere packaging). Control cheeses were stored in air. All cheese samples were kept in the refrigerator at 4°C for 45 days and investigated for physicochemical, microbiological and sensory properties. The acidity index value was significantly higher ( P < 0.05) in the control and vacuum packaged samples than in those stored for the same period under CO2 . Microbiological results showed that modified atmosphere packaging delayed microbial growth compared with air and VP samples. Of the three modified atmospheres, gas mixtures 60% and 70% CO2 were the most effective for inhibition of growth of micro-organisms. Sensory evaluation (odour and taste) results showed that Lor cheese packaged under modified atmosphere packaging (60% CO2 /40% N2 and 70% CO2 /30% N2 ) retained good characteristics for 45 days of storage, while vacuum and control samples were sensorily unacceptable after 10 days of storage. 相似文献
8.
Ali Gücükolu T. Onur Kevenk Tolga Uyanik
zgür adirci Gknur Terzi Mustafa Aliarli 《Journal of food science》2012,77(11):M620-M623
Abstract: The aim of this study was to investigate the prevalence of enterotoxigenic Staphylococcus aureus in 122 samples, including 60 raw milk, 32 white cheese, 10 kashar cheese, 10 butter, and 10 ice cream samples obtained from Samsun province, Turkey. In this study, S. aureus was detected in 64 samples, including raw milk (45/60; 75%), white cheese (12/32; 37.5%), kashar cheese (3/10; 30%), butter (3/10; 30%), and ice cream (1/10; 10%) samples. A total of 81 isolates were identified as S. aureus by PCR with the presence of 16S rRNA and nuc genes. The presence of genes encoding the staphylococcal enterotoxins (SEs) SEA, SEB, SEC, and SED was detected by multiplex PCR. According to the analysis, seven isolates from the raw milk samples (7/51; 13.7%) were enterotoxigenic; five of them produced SEA (5/7; 71.4%), one produced SEB (1/7; 14.2%), and one produced SEA+SEB (1/7; 14.2%). Four isolates from the white cheese samples (4/21; 19%) produced the SEA (1/4; 25%), SEC (1/4; 25%), SED (1/4; 25%), and SEA+SED (1/4; 25%) toxins. Two isolates from the kashar cheese samples (2/4; 50%) were found to be enterotoxigenic; one produced SEA (1/2; 50%) and the other produced SED (1/2; 50%). One isolate from the butter samples (1/4; 25%) showed enterotoxigenic character (SEB, 1/1; 100%). The products were found to be potentially hazardous to public health because of the fact that levels of contamination were higher than 105–106 cfu/g ml in 39% (25/64, 17 raw milk, 7 white cheese, and 1 butter) of the analyzed samples. 相似文献
9.
HAMID MOHAMADI MOHAMAD ALIZADEH JAMSHID RAHIMI SHAHAB QASRI 《International Journal of Dairy Technology》2010,63(2):262-265
The purpose of this survey was to evaluate the natural occurrence and content of aflatoxin M1, AFM1, in dairy products marketed in Urmia. During September 2007, 40 samples of pasteurised milk, 40 samples of ultra high temperature‐treated (UHT) milk, 40 samples of creamy cheese and 40 samples of Iranian Feta cheese were collected from different supermarkets in Urmia city. AFM1 contents were determined by the competitive enzyme‐linked imunosorbent assay (ELISA) technique. All milk samples analysed showed a mean of AFM1 concentrations lower than the permissible level of 50 ng/kg in Iran (23.22 and 19.53 ng/kg in pasteurised milk and UHT milk respectively). The mean levels of AFM1 contamination were 43.31 ng/kg in Feta cheeses and 21.96 ng/kg in creamy cheeses. The potential risk of human exposure to aflatoxin M1 via consumption of milk and milk products is well known. Dairy products must therefore be evaluated for aflatoxin and kept free from fungal contamination as much as possible. 相似文献
10.
Twenty-four Murrah buffaloes (60 days pre-partum) were divided into four equal groups (T 1 , T 2 , T 3 and T 4 ) and were supplemented with 0, 1000, 1500 and 2000 IU α-tocopheryl acetate per day up to 30 days of lactation, and half of these doses from 30 to 60 days of lactation. Milk samples collected fortnightly were analysed for vitamin E, fat, and development of oxidized flavour, with and without copper addition by a panel of judges, and chemically by the thiobarbituric acid test. Scores for oxidized flavour ranged from 0 to 10 with 0–4 as definite, 5–7 as light and 8–10 having no defect. The α-tocopherol content in milk fat (µg/g) averaged 20.55, 25.56, 29.98 and 31.38 in T 1 , T 2 , T 3 and T 4 groups, respectively. The addition of Cu in the milk significantly increased milk fat oxidation. Better stability of milk in T 3 and T 4 groups was observed, which might be due to a higher level of milk α-tocopherol. Addition of 1500 IU α-tocopheryl acetate in the diet of buffaloes helped in improving the oxidative stability of milk. 相似文献
11.
