Journl of Advnces in Microiology 2(3): 1-7, 2017; Article no.jamb.33152 SCIENCEDOMAIN interntionl www.sciencedomin.org Microiologicl Chrcteristics of White Cheese (Gin yd) Mnufctured under Trditionl Conditions Mohmed Osmn Mohmed Adll 1* nd Husn Eis Ahmed Omer 2 1 Deprtment of Diry Production, Fculty of Animl Production, University of Khrtoum, Shmt P.O.Box 32, Postl Code 13314, Khrtoum North, Sudn. 2 Ministry of Agriculture, Animl Resources nd Rurl Development, North Kordofn Stte, Sudn. Authors contriutions This work ws crried out in collortion etween oth uthors. Author MOMA performed the sttisticl nlysis nd wrote the first drft of the mnuscript. Author HEAO designed the study, mnged the nlyses of the study nd the literture serches. Both uthors red nd pproved the finl mnuscript Article Informtion DOI: 10.9734/JAMB/2017/33152 Editor(s): (1) Pongsk Rttnchikunsopon, Deprtment of Biologicl Science, Fculty of Science, Uon Rtchthni University, Uon Rtchthni 34190, Thilnd. Reviewers: (1) Anonymous, Croti. (2) Ayse Deniz Crdk, University of Adnn Menderes, Turkey. (3) Monik Thkur, Amity University, Noid, Indi. (4) Michel U. Ukwuru, Federl Polytechnic, Kogi Stte, Nigeri. Complete Peer review History: http://www.sciencedomin.org/review-history/18828 Originl Reserch Article Received 31 st Mrch 2017 Accepted 20 th April 2017 Pulished 27 th April 2017 ABSTRACT Aims: This study ws conducted to evlute the qulity control of white cheese (Gin yd) processing in trditionl plnts. White cheese ws mnufctured using rw cow milk from two res in North Kordofn (Rish nd Czgil). Methodology: Smples were collected from four stges of cheese mnufcture (rw milk, curd efore nd fter, cheese delivered to the mrket). Smples were collected in sterile plstic gs stored t 4 C in ice ox nd trnsported to the lortory of Kordofn University for nlysis. Rw milk nd cheese were microiologiclly (totl vile cteri, Stphylococcus ureus, coliform cteri, lctocilli cteri, yests nd moulds) evluted during processing stges. Results: the results showed tht ll microorgnisms tested were not significntly ffected y the re in which cheese ws mnufctured. During the processing stges, coliform cteri count *Corresponding uthor: E-mil: uthny@yhoo.com;
Adll nd Omer; JAMB, 2(3): 1-7, 2017; Article no.jamb.33152 ws significntly (P<0.001) higher in curd efore nd fter (log 7.31 cfu/gm nd log 7.30 cfu/gm respectively) compred to cheese delivered to the mrket. Yests nd moulds count ws significntly (P<0.05) higher in curd fter (log 4.08 cfu/gm). Totl vile cteri, S. ureus nd lctocilli counts were not significntly ffected y the stge of cheese processing. Conclusion: The microiologicl count of rw milk ws high except yests nd moulds, nd the qulity of cheese deteriorted fter curd then slightly improved in cheese delivered to the mrket. Keywords: Gin yd; microiologicl; trditionl plnts; rw milk. 1. INTRODUCTION Trditionl white pickled cheese (Gin Byd) of the Sudn is product mde from rw milk to which slt (6-20%) hs een dded without the use of strter culture [1,2]. Cheese mking in Sudn is sesonl ctivity eing mnufctured during the riny seson where plenty of milk is ville. The procedure of mnufcturing white cheese in different res in the country is similr with slight vritions [3]. It is crried out y collection of milk from producers or sellers in iron or plstic rrels, nd slting the milk t the rte of 5-20% ut in winter, milk is heted to 38-40 C prior to slting. Rennet tlets (1 tlet/45 L milk) re dissolved in tp wter nd dded to milk, nd the mixture is left undistured for 5 6 hr until cogultion occurs. The curd is then cut nd trnsferred to moulds lined with cheese cloth nd pressed overnight to drin whey which is collected to e used lter for preservtion. The curd is removed from the moulds, cut into smll cues nd preserved in the whey in tins seled with soldering or in plstic rrels tightly covered to prevent oxidtion [4]. The