manufacture of Camembert cheese specialty Ladhidh

precookingUHT treatmentcoolingcreamingpackagingAddition of ingredients- Water- Powders- Materials- Melting saltsMaterials and methods28- Recirculation (1500 rev / min) ;- Chambering (60 seconds) ;- Injection of cold 90 ° C ( second quantity of water) water ;- Recirculation (1500 rev / min for 30 seconds) .Subsequently , the pulp passes through the creaming to 1500 rev / min for 60 seconds andFinally the cheese is packed in 90 g portions of rectangular ( Figure II -2 ) .Figure II-2 . Main stages of manufacture of Camembert cheese specialty Ladhidh4. Collecting and sampling4.1 . MetijaThe sample is taken from four points of the manufacturing process in threesterile vials for each sample ; at the mixer , after precooking ,two samples after UHT treatment and after packaging into the caster .4.2 . Ladhidh CamembertFor Ladhidh Camembert , the samples were taken in the same way butonly three levels of manufacturing ; after grinding, after cooking and the conditioner .Sterile vials are stored thereafter in a refrigerator at a temperature of4 ° C until analysis.Preparation of FormulagrindingbakingpackagingAddition of ingredients- Water- Powders- Materials- Melting saltsMaterials and methods295 physicochemical analyzes .5.1 . PH measurementPH measurements are made with a pH meter (Model 9450 , Unicam , Cambridge,UK) directly introducing the two probes ( temperature and pH ) in a sample of thecheese mass at a temperature of 20-25 ° C. Measurements were made ​​in triplicate.5.2 . Measuring the fat contentThe fat is determined by the Gerber method or methodacidobutyrometrique VAN GULIK ( ISO: 3433-2002 ) .• PrincipleFat cheese is separated by centrifugation butyromètre aftercheese proteins dissolved by sulfuric acid . The separation of the fat ispromoted by the addition of a small quantity of isoamyl alcohol . The fatis obtained by direct reading on the scale of butyromètre .• ProcedureIn a glass container previously weighed 4 g of sample is introducedcheese . The cup is inserted into the belly of butyromètre and fixed cap neck . wesulfuric added by the opening of the rod until the acid level of the acid exceedscup about 2 mm.After having plugged the opening of the rod , the butyrometer is placed in a water bath65 ° C. Stirring occasionally butyrometer in a horizontal plane until dissolvedcomplete the test sample .1 ml of isoamyl alcohol was added , then sulfuric acid to 35 ml traitof the graduation . The butyromètre is stirred vigorously in a vortex mixer to make thehomogeneous liquid and then placed in the water bath for 5 min .Was centrifuged for 10 minutes and placed back in the butyrometer waterbathfor 5 min . The fat is obtained by direct reading on the scale ofbutyromètre and measurements are performed in triplicate .Materials and methods305.3 . Measurement of dry matterThe determination of the dry extract is performed by a dryer SARTORIW -M150 , itsprinciple is based on the elimination of water at a temperature of 103 ± 2 ° C untilconstant weight of the analyzed specimen.A test sample of 3 g was spread over the entire surface of an aluminum cappreviously weighed and introduced into the dryer and the analysis is started. The value ofthe solids percentage (%) is read directly from the digital display after the beepsound . The measurements are performed in triplicate.5.3.1 . Determination of the solids by the method of Reference• PrincipleThis method is based on the evaporation of water from a test sample , in the presence ofsand ( quartz sand or sea sand washed acid particle size > 150 microns and < 600 microns )in an oven at a temperature of 102 ± 2 ° C to constant weight ( ISO: 5534-2004 ) .• Procedure Blank testParallel with the determination of the sample , perform a blank test under thesame procedure as for the preparation of the capsule but without determining thetest sample . Preparation of the dishPlace the dish containing about 20 g of sand, stick and lid in the ovenfor at least 1 hour , when the oven has reached the required temperature.Put the lid closed cool in the desiccator until capsuleambient temperature and weigh all the nearest 1 mg , recording the mass with 4 decimal places. Taking Test- Drag the sand on one side tilting of prepared dish .- Claim approximately 3 g of the sample on a surface of the sand-free capsule .- Replace the lid, there have baguette and weigh to the nearest 1 mg , recording the mass4 decimal places.Materials and methods31 Determination- Thoroughly mix the sample set and the sand and spread regularlymixture on the bottom of the capsule .- Leave the flattened wand into the mix ends.- Place the dish in an oven with the cover below for 3 hours ( oncerequired temperature is reached) .- Put the lid , allow to cool in the desiccator the closed capsule toambient temperature and weigh to the nearest 1 mg , recording the mass to 4 decimal places.- Put back in the oven for 1 hour ( once the required temperature isreached).- Put the lid and allow to cool in a desiccator as before.- Weigh to the nearest 1 mg , recording the mass to 4 decimal places.- Repeat placed in an oven for 1 hour to observe, between two successive weighingsa decrease in mass ≤ 2 mg or an increase in mass . Note the mass mostweak.