Chemical examination Chemical examination ofofmeat & meat productmeat & meat product

Chemical examination ofChemical examination ofmeat & meat productmeat & meat product

Dr. / Fahim ShaltoutDr. / Fahim Shaltout Professor of Meat HygieneProfessor of Meat Hygiene Food Control DepartmentFood Control Department Faculty of Veterinary MedicineFaculty of Veterinary Medicine Benha University, Egypt.Benha University, Egypt. Email: Email: fahimshaltout@hotmail.comfahimshaltout@hotmail.com

list of most chemical list of most chemical teststests

11 - -detection of Ab residuesdetection of Ab residues . .

22 - -Estimation of moisture contentEstimation of moisture content . .

33 - -Estimation of fat contentEstimation of fat content . .

44 - -Estimation of protein contentEstimation of protein content . .

55 - -Estimation of free fatty acidsEstimation of free fatty acids . .

66 - -Estimation of pig fat (Lard)Estimation of pig fat (Lard)

77 - -Detection of animal speciesDetection of animal species . .

88 - -Detection of addition of chemical Detection of addition of chemical preservatives preservatives

11 - -Detection of Ab residueDetection of Ab residue in meat & meat in meat & meat productproduct..

The principle of this test consist of anThe principle of this test consist of an

Inhibition of growth of an Ab-sensitiveInhibition of growth of an Ab-sensitive

Test strain by inhibitory substance inTest strain by inhibitory substance in

The sampleThe sample . .

This detected by formation of anThis detected by formation of an

Inhibitory zoneInhibitory zone . .

TeTest strain used is B. subtilis.st strain used is B. subtilis. - we perform the test in acid & - we perform the test in acid & alkaline medium at pH 6 & 8 alkaline medium at pH 6 & 8 as some Ab have greater effect as some Ab have greater effect at lowered pH as tetracycline , at lowered pH as tetracycline , tylosin & erythromycin . tylosin & erythromycin . An inhibition zone around the An inhibition zone around the sample of 2mm or more is positive sample of 2mm or more is positive less than 1mm is negative & less than 1mm is negative & 1-2mm is doubtful result 1-2mm is doubtful result. .

There are number of method used inThere are number of method used in Determination of moisture contentDetermination of moisture content . .

There are 2 official methodsThere are 2 official methods : : 11 - -Drying to constant weight at 95-100Drying to constant weight at 95-100

Under pressure not exceed 100 mmHgUnder pressure not exceed 100 mmHg22 - -Drying over H2so4 in vacuum desiccatorDrying over H2so4 in vacuum desiccator

At a pressure not more than 10mm Hg toAt a pressure not more than 10mm Hg to A constant weightA constant weight . .

Determination of moisture content.

Estimation of fat Estimation of fat contentcontent. .

This done by soxhelt methodThis done by soxhelt method . .

By extraction of meat fat by using of fatBy extraction of meat fat by using of fat

Solvent as etherSolvent as ether . .

Then calculate fat percentThen calculate fat percent . .

Estimation of protein Estimation of protein contentcontent. .

By using Kyldehal methodBy using Kyldehal method

Estimation of free F.AsEstimation of free F.As

As free F.As indicate rancidityAs free F.As indicate rancidity . . Thiobarbituric acid testThiobarbituric acid test

Saponification numberSaponification number Reichert meissel numberReichert meissel number . .

Detection of lardDetection of lard . .

By making some tests asBy making some tests as : :

11 - -specific gravityspecific gravity . .

22 - -melting point ( 42-48 )melting point ( 42-48 ) . .

33 - -Refractive indexRefractive index . .

44 - -Iodine value ( 51-70 )Iodine value ( 51-70 ) . .

55 - -Saponification numberSaponification number . .

66 - -Reichert meissel numberReichert meissel number . .

Detection of animal Detection of animal speciesspecies

By using precipitation testBy using precipitation test . . It is biological method for differentiationIt is biological method for differentiation

Between meat of different speciesBetween meat of different species . . It's idea based upon that if foreign proteinIt's idea based upon that if foreign protein

))AgAg ( (injected into rabbit , specific Ab will be injected into rabbit , specific Ab will be formed against the injected proteinformed against the injected protein . .

This test is applied by using un known This test is applied by using un known diluted Ag (meat extract) against knowndiluted Ag (meat extract) against known

Un diluted Ab (serum containing Ab)Un diluted Ab (serum containing Ab)..

Valuable for identification of fresh , frozen & pickled meat.In smoked meat or cooked test is useful provided that

Temperature in the center not exceed 70 otherwise Coagulated & result will be doubtful

But confusion occur in case of meat which are Close to each other as (Horse- donkey)

)Sheep – goat(

N.B

Detection of chemical Detection of chemical preservatives preservatives

As some chemical which added to meatAs some chemical which added to meat

To increase shelf life time which may beTo increase shelf life time which may be

Harmful to humanHarmful to human . .

AsAs : :

Sulfite , Nitrate , Nitrite , Nacl , StarchSulfite , Nitrate , Nitrite , Nacl , Starch

Detection of Addition of Detection of Addition of water water

By using of Feder's numberBy using of Feder's number. .

--Not more than 4 in minced meat Not more than 4 in minced meat from cattlefrom cattle

--Or 4.5 in minced meat from porkOr 4.5 in minced meat from pork

Detection of Horse meatDetection of Horse meat. .

By using ofBy using of: :

11 - -Sulphoric acid testSulphoric acid test..

22 - -Ehrlich testEhrlich test. .

33 - -Glycogen testGlycogen test. .

Thank youThank you