microiologicl qulity of white cheese cn e influenced y numerous fctors such s the qulity of milk, the use of psteuriztion or thermiztion, vrious technologicl prmeters, the level nd type (s) of microil contmintion tht occur throughout the mnufcture nd the storge of cheese [5]. Recent studies hve shown tht rtisnl cheeses hve different nd typicl microil popultion dynmics relted to the locl processing technology nd geogrphicl origin [6]. Suliemn et l. [7] studied the impct of comintion of lctic cid cteri nd yests in the fermenttion of Jin-eid nd found tht totl cteri nd yests nd moulds counts of Jin eid mde with strter culture (comined strter of Lctocillus plntrum, Streptococcus thermophillus nd Kluveromyces lctis) were 2.85 10 5 nd 5.0 10 2 cfu/g, respectively, coliform cteri, Slmonell spp. nd Stphylococcus ureus cells were not found. Due to the trditionl method of mnufcturing Gin yd in Sudn, it is necessry to evlute the cheese mnufctured under these conditions in order to suggest the ccurte methods of improvement of the cheese. Therefore, this study ws imed to evlute the microiologicl qulity of the cheese mnufctured in trditionl plnts during the steps of mnufcture until delivery to the mrket. 2. MATERIALS AND METHODS 2.1 Cheese Mnufcture Cheese ws mnufctured in Rish nd Czgil res (trditionl plnts for Gin yd mnufcture) which re locted 20 km nd 30 km, respectively from El Oeid city, North Kordofn Stte. Cheese ws mnufctured s follows: the temperture of milk ws recorded (35 C), nd then slt ws dded t the rte of 6-8 kg/50 L milk. Rennet powder ws dissolved in 5 ml wter nd dded to milk (1.5 g/50 L milk), stirred for 5 min nd left undistured to develop curd. After complete cogultion (3 hr), the cogultion time ws recorded nd the curd ws scooped into wooden moulds lined with cheese cloth. The curd ws pressed (out 5 kg weight) overnight. Next dy the curd ws removed from the moulds, nd the whey ws collected nd oiled to remove cheese prticles, which were used for the mnufcture of mish, nd the whey left fter mish mnufcture ws used for cheese preservtion. The cheese ws cut into smll cues nd immersed into the whey nd pckged. 2.2 Smple Collection nd Anlysis During mnufcture of cheese till delivery to the mrket, the smples were collected s follows: rw milk; curd efore ; curd fter ; cheese delivered to the mrket. Milk (10 smples from ech re) nd cheese (10 smples from ech stge) were collected in 2
Adll nd Omer; JAMB, 2(3): 1-7, 2017; Article no.jamb.33152 sterile plstic gs stored in ice ox, trnsported to the lortory nd stored t 4 C till exmintion which ws crried out immeditely on rrivl to the lortory or within 24 hr. The experiment ws crried out in triplicte. 2.3 Microiologicl Exmintion 2.3.1 Preprtion of smple dilutions A representtive smple of 11 g cheese ws homogenized in 99 ml sterile peptone wter to mke 10-1 dilution, then seril dilutions of 10-2 10-7 were prepred [8]. 2.3.2 Totl vile cteri count Spred plte method on plte count gr medium ws used, nd the dishes were inverted nd incuted t 25 C for 48±2 hr [8]. 2.3.3 Coliform cteri count McConkey gr medium ws used for the enumertion of coliform cteri. The specified dilutions were deposited onto the medium nd spred over the surfce of the gr, the dishes were then inverted nd incuted t 37 C for 48±2 hr [9]. 2.3.4 Stphylococcus ureus count Bird Prker medium ws used for the enumertion of S. ureus. The specified dilutions were deposited on to the solidified medium nd spred over the surfce of the gr, the dishes were then inverted nd incuted t 37 C for 48±2 hr [10]. 2.3.5 Lctocilli count MRS medium ws used for the enumertion of lctocilli. The specified dilutions were deposited onto the solidified medium nd spred over the surfce of the gr, the dishes were then inverted nd incuted t 37 C for 48±2 hr [11]. 