• Expression of resultsThe percentage by weight dry matter , is calculated using the formulafollowing :MS = [( m2 - m0 ) - ( m3 - m4) / (m1 - m0 ) ] x 100where:MS: dry matter.m0 : is the weight , in grams , of the capsule ( including sand ) , and the lidwand.m1: is the mass , in grams , of the capsule ( including sand ) , the cover of therod and the sample .m2: is the weight in grams of the capsule ( including sand ) , the cover of thebaguette and dry test sample .m3 is the mass in grams of the capsule used for the blank test for the samedrying time than m2 .M4: is the mass in grams of the prepared capsule used for the blank .Express the result in g / 100 g to 2 decimal places .Materials and methods325.4 . Determination of ashThe ash content is determined according to the method described by AOAC (2002) bycalcining a test 5 g of cheese specialty taken in a crucible at atemperature of 550 ° C in a muffle furnace " LINN HightTherm " for 4 hours , theFollowing the ash contained in the crucibles were transferred to a desiccator and weighedby a precision balance .The ash content is determined by the following formula :Ash content ( % ) = ( Mf - M0 / 5 ) x 100Where Mf : empty weight of the crucible plus that of the sample, M0: unladen mass of the crucible.Determination of ash is performed in triplicate .5.5 . Determination of protein contentThe determination of the nitrogenous matter is performed according to the Kjeldahl method (AOAC ,1997) .This method of reference is based on the transformation of organic nitrogen into nitrogenmineral form of ammonia ( NH4) 2SO4 by the oxidative action of boiling sulfuric acidthe organic material in the presence of a catalyst of mineralization ( Na2SO4 17 g/100 g ;CuSO4 5H2O 1.5 g/100 g).The samples were introduced into the flask ( digestion tubes ) , thenore on a ramp ( Kjeldatherm , Gerhardt, The King Essarts , France ) at 420 ° C for3 h . Ammonium sulfate ( NH4 ) 2SO4 is the essential product of the mineralization , obtained byadding 0.01 N sulfuric (H2SO4) acid . A strong base (NaOH ) is added in equal volume toH2SO4 volume introduced .( NH4) 2SO4 + 2 NaOH Na2SO4 + 2 H2O + 2 NH3During the distillation , the formed ammonium hydroxide (NH4OH ) is driven by thesteam and recovered in a titration vessel containing a solution of boric acid in excess.The formed ammonium borate ( ( NH4 ) 3BO3 ) increases the pH of the solution . The solution isthen titrated with sulfuric acid under . The volume of sulfuric acid is addedthe ammonium content in the sample of departure. The assay is performed automaticallyMaterials and methods33with a device type Vapodest 50 Gerhardt . For each sample , the analysis is repeatedthree times .The results are expressed in g per 100 g of cheese according to the following formulas andFinal results are expressed as a percentage of total nitrogen ( % NT ) .NT = ( V1 - V0) x 0.14 x 10 / PProtein levels (g/100 g cheese) = 6.38 x NTWith V1 : H2SO4 volume required for titration of the sample in ml ;V0 : volume of H2SO4 required for titration of the blank in ml ;P : mass of sample in g cheese ;6.38 : Protein factor ( Adler - Nissen , 1986).5.6 . Dosage rate chloridesThe sodium chloride content is determined by a potentiometric methodusing a chloruromètre ( Subra -S100 Grosseron , St. Herblain , France). A test sample of10 g of cheese , accurately weighed , are added 90 ml of distilled water . The assembly ishomogenized in a mortar . The unit is turned on 20 minutes before measurement. theswitch is set to 100 mu.l . A volume of 15 ml solution " for chloruromètre "according to the formula of the manufacturer, are introduced into a beaker. After having put in place the beaker ,the " C " button (conditioning ) is actuated , in order to remove traces of NaCl in the solution .A fixed value is displayed. A volume of 1 ml of gl- 1of NaCl was added and the"T" button ( titration) is actuated. Still in the container containing the calibration solution , 1ml of the aqueous suspension of cheese is introduced , followed by titration . The results areexpressed in g (NaCl ) of 1 - kg cheese ( DFI 88A : 1988 ) . .5.7. Microscopic observation of starch5.7.1 . Morphological observation of starch grains (E 1422 )The observation of cross-linked starch grains ( hydroxypropyl distarch phosphate E1422 ) is formed by an optical microscope under a magnification of objective ( 100 x G ) inamount a pinch of starch powder with a drop of cedar oil for claritymicroscopic between slide and coverslip and ( DALLY et al. , 2007).Materials and methods345.7.2 . Morphological observation of the starch grains in the specialty cheeseFew mg of specialty cheese are perfectly spread on a slide with adrop of cedar oil and a coverslip is placed . The sample is observed under a microscopeoptical lens with a magnification (G x 100).Photos are taken on observations using a digital camera to a3 Mega pixel resolution .5.8. Viscosity MeasurementThe viscosity was determined by a Brabender Viscometer MESSTECHNIKintegrated in the creamer to a level of 380 kg of cheese paste and at a temperature of 83 ° CMetija for cheese specialty , and a scraper speed of 7 rev / min , a level of 14 cmand a temperature of 73 ± 1 ° C for Ladhidh Camembert every 5 minutes.5.9 . Flow MeasurementThe determination of the flow is carried out by the OLSON and PRICE ( 1958) methodamended by MOUNSEY and O'Riordan ( 1999).A tube of 2 cm internal diameter and 20 cm long is all graduated in cm 2lengthwise and closed by rubber plugs at both ends. Seventeengrams of cheese specialty are first placed in the tube and packed upoccupy a volume corresponding to a distance in the tube of 5.5 cm length. This tube isplaced horizontally in a water bath at a temperature of 82 ° C for 9.5 minutes. thetube is then removed from the water bath and the distance from the reference lineis measured in mm after 1 