Meat hygiene lecture 3Meat hygiene lecture 3

Animal bleedingAnimal bleeding-:-: The purpose of bleeding: - to get rid from the large amount of blood in circulation The purpose of bleeding: - to get rid from the large amount of blood in circulation

system vastly it's remain in the body provide a good medium for M.O. thatsystem vastly it's remain in the body provide a good medium for M.O. that ’’s why the s why the remain blood will effect on flesh or meat qualityremain blood will effect on flesh or meat quality..

The bleeding process will excreta 1/2 - 2/3 of body blood, the other blood remain in The bleeding process will excreta 1/2 - 2/3 of body blood, the other blood remain in tissues, organ and visceraltissues, organ and visceral..

Factors effecting on bleedingFactors effecting on bleeding-:-:

The bleeding effect by body weight, sex, age, bread physiological conditionThe bleeding effect by body weight, sex, age, bread physiological condition..

The remain blood is very large in tired, feverish animal the bleeding process must be The remain blood is very large in tired, feverish animal the bleeding process must be continue for 5-10mincontinue for 5-10min

Meat markingMeat marking

The purpose for meat marking is threefold it's indicates that's the carcass has been The purpose for meat marking is threefold it's indicates that's the carcass has been inspected or judge or both and is there fore a guarantee the consumer, it will prevent the inspected or judge or both and is there fore a guarantee the consumer, it will prevent the substation of sound organs for diseased onesubstation of sound organs for diseased one..

And its forms a ready means of identification of meat about which question may And its forms a ready means of identification of meat about which question may subsequently arisesubsequently arise..

And may be it done in several waysAnd may be it done in several ways:: Use of stamp, branding, tags or labelsUse of stamp, branding, tags or labels..

The best and most convenient method is by the use of a metal stamp (single or ruler)The best and most convenient method is by the use of a metal stamp (single or ruler)..

The stamping ink must be harmless, adherent quick drying and readily visible, and a (1-The stamping ink must be harmless, adherent quick drying and readily visible, and a (1-2%) of fuchsine solution fulfils all these requirement in many countries carcasses are 2%) of fuchsine solution fulfils all these requirement in many countries carcasses are graded according to the qualitygraded according to the quality..

The carcass has been marked on the thigh in case of single stamp but in case of ruler The carcass has been marked on the thigh in case of single stamp but in case of ruler stamp the carcass marked but along of spinal cordstamp the carcass marked but along of spinal cord..

The most two important phenomenon affects The most two important phenomenon affects on meat areon meat are::

11 - -Rigor motrisRigor motris..

22--Hydrogen ion concentration of musclesHydrogen ion concentration of muscles-:-:

Meat from freshly killed cattle has an average Meat from freshly killed cattle has an average pH. of 6.5 to 6.8 and some times. Up to 7.2 but pH. of 6.5 to 6.8 and some times. Up to 7.2 but the pH then falls rapidly, reaching its lowest level the pH then falls rapidly, reaching its lowest level of 5.6 to 5.8 within 48hrs after slaughterof 5.6 to 5.8 within 48hrs after slaughter..

. The pH then remains constant for some times this period depending on whether the carcass has been probably cooled and also on the degree of bacterial contamination & the storage condition subsequently the pH begins

to rise slowly due to-:

A- Autolysis

B- Bacterial growth.

When pH of 6.4 is reached, there is suspicion of the presence of decomposition, while when muscle reaches a pH 6.8 or over, the objective signs of decomposing become apparent in the meat as change in odor, color, and texture.

The period of pH decreasing and ↑ is different from animal to other in normal animal the decreasing is occur gradually tell it's reach the lowest degree and when it's a rise that's will be gradually too.

I febrile exhausted and stunning animal at the time of slaughter ↓ in pH of muscles are suddenly of rapidly. The increasing is rapidly of suddenly too because the glycogen in these animals are turned to lactic acid through the art

slaughter period.

In another side when the meat keep at freezing degree, the pH remain stable but when the meat is melted the pH will a rise rapidly which allow the

microbial growth .

Estimation of the pH of meat is of values in the judgment of border-line cases. Particularly of emergency-slaughtered animal for it provides an indication as to whether or not the meat will posses adequate durability.

The important cases which pH is The important cases which pH is measuredmeasured::

11 - -Emergency slaughterEmergency slaughter..

22 - -To estimate the bleeding degree of carcassTo estimate the bleeding degree of carcass . .

33 - -In microbial examination of carcassIn microbial examination of carcass..

The importance of meat pHThe importance of meat pH

11 - -Great importance in meat preservationGreat importance in meat preservation..

22 - -The acidic medium is lead to M.O The acidic medium is lead to M.O destructiondestruction . .

33 - -The acidic medium lead to meat The acidic medium lead to meat ripeningripening..