2.3.6 Yests nd moulds count Yest extrct gr medium ws used for the enumertion of yests nd moulds. The specified dilutions were deposited on to the solidified medium nd spred over the surfce of the gr, the dishes were then inverted nd incuted t 25 C for 5 dys [12]. 2.4 Sttisticl Anlysis Sttisticl Anlysis Systems (SAS, ver. 9) ws used to determine the effect of re nd processing steps on the microiologicl chrcteristics of cheese using Generl Liner Model (GLM) procedure. Duncn multiple rnge test ws used for seprtion of mens t P 0.05. 3. RESULTS Although there ws no significnt vrition (P>0.05) in the count of ll microes tested, the highest TVB nd yests nd moulds counts were found in Czgil re (Log 7.97 cfu/g nd Log 3.99 cfu/g, respectively), while slightly higher counts of coliform cteri (Log 7.67 cfu/g), S. ureus (Log 3.98 cfu/g) nd lctocilli count (Log 6.31 cfu/g) were reported in cheese from Rish re (Tle 1). TVBC nd S. ureus strted high (Log 7.97 nd Log 4.01 cfu/g, respectively) in the milk then slightly decresed in the cured efore, followed y n increse in the curd fter, then decresed in cheese delivered to the mrket. Coliform cteri count ws significntly (P<0.001) higher in rw milk, then stedily decresed in curd efore nd fter nd cheese delivered to the mrket. Lctocilli count stedily incresed from Log 5.29 cfu/g in milk to Log 6.33 cfu/g in cheese delivered to the mrket. Yests nd moulds count reched the highest count (Log 4.08 cfu/g) in curd fter, nd then decresed therefter to Log 3.95 cfu/g when cheese ws delivered to the mrket (Tle 2). In cheese from Rish re, only coliform cteri count significntly (P<0.001) decresed during processing nd delivery to the mrket, while other microorgnisms were not significntly (P>0.05) ffected. However, TVBC ws high in curd fter, while S. ureus count ws high in curd efore, nd the highest lctocilli count ws in cheese delivered to the mrket. The highest yests nd moulds count ws in curd efore (Tle 3). In Czgil re, coliform cteri count significntly (P<0.05) decresed from rw milk till cheese delivery to the mrket, while lctocilli nd yests nd moulds counts significntly (P<0.05) incresed. Although no significnt vrition ws found in TVBC nd S. ureus, the count of oth orgnisms decresed from rw milk till cheese delivery to the mrket (Tle 4). 3
Adll nd Omer; JAMB, 2(3): 1-7, 2017; Article no.jamb.33152 Tle 1. Microiologicl chrcteristics of cheese mnufctured in Rish nd Czgil Microorgnisms Are in which cheese ws mnufctured SE p Rish Czgil Totl vile cteri count 7.93 7.97 0.791 0.7644 Coliform cteri count 7.67 7.52 0.942 0.3952 Stphylococcus urous 3.98 3.83 0.461 0.4076 Lctocilli count 6.31 6.23 00755 0.2815 Yests nd moulds count 3.87 3.99 0.464 0.2009 Mens in the sme row ering similr superscripts re not significntly different (p>0.05) NS = Not significnt SL= Significnce level SE = Stndrd error of mens Tle 2. Microiologicl chrcteristics of rw milk nd cheese smples during processing till delivered to mrket Microorgnisms Milk efore fter Cheese delivered to mrket Totl vile cteri count 7.97 7.87 8.08 7.85 1.370 0.5869 Coliform cteri count 8.04 7.31 7.30 6.97 1.268 <0.0001 Stphylococcus ureus 4.01 3.95 3.99 3.58 0.685 0.1436 Lctocilli count 5.29 6.19 6.23 6.33 1.089 0.2616 Yests nd moulds count 3.51 4.03 4.08 3.95 0.692 0.0119 Mens in the sme row ering similr superscripts re not significntly different (p>0.05). *** = p<0.001 * = p<0.05 NS = Not significnt SL= Significnce level SE = Stndrd error of mens Tle 3. Microiologicl chrcteristics of milk curd efore nd fter nd cheese delivered to the mrket from Rish re SE P Microorgnisms Milk efore fter Cheese delivered to mrket Totl vile cteri count 1.864 7.68 7.83 8.17 7.91 Coliform cteri count 1.802 8.13 7.21 7.37 7.10 Stphylococcus ureus 0.982 3.99 4.09 4.08 3.60 Lctocilli count 1.439 5.46 5.91 6.05 6.36 Yests nd moulds count 0.950 3.51 5.97 4.02 3.83 Mens in the sme row ering similr superscripts re not significntly different (p>0.05). *** = p<0.001 NS = Not significnt SL= Significnce level SE = Stndrd error of mens SE p 0.4571 0.0004 0.5186 0.2756 0.3318 4
