FACTORS CAUSING UNDESIRABLE MEAT FLAVORS

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FACTORS CAUSING U k O E S I R A B L E N E A T F l A V O R S

D A V I D L. MACKINTOSH K A N S A S S T A T E C O L L E G E

Flavor i s generally thought of a8 that quali ty of anything tha t a f f ec t s the taste; flavor nay be grat i fying o r it m y be obJectionable. is generally accepted that there are only four primary t a s t e qual i t ies ; sweet, acid, salty, and bitter. specif ic taste buds i n the tongue and throat for each o f these t a s t e quali- t i e s , though there i e no supporting histological evidence f o r this theory. Volumes have been writ ten on taste but probably the most recent and most com- prehensive presentation of t he subject i s contained in t h e monogram en t i t l ed The Taste Sense and the Relative Sweetness of Sugars and Other Sweet Sub-

stances", by the l a t e D r . A. T. Cameron of the University of Manitoba. I n this monogram flavor i s described as a mixture of various t a s t e s and odors.

It

I t i s also usually considered tha t there a re

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Taste var ies between races and between individuals and t h i s var i - a t ion i n some cases i s inherited. i n t h e taste sense of the individual from tine t o time depending upon num- eroua factors. been used largely, though supraliminal methods using concentrations well above the threehold l eve l have also been used. I n the discussion that follows it must be accepted tha t t he flavors i n questlon a re well above the threshold l e v e l and are common t o most individuals i n t h i s country.

There also appears t o be a wide variation

I n the study of tas te , liminal o r threshold methods have

Beef:

There i s a mass of information pertaining to the flavor of beef as a r e s u l t of breeding, sex, and feeding but much of it i s conflicting and of doubtful significance. flavor with improvement of breeding when pure bred bul ls a r e crossed with Brahama c a t t l e and scrub ca t t l e , but the improvement is not marked. Where normal feeding practices were conducted there was no s ignif icant differences a8 a result of feeds o r methods of feeding, though increased fat seemed t o produce 8ome improvement i n flavor. ence i n flavor of beef resul t ing From feeding on grass or s t r i c t l y grass f a t ca t t le . flavor noted a t North Dakota i n c a t t l e grazed on very sparce pasture i n 1934. This was a t t r ibu ted t o the consumption of cer ta in weeds or grasses not normal- l y consumed. From t i m e t o time cer ta in weeds have been accused of producing off f lavor of beef but the only factudi information related t o any one weed comes from Geor- gia where wild onion was shown t o produce a strong flavor i n the rounds, loins and shouldera of beef fed wild onion. the flavor, nei ther did various types of treatment of the carcass. T h i s f lavor does disappear, however, i f no wild onion has been consumed within several days before slaughter.

There seems t o be a trend towards improvement of

There 8eems t o be no s ignif icant d i f f e r -

One exception t o the latter was the very intense and undesirable

The undesirable flavor disappeared a f t e r feeding i n dry l o t .

No form of cooking appeared to remove

Work at Nebraska and Miseouri Stations indicate that flavor in - creases w i t h age from calf-hood t o maturity. by Barbella and others of the U.S.D.A. a l s o bears out t h i s observation. same study confirms the observations of numerous other8 regarding the in- creased flavor w i t h increased degree of f inish.

A n extensive s t a t i s t i c a l study The

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Lamb:

Retarding the growth of lambs, e i ther by feeding ample amounts of roughage only, o r by feeding insuff ic ient amunts of a ra t ion consisting of grain w i t h roughage, measurably reduced the des i rab i l i ty o f flavor and also reduced the tenderness of the meat. Submaintenance rat ions have been sighted by several experiment s ta t ions as influencing the pa la tab i l i ty adversely, but the Nebraska Station seems t o be the only one that specif ical ly mentions the lowering of the flavor value. The influence of breed has also been studied by a number of s ta t ions but intensi ty or des i rab i l i ty of the flavor has not been included among the Obser~8tiOnS. Contrary t o common opinion, f a i lu re t o css t ra te ram lambs u n t i l they a re one year of age has no measurable influence upon the pa l a t ab i l i t y factors either before o r after castration according to observations a t Cornell, Maryland, Tennessee, Vermont, and the U.S.D.A.. I n general a l l work done with lamb indicates an increased des i rab i l i ty in aroma and flavor with an increase i n the degree of f in i sh .