minute at an ambient temperature as an indicator offlow .5.10 . statistical AnalysesThe results were treated using XLSTAT a statistical software (2008 ) . analysisof variance (ANOVA ) was performed to determine the significance of changes inphysicochemical parameters during the manufacturing process ( the level of significance wasset at 0.05 ) .Materials and methods35Bacteriological 6 . AnalysesIn this study, we limited ourselves to verify the presence orthe absence of indicators of hygiene germs , including settlementshealth . According Tesone and Quevedo (1978) , the seeds of particular importancecan cause food-borne infections are total coliforms , coliformscoliforms, staphylococci and anaerobic spores gasifiers (SAG) .6.1 . Coliform and / or presumptive coliforms6.1.1 . recallColiforms are included in the family Enterobacteriaceae but belong todifferent genres such as Citrobacter , Klebsiella, Escherichia and Enterobacter . These areGram (-) negative oxidase.6.1.2 . principleCount typical colonies of total coliform that developed24 h at 30 ° C and fecal coliform bacteria grow in 24 h at 44 ° C on agar VRBL thenconfirmation of the number of colonies from lactose . This is an enumeration ofcoliforms ( NF ISO 4832 ) .6.1.3 . Culture mediaThe culture medium is an agar biliée lactose crystal violet and neutral red( VRBL ) with a pH = 7.4 ± 0.2 at 25 ° C , its composition is given in Table II-1 .Table II- 1. Composition of the lactose agar biliée crystal violet and neutral red( VRBL )- Enzymatic digest of animal tissue ( Peptone ) ......................................... ....... 7.0 g- Extract levure....................................................................................................... 3.0 g- Lactose .................................................................................................................... 10.0 g- Bile salts ............................................................................................................ 1.5 g- Sodium chloride .............................................. .................................................. . 5.0 g- Red neutre............................................................................................................ 30.0 mg- Crystal Violet ............................................................................................................ 2.0 mg- Agar-agar................................................................................................................. From 12 to 18 gMaterials and methods36- Water .......................................................................................................................... 1000 ml6.1.4 . Confirmation mediumThe middle confirmation is lactose bile broth brilliant green ( BGBB ) with apH = 7.2 ± 0.2 at 25 ° C , its composition is given in Table II-2 .Table II -2. Composition of lactose bile broth brilliant green ( BGBB )- Enzymatic digest of casein ( Tryptone ) .......................................... ................. 10.0 g- Lactose .................................................................................................................... 10.0 g- Bile dried beef ............................................. .......................................... 20.0 g- Bright Green ............................................................................................................. 0.0133 g- Water .......................................................................................................................... 1000 ml6.1.5 . procedure- Inoculated in a sterile Petri dish , 1 ml of the sample or primary dilution ;- Start with the first decimal dilution , then with subsequent dilution ;- Pour agar supercooled in each petri dish ;- Mix well all by rotation and allow to solidify ;- Now make a double layer of VRBL middle surface of the inoculated medium ;- Incubate at 30 ° C ± 1 ° C for 24 ± 2 h .6.1.6 . Selection and colony countTypical colonies of coliforms are purple with a diameter of 0.5 mmor more , sometimes surrounded by a reddish area due to the precipitation of bile. the resultsare expressed as the number of coliforms / ml of the product.6.2 . Enumeration of staphylococci6.2.1 . principleFrom the sample ( liquid product ) or the stock solution ( other products) , weperforms decimal dilutions and , in parallel , the surface of seeded agar Baird Parkerprecast in Petri dishes with each dilution retained (ISO 6888-1 ) .After incubation for 48 hours at 37 ° C , colonies characteristics and / or nonappeared characteristics are counted.Materials and methods376.2.2 . Culture mediumThe culture medium is a Baird Parker agar precast with pH 7.2 ± 0.225 ° C , the composition is given in Table II -3 .Table II-3 . Baird Parker medium composition precast- Tryptone........................................................................................................................ 9.47 g- Meat extract .......................................................................................................... 4.74 g- Autolytic yeast extract ............................................. ............................................ 0.95 g- Sodium pyruvate ...................................................................................................... 9.47 g- Glycine ......................................................................................................................... 11.37 g- Chloride lithium....................................................................................................... 