Adll nd Omer; JAMB, 2(3): 1-7, 2017; Article no.jamb.33152 Tle 4. Microiologicl chrcteristics of milk, curd efore nd fter nd cheese (Gin yd) delivered to the mrket from Czgil re Microorgnisms Milk efore fter Cheese delivered to mrket Totl vile cteri count 8.14 7.91 7.98 7.79 1.979 0.4701 c Coliform cteri count 7.93 7.39 7.22 6.77 1.772 0.0312 Stphylococcus ureus 4.03 3.74 3.87 3.55 0.931 0.5324 Lctocilli count 5.17 6.37 6.35 6.29 1.479 0.2508 Yests nd moulds count 3.51 4.08 4.12 4.04 0.997 0.3425 Mens in the sme row ering similr superscripts re not significntly different (p>0.05) * = p<0.05 NS = Not significnt SL= Significnce level SE = Stndrd error of mens SE P 4. DISCUSSION The results of microiologicl chrcteristics indicted tht TVB nd coliform cteri counts were higher in milk nd cheese indicting the unhygienic conditions under which milk ws produced nd cheese ws processed. All microgrms under investigtion were not significntly different in cheese produced in the two res which mens tht the processing conditions re somewht similr. Similr results were reported y Kmer nd Celik [13] for TBC, while lower vlues were reported y the sme uthors for coliform cteri count. The results re in disgreement with Ceyln et l. [14], nd in line with Aissi et l. [15]. S. ureus count exceeded Log 3.5 cfu/gm indicting tht cheese ws produced either from milk of mstitic cows or contmintion ccrued during processing. These results re not in line with Aissi et l. [15] who did not find ny colonies of S. ureus in locl cheese mrketed in Benin. However, the results of this study re in greement with Vurl et l. [16] who reported tht 84.76% of Orgu cheese smples were positive for Stphylococcus. Lctocilli count rnged etween Log 6.31 cfu/gm in Rish re nd Log 6.23 cfu/gm in Czgil re. The results of lctocilli count in this study re in ccordnce to the findings of Vurl et l. [16] who reported n verge of 3.4 10 6 cfu/gm of Lctocillus spp. in Orgu cheese. The results of yests nd moulds count were higher thn those reported y Menendez et l. [17], Mennne et l. [18] nd Vsek et l. [19]. Similr results were reported y Mennne et l. [20]. During processing to delivery to the mrket ll microorgnisms tested incresed fter then decresed in popultion when cheese ws delivered to the mrket. This might e due to unhygienic conditions which enled the cteri to grow, while the decrese in cheese delivered to the mrket might e due to the ntgonistic effect of slt nd lctic cid produced y nturl microflor. However, lctocilli count incresed in numer till delivery to the mrket. This might e ttriuted to the fvourle conditions for the nturl flor to proliferte nd increse in numer. The result of TVBC ws in greement with Efft et l. [21] who reported tht TVBC of ll functionl cheeses incresed during the first 10 dys of refrigertion period then declined reching the lowest count t the end. Cetinky nd Soyutemiz [22] reported tht during mnufcture of Kshr cheese, TVBC incresed from Log 6.5 cfu/gm in rw milk to s high s Log 8.0 cfu/gm in the cidified curd then decresed during het tretment of curd. Coliform cteri count followed the sme trend of TVBC. These results re in disgreement with Cetinky nd Soyutemiz [22] who reported pek coliform cteril count in the cogulum, followed y decline till het tretment of the curd. S. ureus count showed pek in rw milk nd curd fter, followed y decline in cheese delivered to the mrket. Lctocilli count showed n increse in rw milk till cheese delivery to the mrket. The results re in line with Sert et l. [23] nd Efft et l. [21]. Higher count of lctocilli could e ttriuted to the ility of the genus Lctocillus to survive t high cidity [21]. Cetinky nd Soyutemiz [22] reported tht lctic cid cteri on MRS gr medium stedily incresed to mximum during curd cidifiction nd then declined when curd ws het treted. Yests nd moulds count reched the mximum in curd fter then 5