Fork:

Pa la t ab i l i t y of f resh pork, par t icular ly flavor seems t o have been overlooked i n the majority of pork studies. the observations. Breed has no influence upon flavor. Plane of nu t r i t ion seems to have no s ignif icant bearing upon pa la tab i l i ty , though the North Carolina Station observed tha t l imited feeding of hogs from weaning t o slaught- e r produced a more pronounced flavor and aroma than those full fed. However, those hogs receiving a l imited rat ion throughout t h e feeding period produced pork grading lower i n pa la tab i l i ty than the full fed pigs, but w a s not objec- tionable. of hoga, from 145 pounds t o 300 pounds, but t h i s may be due t o the increased deposits of fat .

The following summarizes most of

There appears to be some improvement in flavor w i t h increased weight

Although the work on sof t pork i s voluminous there are very f e w observations on flavor. pork seems t o be i n appearance only. f lavor of soft pork i s preferable to that of f i r m pork. of protein supplement including fish m e a l seems t o have no influence upon the flavor, though it may influence the firmnessof the pork.

The primary difference between so f t pork and firm The Georgia Statson suggests t ha t the

The kind or amount

The type of feed including pasture has no influence upon the flavor though there a re a few notable exceptions. produce pork that i s objectionable i n both aroma and flavor, thoughthe causative factor ha8 not been isolated. The Nebraska Station found tha t grain t reated with paradichhrobenzene as an insect ic ide when fed t o hogs even i n a very l imited amount produced f resh pork so objectionable that it w a s inedible. The cured products were likewise inedible and caustic ref ining f a i l ed t o re - move the odor and flavor from the lard.

Rye grain has been observed t o

All i n a l l the references t o f lavor a re ra ther limited, probably due t o the lack of specif ic methods of measurement. Undoubtable there a re many other chemicals t h a t might have an influence upon the f lavor of the m e a t similar t o tha t of paradichlorobenzene, but it i s fortunate t h a t they a re not l i s t e d among the items comonly fed t o livestock.

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Dressed and Frozen Meat:

There seeme t o be very l i t t l e factual information on t h i s phase of the subject, but there a re many observations that seem t o be generally accepted though not backed with experimental evidence. foods have been described as nutty, metall ic, brassy, b i t t e r , turpentine and sour. par t icu lar ly warm beef' should be avoided a8 the fresh meat will absorb the aromatic gases given off by the f r u i t s and vegetables. cayed potatoea, cabbage, and le t tuce have been known t o cause such off f lavors t ha t la rge quantit iee of meat have been replaced. no means uncommon during the period of expansion of the locker industry.

Odors and flavors of frozen

The etorage of fresh f r u i t s and vegetables i n the same cooler with meat,

The presence of de-

This si tuat ion has been by

It i s recognized t h a t aging meat has a desirable influence upon the flavor, but aging for too long may produce a f lavor that i s too "gmey" t o s u i t many $alates, therefore aging should be limited, par t icular ly if the meat is t o be preserved for a period of time by freezing. develop during aging as a r e su l t of bacter ia l growth on the outside of the car- cass. growth of putrefactive organlams can frequently be observed, (unpublished data) observed that growth of this organiem was slow a t 34'F but abundant growth was noted a t 40%. When the organism was isolated and plated bacteriologically, it was found t o be a gram negative, small rod shaped, psy- chrophilic organism. When grown on Difco's North Nutrient agar a very putr id odor was evident. Henrick- son has c lass i f ied t h i s organism as Alcalegenese Metalcaligenes, and it i s f e l t t h a t it i s the cause o f numerou~ compaainta of off flavored meat when the meat is removed from the locker only a short t i m e af'ter freezing. surface of a contaminated cwca88 i s careArlly wiped before cutting, the power saw w i l l mear the sliw growth over the surface of t he cut meat and an obnox- ious odor and flavor i n t h e meat results. This i s a condition t h a t can and should be avoided bu t is happening far too frequently. be involved tn a similar manner with off f lavors i n meat,