4.74 g- Agar agar bactériologique............................................................................................. 14.21 g- Plasma rabbit EDTA................................................................................................. 25.0 ml- Bovine fibrinogen ........................................................................................................ 5.0 g- Inhibitor trypsine.................................................................................................... 25.0 mg- Tellurite potassium................................................................................................... 25.0 mg- Eau…………………………………………………………………………………….. 1000 ml6.2.3 . procedure- Dry agar plates in an oven at 46 ° C ± 1 ° C until complete disappearancedroplets to the medium surface ( lid removed and the agar surface facingbelow).- Mix each dilution before inoculation on the surface of agar plates andbefore performing decimal dilutions .- Remove 0.1 ml of the suspension and / or decimal dilutions selected , theagar surface by changing pipette each dilution .- Spread the inoculum thoroughly as soon as possible without touching the edgesbox .- Leave the boxes, lid closed, for 15 minutes at room temperature.- Incubate in an oven for 48 hours ± 2 hours at 37 ° C ± 1 ° C.Materials and methods386.2.4 . countingBoxes containing less than 150 colonies characteristics and / or non-characteristicat two successive dilutions are retained ; but one of them must contain atleast 15 colonies. Characteristics and / or non-characteristic colonies are countedmanually .Typical colonies after 48h ± 2h incubation are black or gray , shinyconvex and whose diameter is at least 1 mm and at most 2.5 mm surrounded by aclarification halo and precipitation .The non-characteristic colonies after 48h ± 2h incubation are black and shinywith or without a white border with narrow clarification halos and precipitation absent orbarely visible. They can be gray without clear zone .6.3 . Anaerobic spore count gasifiers (SAG) : number technique moreprobable NPP6.3.1 . principleSeeding 3 tubes per dilution decimal this to 3 decimal dilutionssuccessive , a nonselective semisolid medium RCM (Reinforced Clostridial Medium) ofHirsch and Grinsted , adding an agar plug for the anaerobic conditions. implementationDemonstration of the production of gas and obtaining a coefficient calculation NPP by the number ofpositive tubes and comparison with MPN table. The results are expressed as the number ofanaerobic spores gasifiers per gram of product .6.3.2 . Culture media and reagents• Bouillon RCM Hirsch and GrinstedTable II -4 shows the composition in grams per 1 liter of medium broth RCMHirsch and Grinsted ( 38 g / l ) .Materials and methods39Table II-4 . Composition in grams per 1 liter of medium broth and RCM HirschGrinsted ( 38 g / l )- Tryptone.............................................................................................................................. 10- Extract viande.................................................................................................................. 10- ............................................. Enzyme Yeast extract ................................................. 3- Cysteine ​​( hydrochloride ) ........................................................................................................ 0.5- Sodium chloride (NaCl ) ........................................... .................................................. 5 ....- Glucose ................................................................................................................................ 5- Starch soluble.................................................................................................................... 1- Sodium Acetate ............................................................................................................... 3- Agar agar bacteriological .............................................. .................................................. 0.5 ...• RCM Agar Hirsch and GrinstedTable II -5 , gives the composition in grams per liter of medium 1 agar RCMHirsch and Grinsted ( 52.5 g / l )Table II -5. Composition in grams per 1 liter of agar RCM Hirsch and Grinsted- Tryptone .............................................................................................................................. 10- Meat extract ................................................................................................................. 10- ............................................. Enzyme Yeast extract ................................................. 3- Cysteine ​​( hydrochloride ) ........................................................................................................ 0.5- Sodium chloride (NaCl ) ........................................... .................................................. 5 ....- Glucose ................................................................................................................................ 5- Starch soluble.................................................................................................................... 1- Sodium Acetate ............................................................................................................... 3- Agar agar bacteriological .............................................. .................................................. 15 ...• RCM semi- solid mediumComplete medium was obtained by using for preparation of a semi liter of medium