Aflatoxins are toxic fungal metabolites, which can be found in feed. Aflatoxin M1 (AFM1) is excreted into milk when ruminants ingest aflatoxin B1 contaminated feedstuffs. Due to its carcinogenic potential, contamination of milk and dairy products with AFM1 may pose a risk for consumers. Hence, it is considered a public health concern. In this survey, the level of AFM1 contamination of dairy products marketed in Costa Rica was determined by enzyme-assisted extraction, immunoaffinity clean-up and high-performance liquid chromatography coupled with a fluorescent detector (HPLC-FLD) in fluid milk (n = 70), fresh cheese (n = 70) and sour cream (n = 70) collected at local convenience stores and supermarkets. AFM1 concentrations in milk and fresh cheese ranged from 19 to 629 ng/L and from 31 to 276 ng/L, with mean values of 136 ng/L and 74 ng/L, respectively, whereas none of the sour cream samples analysed tested positive for this aflatoxin. In 30 milk samples, and 10 cheese samples, AFM1 concentrations surpassed threshold concentrations as established by the European Commission. Thus, sour cream and – to a lesser extent – cheese manufacturing seems to reduce the amount of AFM1 present in milk, possibly due to fraction redistribution or microbiological degradation. The survey results reveal improper quality control procedures in the Costa Rican dairy industry. Therefore, a surveillance programme for dairy products in our country is recommended. 相似文献
12.
Ali Adnan Hayaloglu 《International Journal of Food Science & Technology》2009,44(7):1388-1394
Twelve samples of raw milk mature Kashar cheese at different stages of ripening were collected from retail outlets. The average pH, moisture, fat-in-dry matter, protein, salt-in-dry matter and titratable acidity contents of the samples were 5.33, 39.39%, 45.20%, 27.33%, 6.62% and 0.65% (as lactic acid), respectively. Indices of proteolysis varied from 10.72% to 23.75% and 7.09% to 12.26% for pH 4.6-soluble and 12% trichloroacetic acid-soluble nitrogen fractions, respectively, and total free amino acid concentrations ranged from 6.36 to 36.03 mg Leu g−1 of cheese. The cheeses were analysed for volatile compounds by Solid Phase Microextraction and Gas Chromatography-Mass Spectrometry (GC-MS). A total of 113 compounds were detected and identified belonging to the following chemical groups: acids (eleven), esters (sixteen), ketones (sixteen), aldehydes (six), alcohols (twenty-seven), sulphur compounds (seven), terpenes (seven) and miscellaneous compounds (twenty-three). The potential effect of each compound on the flavour profile of Kashar cheese is discussed. Acids, esters, ketones and alcohols were found at considerable levels in the samples. Kashar cheeses obtained from different retail outlets displayed some differences in terms of chemical composition, proteolysis and patterns of aroma compounds; and may be attributed to their production technologies and age-related variations. 相似文献
13.
Antonia M. Jiménez Maria Antonia Murcia Pilar Parras & Magdalena Martínez-Tomé 《International Journal of Food Science & Technology》2008,43(8):1464-1473
The antioxidant activity of several dairy products, yoghurt enriched with green tea and lemon, fermented milk, yoghurt with strawberry pulp, 'low-calorie' yoghurt with inulin and milk enriched with vitamin E and their ingredients were analysed. Yoghurt enriched with green tea and lemon showed the best lipidic antioxidant capacity. All the dairy products analysed were very good OH· radical scavengers. The dairy products analysed were unable to scavenge H2 O2 except green tea. The antioxidant activity of these samples resisted high temperatures in the Rancimat test; of the ingredients analysed, the best antioxidant activity was found for vitamin E followed by green tea, pectin, Lactobacillus acidophilus , lemon pulp and cornstarch. Antioxidant activity did not suffer variations during storage at an unfavourable temperature (40 °C), as demonstrated by the linoleic acid assay. Yoghurt enriched with green tea and lemon, yoghurt with strawberry pulp and low-calorie yoghurt with inulin produced the best results in the Trolox equivalent antioxidant capacity (TEAC) assay. 相似文献
14.
