J. of Food and Dairy Sci., Mansoura Univ., Vol 10 (12):509 - 514 , 2019 Journal of Food and Dairy Sciences Journal homepage: www.jfds.mans.edu.eg Available online at: www. jfds.journals.ekb.eg Chemical, Microbiological and Sensory Evaluation of some Roquefort Cheese Existed in Egyptian Markets Abd El- Rahim, A. M.* Cross Mark Dairy Science Department Assiut University -Egypt ABSTRACT Eight blue-veined type cheeses (one domestic, seven imported Roquefort cheeses) were examined. Results showed that, % of fat and fat in dry matter ranged between (29 to 36) and (52.51 to 64.96), respectively. Moisture and total solids contents ranging between (39.44 to 45.02) and (54.98 to 60.56) respectively, while soluble nitrogen and amino nitrogen, were (42.51 and 50.48), (18.21 to 22.00) respectively. Total protein and its percentage in the dry matter, the results ranging between (18.66 to 23.00) and (31.22 to 43.60) respectively. the concentrations of both tyrosine and tryptophan acids ranged from (0.36 to 0.44) and (0.42 to 0.55). free fatty acids and volatile fatty acids, ranged from (33.00 to 70.00) and (15.00 to 42.00) . The microbial load ranged between (2.3 x 10 5 to 18.5 x 10 5). While fungi and yeasts ranged between (14.5 x 10 5 to 150.1 x 10 5) cfu. Coliform bacteria group and the anaerobic spore former bacteria had not been detected in all investigated cheese samples. study showed that the presence of roquefortin C in all cheese samples with a range of (1.9 to 5.21) with an average of 3.58, and the cheese samples number 3, 7, and 8 contained benicelic acid and were not detected in the rest of the samples, while the study confirmed that all samples, were completely devoid of both aflatoxin G1, M1, B2, and B2. Keyword: blue veined cheese , Roquefort cheese , mycotoxin , aflatoxin. INTRODUCTION flavor (Kinsella and Hwang, 1976). Blue-type cheeses are typically aged at 8 to 15 degrees Celsius for 60 to 90 days BIue or blue veined cheese (roquefort type) is semi (Karlin, 2011). A variety of blue cheeses worldwide, such soft or semi hard cheese represents a cheese type of as the very famous French Roquefort, English Stilton, considerable commercial importance in the United States Spanish Cabrales, Danish Danablue or Italian Gorgonzola, (Gripon, 1993)..A very broad definition for the blue veined industrials use specific strains of the fungal ascomycete cheeses would be, a cheese characterized in appearance species, Penicillium roqueforti. Originally, P. roqueforti and flavour by the growth and development of the fungal- was not inoculated while blue cheese manufacture but species, Penicillium roqueforti, either naturally or through contaminated the milk spontaneously with spores from the inoculation, that has a 4-5 % salt content, possesses a spicy, surrounding environment. Since the end of the 18th piquant flavour and a moist texture showing slight century, P. roqueforti asexual spores (conidia) are stickiness with a tendency to crumble (Kosikowski, 1970). inoculated into the cheese curd (Labbe and Serres 2009, During ripening period, blue veined cheeses 2004) at the beginning of the cheese-making process. undergo extensive proteins and lipids hydrolysis resulting Several methods have been applied to enhance the in odour, flavour, appearance and texture development quality of different types of cheese and accelerate their (Fox et al., 2000). Manufacture of blue veined cheese with ripening process, such as increasing the ripening typical and high quality flavor is mainly affected by milk temperature, addition of modified starter culture (heat type, species of moulds used, rate of starter growth and shocked), cheese slurry, trace elements as well as addition salt percentage. It is well known and established that of enzymatic mixtures (Hofi et al., 1973. Jolly and cheese ripening is a complex process involving the Kosikowski (1975) used microbial lipases to accelerate the hydrolysis of the curd by proteolysis, lipolysis and other development of blue cheese flavour . The production of enzymes-catalyzed reactions to give the flavor and texture blue-type cheese flavorings by submerged culture changes typical of the different cheese varieties. These fermentation has been well documented in patent and reactions are occurred by milk enzymes, rennet, starter scientific literature (Pratt 1989; Taylor 1995; Jolly and cultures, the moulds and yeasts and the cheese milk micro Kosikowski 1975; Dwivedi and Kinsella 1974). Typical flora (Kinsella and Hawng 1976). embodiments of Blue cheese flavoring production involve Blue-veined cheeses are unique among other the use of Penicillium roqueforti, a source of medium varieties in that holes are deliberately created to allow more chain. Blue-type cheeses are enjoyed around the world for oxygen to enter the cheese (Nelson, 1970). Oxygen their unique strong and piquant flavors. facilitates the growth and sporulation of P. roqueforti as well as the development of 6 characteristic Blue cheese * Corresponding author. E-mail address: [email