Off flavors a l s o frequently

When fresh gmeat i s held in an aging room for short periods, a slimy Henrickson

T h i s organiem i s aerobic and grows best a t 23OC.

Unless the

Other bacter ia may a l s o

Spices have been obaerved t o give off flavor to ground meat and Only recently pepper was noted t o have a strong ucalyptas aroma which sausage.

f lavor it imparted t o the meat. have imparted a petroleum f lavor to the meat a f t e r a period of storage. papers should be avoided. pork roasts as an antioxidant. surface during the cooking process has been noted. t he eurface has given the product an added flavor which i n no case was recorded as objectionable. when added t o meat have produced an off f lavor , experimentally and a re not available on the market a s antioxidants,

There are some came on record where wax papers Such

Oat f lour has been added t o sausage and dusted over Under such conditions a s l i g h t charring of t h e

Th i s charred condition of

It has a l s o been reported verbally t h a t some antioxidant6 These materials were t r i e d only

A few years ago many locker rooms had an odor tha t w a s frequently deecribed as that "Locker Room Odor". f a c i l i t i e e , lower temperatures i n the storage room, be t te r ch i l l i ng f a c i l i t i e s and a general improvement i n the eanitary condition of the locker plant t h i s odor has prac t ica l ly disappeared. It was believed, and the disappearance of t he odor i n part substantiates the belief, that the odor was associated with bac ter ia l growth due t o lack of sharp f'reezing f a c i l t t i e s and i n some case6 t o actual decay of the foods etored i n the lackere due t o inadequate freezing. There is no question about the occurreace of the odor, and t h a t the packaging material absorbed the odor which i n turn influenced the f lavor of the food

With the ins ta l la t ion , of sharp freezing

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contained in the package. be t t e r sani ta t ion and be t t e r management seem t o have pract ical ly eliminated this type of contamination. I n the e a r l i e r days of locker plants when wood w a s used extensively i n the construction of the lockers there were numerous cases where the wood sealer and paint flavored the products placed i n the locker. Turpentine has been known t o impart a bi t ter t a s t e t o food products. It should be mentioned, however, t ha t during the period these things happened the wrapper paper w a s poor and eharp freezing f a c i l i t i e s frequently lacking.

Lower temperatures, improved wrapping material,

Dehydration i s s t i l l with us and with dehydrated meat there i s a flavor tha t though probably not obnoxious, i s cer ta inly not desirable. flavor i s d i f f i cu l t t o describe but is one that a l l member of a pa la tab i l i ty panel recognize immediately. Again improved wrapping materials, improved wrapping, and more constant storage temperatures a re aiding in the elimina- t i o n of t h i s condition. Rancidity, though not necessarily so, i s usually associated with dehydration. The most common cause of off f lavors i n frozen meat today i s rancidity. Since some degree of oxidation takes place even i n a frozen s t a t e , rancidity w i l l develop if t he fats are stored too long. Pa la tab i l i ty of the meat, par t icular ly flavor drops rapidly with the onset of rancidity. Sharp freezing and lower storage temperatures a id i n delaying the onset of rancidity, some antioxidants have been used w i t h a f a i r degree of success, but when products containing unsaturated f a t s a r e t o be stored by freezing, they should be consumed within a reasonable period of t i m e o r some degree o f rancidity w i l l be noted.