Arafa M. S. Meshref Walaa A. Moselhy Nour El-Houda Y. Hassan 《Sensing and Instrumentation for Food Quality and Safety》2014,8(4):381-388
Milk and dairy products are an important food in the human diet. The present investigation was carried out to determine concentrations of lead, cadmium, zinc, copper and iron in milk and dairy products and evaluate the potential health risks of metals to humans via consumption of milk and dairy products. A total of 77 samples of milk and dairy products (22 raw milk, 20 kareish cheese, 21 butter and 14 rice pudding) were collected from farms, individual farmers and dairy shops in Beni-Suef governorate, Egypt. Pb, Cd, Zn, Cu and Fe concentrations in milk and dairy products ranged from 0.044–0.751, 0.008–0.179, 0.888–18.316, 0.002–1.692 and 1.3208–45.6198 ppm respectively. Pb concentration in all samples exceeded the maximum permissible limit (0.02 mg/kg) established by codex standard. Pd and Cd intake through milk and dairy products consumption were 1.27 and 0.33 μg/kg bw/day, which represent 35.3 and 39.8 % of the tolerable daily intake. Dairy products are poor sources of iron, copper and zinc, and milk contributes little to the total iron and zinc intake. Target hazard quotient values of less than 1 indicate a relative absence of health risks associated with the consumption of milk and dairy products. 相似文献
15.
Three hundred and thirty-eight samples of milk and milk products in Ankara were screened for the presence of motile Aeromonas species. The overall frequency of aeromonads in these samples was 27%. As expected, raw milk samples were more contaminated with aeromonads than were other products. Sixty-five (49.2%) of the 132 bulk raw milk samples were contaminated with aeromonads. In 35 of these samples, populations of aeromonads from 1.5 × 102 to 3.0 × 103 cfu/mL were counted in ampicillin dextrin agar (ADA). Ten (40%) of the 25 raw milk samples sold in the street were contaminated with aeromonads. In eight of these samples, 1.2 × 102 −3.0 × 103 cfu/mL were counted. Five (16%) of the 31 pasteurized milk and 12 (8%) of the 150 white cheese samples were contaminated with Aeromonas spp., but no countable aeromonads population was noted in ADA. The incidence of A. hydrophila, A. sobria and A. caviae in all samples was found to be 90.2%, 4.3% and 5.4%, respectively. The majority of the strains identified as A. hydrophila and A. sobria were able to produce haemolysin, protease and DNase, while strains identified as A. caviae were only positive for DNase. All isolated Aeromonas species ( A. hydrophila, A. sobria and A. caviae ) were positive for uptake of Congo red dye. Nevertheless, only strains identified as A. hydrophila and A. sobria showed a high rate of positive results when tested for the production of the Voges–Proskauer reaction and lysine decarboxylase. The results of this work show that motile Aeromonas spp., especially A. hydrophila , are frequently found in these samples. As these products are usually commonly consumed in Ankara, they can pose a risk especially for children, the elderly and immunocompromised individuals. 相似文献
16.
M BARBARA PISANO M ELISABETTA FADDA MAURA DEPLANO ARIANNA CORDA SOFIA COSENTINO 《International Journal of Dairy Technology》2006,59(3):171-179
The purpose of this study was to assess the chemical and microbial characteristics of 12 batches of artisanal Fiore Sardo, a protected designation of origin (PDO) hard cheese made from raw ewe's milk without addition of starters, during maturation. High standard deviations were observed for moisture percentage, total solids percentage and NaCl percentage content, possibly owing to differences in manufacturing processes and/or milk composition. Total mesophilic bacteria varied between 10 log10 cfu/g in 48-h-old cheese samples and 3 log10 cfu/g in 9-month-old samples. Total coliforms and staphylococci showed the highest counts at 48 h of ripening then decreased significantly, dropping to levels below 2 log10 cfu/g at 3 months of maturation. Lactic acid bacteria and enterococci were the dominant micro-organisms throughout maturation. They were mainly represented by the species Lactococcus lactis ssp. lactis, Enterococcus faecium, Lactobacillus plantarum and Lactobacillus casei group. Low levels of yeasts were detected throughout the maturation period of the cheese. Debaryomyces hansenii and Kluyveromyces lactis var. lactis were the prevalent yeast species isolated. 相似文献
17.