Adll nd Omer; JAMB, 2(3): 1-7, 2017; Article no.jamb.33152 declined in cheese delivered to the mrket. Similr results re reported y Cetinky nd Soyutemiz [22] who reported tht yests nd moulds count reched the mximum in cidified curd followed y decline in het treted curd. 5. CONCLUSION The microil lod of cheese from two res ws not significntly different. Coliform cteri count ws significntly higher in curd efore nd fter, while yests nd moulds count ws high in curd fter, nd the rest of microes were not significntly ffected y the processing conditions. This investigtion highlighted the prolem of cheese mnufcture under trditionl conditions in Sudn which needs to e improved y legisltions nd lws tht govern this industry to produce sfe product to the consumer. COMPETING INTERESTS Authors hve declred tht no competing interests exist. REFERENCES 1. Adll OM, Dvidson PM. Effect of strter culture nd ntimicroils on the growth of Stphylococcus ureus in Gin Byd cheese. Institute of Food Technologists, Annul Meeting, Anheim Cliforni; 1990. 2. Adll OM, Christen GL, Dvidson PM. Chemicl composition of nd Listeri monocytogenes survivl in white pickled cheese. Journl of Food Protection. 1993;56(10):841-846. 3. Adll MO. Effect of processing conditions on the microiologicl qulity of white pickled cheese. Ph.D. Disserttion, University of Tennessee, Knoxville, U.S.A; 1993. 4. Irhim AA. Effect of processing nd storge conditions on the chemicl composition nd microil qulity of white soft cheese. M.Sc. Thesis, University of Khrtoum, Sudn; 2003. 5. Bintsis T, Ppdems P. Microiologicl qulity of white-rined cheeses: A review. Interntionl Journl of Diry Technology. 2002;55(3):113-120. 6. Vidojevic AT, Vuksinovic M, Veljovic K, Ostojic M, Topisirovic L. Chrcteriztion of microflor in homemde semi-hrd white Zltr cheese. Interntionl Journl of Food Microiology. 2007;114:36 42. 7. Suliemn EA, Mustf AW, Adelgdir SW, Elkhlif AE. Impct of comintion of lctic cid cteri nd yests in fermenttion of Jin- eid. Journl of Microiology Reserch. 2013;3(3):124-129. 8. Houghty AG, Mturin LJ, Koenig KE. Microiologicl count methods. In: stndrd methods of the exmintion of diry products. 16 th edition. Mrshl RT, (edt.). Wshington, D.C.: Americn Pulic Helth Assocition, USA. 1992;213-246. 9. Christen LG, Dvidson PM, McAllister JS, Roth LA. Coliform nd other indictor cteri. In: Stndrd Methods of the Exmintion of Diry Products. 16 th edition. Mrshl RT, (edt.). Wshington, D.C.: Americn Pulic Helth Assocition, USA. 1992;247-269. 10. Flowers SR, Andrews W, Donnelly CW, Koenig EK. Pthogens in milk nd milk products. In: Mrshl, R.T., (Ed.), Stndrd Methods for the Exmintion of Diry Products. 16th Edn., Americn Pulic Helth Assocition, Wshington, DC, USA. 1992;103-212. 11. Hrrign WF, McCne ME. Lortory methods in food nd diry microiology. London, UK: Acdemic Press; 1976. 12. Frnk FJ, Christen LG, Bullermn LB. Tests for groups of microorgnisms. In: Stndrd methods for the exmintion of diry products. 16 th edition. Mrshl RT, (edt.). Wshington, D.C.: Americn Pulic Helth Assocition, USA. 1992;271-286. 13. Kmer U, Celik HT. Some microiologicl nd chemicl chrcteristics of Gorcol cheese. YYU Vet. Fk. Derg. 2006; 18(1):87-92. 14. Ceyln ZG, Turkoglu H, Dyisoylu KS. The microiologicl nd chemicl qulity of Skim cheese produced in Turkey. Pkistn Journl of Nutrition. 2003;2(2):95-97. 15. Aissi VM, Soumnou MM, Bnkole H, Toukourou F, de Souz AC. Evlution of hygienic nd mycologicl qulity of locl cheese mrketed in Benin. Austrlin Journl of Bsic nd Applied Sciences. 2009;3(3):2394-2404. 16. Vurl A, Erkn EM, Gurn SH. The exmintion of the microiologic qulity in Orgu cheese (rided cheese) smples. Kfks Univ. Vet. Fk. Derg. 2010;16 (Suppl-A):S53-S58. 17. Menendez S, Godinez R, Centeno JA, Rodriguez-Otero JL. Microiologicl, 6
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