The

Summarizing These Observations or Factors Related t o Flavor:

Age and degree of f in i sh have a desirable influence upon t h e flavor of a l l meat, feeds i n general have l i t t l e influence, though 8ome specif ic i t e m s may prove detrimental. flavor. I n no instance has freezing been auggested as improving the flavor of meat, but ra ther t o the contrary, there i s a slow and gradual deteriora- t i on o r lowering of the flavor from a des i rab i l i ty viewpoint. The matter of off flavors would seem t o be more a problem, of sanitation, temperature control i n both the c h i l l room and the storage room, proper packaging, sharp freezing, and do not s tore too long. for research open t o the food chemist i n determining some of the compounds re la ted t o of f f lavors. on the subject of f lavor in general.

After slaughter, aging alone improves the

It would a l s o seem as i f there i s a f e r t i l e f i e l d

There appears t o be great need for fur ther research

CHAIRMAN BRATZLEB: We have t i m e for about two questions. The open discussion w i l l be l ed by E. J. Wilford of Kentucky.

PROF. WILFORD: The paper by the speaker whojuet l e f t the f loor needs I think the paper has been w e l l writ ten and the ground ef f ic ien t ly no apology.

covered

Before 1 open the f loor t o discussion or questions, I think tha t he cleared up one point f o r me. I noticed when we were slaughtering some lambs that one group o f lambs seemed t o have a very strong flavor and other lambs o f similar type and breeding did not have tha t same t a s t e . The f i r s t lamb6 that I am talking about that had the strong flavor were very slowly grown and produced t h e i r gain very s lml~~ , L)thercr of the 6ame ki-d of breeding

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and feeding, were bettbr fed, grew much more rapidly and did not have that strong t a s t e . I n other words, slow growth seems t o develop that so-called

. mutton t a s t e .

Now we are open f o r diecussion o r questions on this paper b

PROF. EULL: I would l i k e t o ask the Professor how he l iked these ozone generators t o purify t h e air i n locker plants .

PROF. MACICTNTOSH: That was another note I scratched off w i t h in ten t , f irst , because I oould not f ind authentic material. on the subject, because personally I do not consider advertising material by the manufacturer a8 authentic, and l i k e Pete over there, I a m very acrupulous about what I believe any more.

Personally, I a m very much opposed t o it. I cannot help but f ee l that t h e presence of ozones i n t h e cooler very def in i te ly accelerates oxida- t ion. I f all our packages were put up absolutely i n an impermeable form, as Pete said, i f t h e wrappifig material was impervious t o gas - and we must pay more at tent ion t o that - we would have l i t t l e worry about it. them are not, and it i s purely my opinion t h a t t h e presence of those things i n the cooler and i n t h e storage room accelerates oxidation.

But most of

I am a f i r m believer i n the fac t t h a t it does not remove the cause. If someone ha6 an odor i n t h e i r f'reezer, it is t i m e they determined the cause and removed it, ra ther than t r y t o camouflage it,

PROF. BULL: Do you think Air-wick would do? (Laughter)

MISS LOWE: I think h v e y ' s paper was f ine, but I think there are a A s long as Fred and l o t of intangiblee, and I a m e w e he w i l l agree with me.

Davey and I have scored meat, we have not disoovered the cause for t he d i f fe r - ence i n the f lavor of a n i d e . t h e younger people t o go ahead on t h a t problem,

I am making t h i s comment because it is up t o

The Univereity of California i s working on the f lavor of chicken, and one of t he d is t inc t ive f lavors i n it i s caused by a weak acid. Regional Laboratory, they a re col lect ing the d i s t i l l a t e s and determining the chemical agents that are l inked with the f lavor of meat and also chicken.

A t t h e Western

Returning t o the subject of milk, since milk i s a f l u i d t h a t i s pro-

We can detect the flavor o f w i l d honey, skunkweed, and duced i n the body of a dairy a n i m a l , we can a l l t e l l when the cows are turned out on spring pasture. many other plants . I f you have watched a good milk m a n work, he can t e l l you whether the milk came from cows tha t were on s i lage, o r whether it was dry feed, and so on.