Bogumia Pilarczyk Agnieszka Tomza-Marciniak Anna Mituniewicz-Maek Marta Wieczorek-Dbrowska Renata Pilarczyk Jerzy Wójcik Aleksandra Balicka-Ramisz Magorzata Bkowska & Izabela Dmytrów 《International Journal of Food Science & Technology》2010,45(1):186-191
The aim of the study was to determine Se concentration in selected products of animal origin (dairy products, pork, beef, chicken, giblets, fish, eggs) and to estimate the degree to which these products cover daily Se requirement in humans. Selenium concentrations were determined using the spectrofluorometric method. Mean Se concentration in the milk, yoghurt, kefir, and probiotic drinks was 0.020 μg mL−1 , 0.010 μg mL−1 , 0.012 μg mL−1 and 0.012 μg mL−1 , respectively. Selenium concentration in cheese ranged 0.022–0.088 μg g−1 wet weight. The average selenium content of meat ranged from 0.064 (beef) to 0.094 (chicken) μg g−1 w.w. The mean Se content of giblets (liver: 0.307–0.401 μg g−1 w.w.) was significantly ( P < 0.05) higher than in meat. The concentration of Se depends on fish species and in our study it ranged from 0.136 ± 0.023 (flounder) to 0.282 ± 0.024 μg g−1 w.w. (mackerel). The results obtained show that the analysed food provides 22.8% of the daily selenium requirement. Considering that animal products account for 40–45% of the diet daily selenium intake averages 33–37 μg. 相似文献
18.
Anna Maria Sanguinetti Nicola Secchi Alessandra Del Caro Giuseppe Stara Tonina Roggio & Antonio Piga 《International Journal of Food Science & Technology》2009,44(6):1192-1198
This study evaluated the shelf life extension of a cheese cake subjected to modified atmosphere (MAP) and active packaging (AP). Cheese cakes were packaged under different N2 /CO2 ratios (70/30 and 20/80) (MAP batches), by placing a sachet of an iron oxide-based oxygen absorber inside trays (AP batch) and with air (air batch). Changes in microbial growth, in-package gas composition, chemical–physical parameters including texture and sensory attributes were monitored for 48 days at 20 °C. AP allowed a mould-free cheese cake shelf life of 48 days, MAP extended the shelf life of samples packaged under 30% and 80% CO2 up to 14 and 34 days, respectively, whereas tarts stored with air spoiled after 7 days. MAP resulted in a significant increase in hardness after 14 days of storage, whereas AP tarts recovered the initial texture after 48 days. Panellists judged AP tarts over the acceptability threshold during the whole shelf life of cheese tarts. 相似文献
19.
The effect of addition of pregastric lipase enzyme on the accelerated ripening of white pickled cheese was investigated. Commercial pregastric lipase was added to milk before rennet addition at a level of 0,5, 8, 11 g per 100 L of milk and cheeses were made from this milk. Total solids, fat, total nitrogen, salt, titratable acidity, pH and free fatty acids (C2 -C18:1 ) were analysed in the samples during 1–90 days of ripening period at 15 days intervals. Total solids, fat, total nitrogen, salt, titratable acidity, and pH of cheeses slightly increased during the ripening period. Free fatty acids and volatile free fatty acid contents in cheeses made from pregastric lipase added milk were affected by pregastric lipase and their contents were increased significantly (P<0.01) during the ripening period. Particularly, when cheese had a high level (11 g per 100 L milk) pregastric lipase, the amounts of butyric, caproic and caprylic acids in white pickled cheese were quite high. The relative amounts of volatile free fatty acids varied with storage time and pregastric lipase levels. 相似文献
20.
Hilal Colak Hamparsun Hampikyan Beyza Ulusoy Ozer Ergun 《European Food Research and Technology》2006,223(6):719-723
AFM1 is a hydroxylated metabolite produced when ruminants ingest contaminated feed with AFB1 and transferred to dairy products such as cheese, which represents an important risk factor for consumers. Turkish White, Kashar and Tulum cheeses are traditional cheese types in Turkey. This study was planned to compare the performance of a competitive ELISA for the determination of AFM1 in Turkish White, Kasar and Tulum cheeses against a new HPLC method. For this purpose, different AFM1 concentrations (50–400 ng/kg) were added to the cheese samples and the toxin levels were determined by ELISA and HPLC. Also, both methods were performed in 24 real samples obtained from different markets. In conclusion, the results obtained by ELISA in this study were related to those by HPLC for AFM1. 相似文献