Common cases in Common cases in slaughterhouseslaughterhouseA-Physiological cases judgment:-A-Physiological cases judgment:-

- - Flesh of fetuses & still born animals:-Flesh of fetuses & still born animals:-

It's doubtful whether consumption of the flesh of It's doubtful whether consumption of the flesh of unborn or stillborn calves could be prejudicial to health, unborn or stillborn calves could be prejudicial to health, but the sale of such flesh is unjustifiable for the following but the sale of such flesh is unjustifiable for the following reason:-reason:-

1- Consumption of the flesh of unborn animals is 1- Consumption of the flesh of unborn animals is repugnant to most of the civilized races.repugnant to most of the civilized races. 2- The commonest cause of dairy cows giving birth to 2- The commonest cause of dairy cows giving birth to stillborn calves is infecting with stillborn calves is infecting with Brucella abortus Brucella abortus the the infective M.O. being present in large amount in infective M.O. being present in large amount in aborted calves.aborted calves.

3- Proportion of cows suffering from tuberculosis metritis 3- Proportion of cows suffering from tuberculosis metritis may give birth to stillborn calves which likely to be may give birth to stillborn calves which likely to be affected with congenital T.B. affected with congenital T.B.

Signs- :

1 -The skin presents a sodden appearance .

2 -The claws are soft & yellowish & the pads of the sole convex, a condition usually referred to as the (golden shipper) .

3 -The remain of umbilical cord can be seen attached to open umbilical ring, while the umbilical arteries & veins are present & contain

liquid blood .

4 -The stomach & intestine are free of coagulated milk, & the lungs are collapsed & sink in water.

5 -At dressing. The hoofs, intestinal tract & umbilical.

6 -The muscles are loose & flabby .

2 -Immaturity-: The only food animal which is likely to be slaughter & exposed for

sale while in an immature condition is the calf .

1 -In newly born calf, the hoofs are soft & have conical processes on their solar surface.

2 -At birth calves are usually born with eight the last pair will erupt in 2 days.

3 -The umbilical cord dry & black in 4 to 5 day. & falls off from the umbilical between the 8th & 16th day to leave sensitive surface which is soon covered by a scab.

4 -Ictric discoloration of the kidneys is of almost regular occurrence in calves up to 14 days old the renal cortex assuming a dark-olive or olive-green color because of a heavy deposit of bile pigment, though

the renal medulla is unchanged .

Judgment-:

The consumption of the flesh of newborn or very young animal though admittedly not prejudicial to health, but it's repugnant to the vast majority purchasers.

Because of luck of fat with high concentration of water in muscles (water soaked) a reach about 76% that's mean the consumer buy water +

bone only .

3 -Advanced pregnancy:

According to vet legislation it's not allowed to slaughter female unless if it's sterile or un response to the treatment, or expose to accident.

Judgment:

The female flesh fit for human consumption if the fetus was alive at slaughtering & there is no acetonemia but it's rejected if the fetus was dead & there is metritis or mummy fetus.

4 -Poorness or leanness-:

It's a physiological condition caused by an intake of inadequate nutrient for the animals normal requirements. And it's seen in young growing animals, in cows which are milking heavily. it's characterized by sparse development of fatty tissue but certain amount remains in particular location such fat that is present on the carcass is of normal appearance and composition, and the muscular tissue is firm though darker than normal.

Judgment:

The physiological leanness is of no significance in meat inspection, but the meat is that due to an increased development of connective tissue in the muscle. The rigor mortis is good but meat considered as second

degree .

5 -Abnormal odors and tastes-:

The cause of abnormal odors & tastes :

A : out side sources :- (external)

1 -Consumption of certain food stuffs, like garlic, onion, cauliflower, or feeding chickens on fish diet.

2 -From drugs administrated as medicine. like turpentine, Iodine, phenol ether, DDT .

3 -Absorption of the odors of strong smelling substance whilst the meat is stored Like oranges, apple or citrus food during the sea shipping .

B: In side sources (internal):

1 -Sexual odors: in meat animal especially goats this is caused by a steroid substances, androstenone it's appear in flesh and fat of the

carcass .

2 -Product's of abnormal metabolism:- Like acetone odor or apple odor in cows with acetonaemia, milk fever, fever

3 -Pathological reasons: like Uremia, Pyemia gangrene, black leg,

we smell an odor of rancid butter or chess in muscles area .

Abnormal odors and particularly the male sexual odors Abnormal odors and particularly the male sexual odors

are most appear ant immediately after slaughter and are most appear ant immediately after slaughter and before the meat and fat have cooled, these odors may before the meat and fat have cooled, these odors may disappear after cooling but reappear when the meat is disappear after cooling but reappear when the meat is cooked ,That's why the tests of abnormal odor should be cooked ,That's why the tests of abnormal odor should be done like, boiling, frying & roasting testdone like, boiling, frying & roasting test . .

JudgmentJudgment-:-:

In case of very strong odors & the cause are In case of very strong odors & the cause are pathological or drugs the whole carcass be rejectedpathological or drugs the whole carcass be rejected . .

But if the odor relative low and no pathological But if the odor relative low and no pathological causative the carcass is passing as a second degreecausative the carcass is passing as a second degree . .