I think i n k i l l i n g the animals, when you take out t h e f lu ids , where those water-soluble consti tuents are, and t h e blood i s out, you leave such a small amount of t he f lavors that it i s r a the r intangible, but if you will observe a great work back. than we think. Crocker, i n using h i s pork, said he used an Eastern pork - he i s i n Boston - and an Iowa group, inherent, due t o t h e breed, o r due t o the feed, because it was d i f fe ren t from t h e regular pork f lavor tha t he mentioned.

many things as you are working w i t h tho meat, you may graduall: I wonder i f feed may not cauee more difference i n f lavor of meat

He eaid there i s a difference t h a t is e i ther

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A l l of you who have scored meat a long t i m e remember certain animals I jus t mentioned t o tha t have tas ted t e r r i b l e and others that were very good.

Fred a minute ago -- w a s it you who was a t the Station a t Iowa when w e had those animals that were fed on cocoanut feed? outside of two other animals, that I have ever eaten, and the meat came from one of the ani~nals fed cocomut feed. lmp2encd t o be the individual animal with a great many other character is t ics , it i s cer ta inly something t h a t need6 a l o t more investigation. It i s a wide- open f i e l d for a l l the youngsters t o begin on.

I t was the best t as t ing f a t ,

Whether it was the feed or it jus t

PROF. WILFORD: I think you have somethicg there.

PROF. MACKINTOSH: I think the statement of Miss Lowe regarding the probable influence of feeds i s quite c0rrec.t. below the average threahold. I think ev id9ce o f t ha t l i e s i n the case o f rye. Rye pasture i s oneof the things you carl t e l l the day the cow went on t o pasture by the t a s t e o f the milk, and it i s apparently strong enough t o influence the c a r c a s ~ . threshold leve l .

However, as indicated, they a re

Most other feeds, t o my m h d , may do such, but it i s below the

DR. NELSON: M r . C h a i r m a n , I would l i k e t o ask, do you consider t h i s rancidity i a induced by the u l t r a v io le t l i gh t due t o the radiation energy i t s e l f , or t o the ozone generation by the u l t r a v io l e t ?

PROF. MACKINTOSH: You have ne out i n too deep water.

DR. NELSON: You put yourself there.

PROF. MACMNTOSH: My opinion is t ha t it i s the ozone.

DR . NELSON: I wonder.

PROF. MACMNTOSH: We cannot get away from the fac t t ha t we do know Why shouldn't it, i n the case of meat, when tha t that accelerates oxidation.

you bring them i n contact?

DR. NELSON: d i f f i cu l ty qui te a few times when these wonderful lamps t h a t d i d everything were f i r a t developed. amount of ozone,

The reason I asked t h a t question, we had run into the

We found a l o t of them did produce a considerable

The question is: Why are you using an u l t r a v io l e t anyway?

PROF. MACKINTOSH: Opinion again.

PROF. BULL: I might add i n that connection that when Prof. Nelson was w i t h Wilson & Company he did more work with u l t r a v io l e t l i g h t s than all the r e s t of us here put together. I j u s t mention tha t because judging from his remarks, he does not have much use fo r them. have them.

A t l e a s t , Wilson does not

DR. NELSON: We were never successful wi th them. It i s a very f ine sc i en t i f i c tool i n curosity. application fram the laboratory in to a plant i s en t i re ly different .

You can have a l o t of fun w i t h them, but the

CHAIRMAN BRAT=: Thank you, Mr. Wilford.

I know the next gentleman can not say t ha t he does not know any- thing about the subject, because he was picked par t icular ly , I remember, as he had done some work with home freezers, and he will present the next paper on "Factors Affecting the Efficient Uee of Home Freezer Units i n Urban and Rural Homes," by E. A. Pierce of South Dakota.

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