protected] DOI: 10.21608/jfds.2019.77370 Abd El- Rahim, A. M. Lactic acid bacteria were reported to the dominant range from 0.05 to 1.47 mg/kg-1, while PR-toxin or group from salting on words, while moulds and yeasts penicillic acid could not detected in blue cheeses, Schoch were dominant during ripening (Lopez-Diaz et al., 1996) et al. (1984). Recent investigation showed that, Penicillium Penicillium roqueforti has been used as a secondary starter roqueforti do not produce these mycotoxin metabolites, culture for the ripening of blue–mould cheeses, such as but the closely related P. carneum and P. paneum produce Gorgonzola, Danabule, Roquefort, Bleu de Bresse and (Erdogan et al., 2003 and Samson and Frisvad, 2004). The Stilton for centuries. Because of the presented with lactic other microorganisms accompanying starters may be acid bacteria, Penicillium roqueforti is resistant to lactic present in mould cheeses The objectives of the present acid, acetic acid, carbon dioxide and several other lactic research were to determine the gross compositional acid bacterial intermediate metabolites (Boysen et al., constituents of a number of blue–type cheeses existed in 2000). The presence of mycotoxin in dairy products may Egyptian markets and to evaluate their nutritional values. be attributed to indirect contamination, which results from As well as to determine the incidence and the level of lactating animals ingesting contaminated feed and and some mycotoxins in blue cheeses samples collected in direct contamination, which occurs because of intentional order to evaluate its safety. or accidental growth of moulds on dairy products (Lafont MATERIALS AND METHODS et al., (1990) and (van Egmond 1989). Some of the fungal starters used in the cheese manufacture have been Eight blue- type cheeses samples were collected shown to produce various mycotoxins on culture media. P. from Egyptian local markets (2-6 months) the brand and roqueforti, widely used as a mould starter culture in the the description shown in Table (1) and Fig (1), Cheese blue cheeses, is known and fixed to produce Roquefortine samples were analyzed in duplicate, and they are stored at C, PR-toxin, mycophenolic acid and isofumigaclavins 4°C prior to analysis. all chemicals and reagents used in (Samson and Frisvad, 2004) and (Frisvad et al., 2004). this study were of analytical grade supplied by BDH and Roquefortine C had been detected in the cheeses with Sigma campanies. Table 1. The brand name and description of cheese: Brand Name No of samples Description and weight. Brand 1 Egyptian roquerort cheese 6 In triangles shape 100 g. Brand 2 Moby blue cheese 3 Cheese wheel (blue mark) 1Kg Brand 3 Danish Blue Cheese 3 Cheese wheel (blue mark) 1Kg Brand 4 Rosenborg Mellow Blue Danish Cheese. 6 Triangles shape 100 g Brand 5 Lady Bird Mellow 6 Triangle (Blue mark ) 100 g Brand 6 Moby blue cheese 6 Triangle (green mark) 100 g Brand 7 Rosenborg Danish Blue Cheese. 6 Triangle shaped 100 g Brand 8 Lady Bird 6 Triangle shaped (Golden mark) 100 g. Chemical analysis: Mycotoxins detection: Moisture ,Total solids content, titratable acidity, Mycotoxins extracted from cheese samples were soluble nitrogen measured using (micro-kjeldahl method), determined by thin layer chromatographic technique on amino nitrogen, and ash were estimating according to pre-coated silica gel plate 60 F254 (Merck) as described by A.O.A.C (2000) .The total protein was calculated as TN % El-Kady and Moubasher (1982). Mycotoxins were x 6.38 (Plummer, 1988). Fat content estimated using identified by comparison with appropriate reference Gerber method according to Ling (1963). The salt contents standards of mycotoxins using solvent system of were determined by using the "Mohr method" of A.P.H.A chloroform: acetone (90:10, v/v) for Aflatoxins. (2004). Total volatile fatty acids(TVFA) and Free fatty acids (FFA) were determined by the method of Organoleptic properties:- Kosikowski (1977). Tyrosine and tryptophane were Panel test of cheese samples was carried out spectrophotometrically determined by the method according to El-Hofi et al., (1991) as in the following described by Vakaleris and Priee (1959). system, flvour 50. Body & Texture 40 and general Bacteriological analyses: appearance 10 points The panel test was carried out by 10 Samples preparation and dilutions for the panelist from both Dairy science Department , Assuit microbiological examinations were carried out according University. to IDF standards (1996). Total Bacterial Count (T.B.C.) in RESULTS AND DISCUSSIONS cheese samples was determined with the standard plate count technique according to A.P.H.A., (2004). The The gross chemical composition in eight blue- presence of coliform bacteria was examined by the mould cheeses are shown in Tables (2), from the data it multiple tube technique, the sample dilutions were was observed that the titratable acidy and PH values of inoculated into MacConky broth medium according to cheese varied from 2.17% with corresponding PH values of (Difco manual, 1998).