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F A C T O R S A F F E C T I N G S T A B I L I T Y OF NEAT PlGNENtS
OEORQE E.
BRISSEY
There a r e undodbtedly many motivating f a c t o r s which a f f e c t the
homemakers' r e t a i l meat purchase. Chiefly among these, however, are her
experiences with her p a r t i c u l a r s t o r e and b r a d s , Price too has a way of
making i t s e l f f e l t . But, when she i s "coming down t o the wire" i n making
her ultimate selection, there is nothing so important a s appearance. And of
the f a c t o i s t h a t go i n t o t h i s a t t r i b u t e , none is g r e a t e r than color.
Today's advanced technical knowledge gives us a measure of control
e can therefore c a p i t a l i z e on t h e tremendous s a l e s poof t h i s aspect. W
t e n t i a l created by t h e display appeal of f r e s h and cured meats through
proper development of meat's bright fresh color, t h e control of t h i s a t t r a c t i v e color and t h e proper display illumination of t h e meat cuts.
Freshly cut beef has a purple-red color t h a t has l i t t l e display
appeal i n t h e r e t a i l case. Good meat market practice allows exposure of
t h e cut meat surface t o the a i r (oxygen) t o develop the desired bright red
color. This allows the nIyoglobin t o be converted t o oxy-myoglobin and i s
accomplished i n a matter of minutes. A s i m i l a r condition is found i n lamb,
but i s not as pronounced a s i n beef. In pork and veal an a t t r a c t i v e color
i s present when t h e neat i s cut. The b r i g h t color of f r e s h meat w i l l remain as long as s u f f i c i e n t oxygen i s available and no discoloration f a c t o r s
Prolonged exposure
impose dark red, gray, gray-brown, o r gray-green colors
t o oxyGen
several hours o r days, w i l l bring t h i s about, a s w i l l surface
drying and b a c t e r i a l contamination t o be subsequently discussed.
-
.
Occasionally a dark-cutting beef carcass i s found. A s the name
implies, t h i s beef, when cut, is dull, dark-red o r b l a c k - r e d i n color and
prolonged exposure t o a i r does not brighten i t s color, The incidence of
dark-cutters may increase if animals a r e subjected t o severe changes i n
handling p r i o r t o slaughter. A s a matter of f a c t , t h e condition may be
brought about p r a c t i c a l l y a t w i l l through preslaughter treatment, In t e s t s
a t t h e University of Missouri, dark-cutters were produced by simulating
severe s t r e s s conditions through the i n j e c t i o n of Adrenalin i n t o the l i v e
animal once each day on two days p r i o r t o slaughter. A s of this date, however, the meat industry does not h o w how t o e n t i r e l y eliminate dark-cutters.
It is important t o note that the eating q u a l i t y of such beef i s not impaired.
Occasionally, two-tone meat carcasses occur i n beef, lamb o r pork.
In such meat one m s c l e may be bright and another muscle f r o m the same carcass may be dark red i n color. O f course, there i s the n o m 1 difference i n
non-working nuscles. A s
pigmentation between the so-called working versus
with dark-cutting beef, there i s no solution t o t h i s problem a t t h e moment.
O f increasing inportance t o t h e swine industry is t h e growing incidence of
pale, watery pork. Workers a t the University of Wisconsin and others have
done much t o elucidate the incidence of t h i s condition and t o determine the
environmental f a c t o r s which cause it t o occur. The condition i s manifested
i n a low, ultimate pH, with some muscles being exceptionally pale t o almost
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98
translucent i n appearance, a varying two-tone condition with a flabby,
exudative surface. Among the Immediate f a c t o r s responsible for i t s
appearance a r e feeding, a c t i v i t y , temperature and r a t e of carcass c h i l l .
There is evidence that t h e basic cause, however, resides i n genetic fwtors
which have been bred in during the great emphasis on the development of t h e
meat-type hog. This author's experience of 1 2 t o 15 years ago was t h a t the
pH of pork muscle t i s s u e would vary in the range of 5.5 t o 6.5 with the
In recent time, we have observed a pH as low as
average being 6.0 t o 6.2.
4.8 with the general range running from 5.0 o r 5 . 1 t o 6.5 with the average
I n one s e r i e s of studies a t tlisconsin, t h i s pale,
a t about 5.6 t o 5.8.
watery pork was shown t o avemge about 305 a t one p a r t i c u l a r packing plant
with an occasional incidence as high as 70$ i n the case of the heavier
(18-20 l b . ) weight range of hams.
I n order t o maintain the desired color of meat, it is necessary
t o recognize what conditions protect t h i s color,what conditions cause discoloration, and what kind and amount of l i g h t provides the b e s t color rendit i o n i n the display came. S l x general areas a f f e c t i n g t h e protection and
proper illumination of meat will be discussed:
1. Sanitation
2. TmpemtUre
3. D r y m
4. Packaging
5. Freezing
6. Lighting
The e f f e c t s of these f a c t o r s are usually more pronounced and occur
more rapidly on aged meat o r meat that has been inproperly handled than on
freshly dressed o r processed meats.
The e f f e c t of poor housekeeping leadt o poor s a n i t a t i o n is
marked. Pronounced surface discoloration can occur in l e s s than one hour i f
t h e meat surface i s brushed with a heavy b a c t e r i a l inoculation. Such a cond i t i o n can happen with direct contact with an aged piece of meat, uncleaned
blocks o r c u t t i n g boards, and dirty equipment. Any practice which increases
the surface b a c t e r i a l load on meat cuts w i l l promote surface discoloration.
In t h i s connection, however, it f a i n t e r e s t i n g t o note the i n h i b i t i n g e f f e c t
of phosphate curing i n delaying the onset of greenish b a c t e r i a l discoloration i n ham. Paired hams were cured with and without phosphate, processed,
a s e p t i c a l l y sampled, gmund, -placed i n s t e r i l e petri dishes, and s t e r i l i z e d
with ethylene oxide gas. The samples were then inoculated with cultures of
known "greening" organism and incubated at 100' F. The non-phosphated ham
turned green i n l e s s than f o u r hours while i t s paired phosphated mate rem i n e d normal in appearance f o r a t l e a s t double that time.
Poor colors of cut meat surfaces a r e d i r e c t l y correlated with surface meat spoilage. It is therefore n a t u r a l and expected t h a t the rate of
discoloration of meat cuts in the display case is increased with increased
storage temperature. Meat cuts displayed a t 38042 F w i l l , i n general, discolor in one day, whue cuts displayed a t 32-34 F may maintain exceLlent
color f o r periods of up t o three o r four days. In general, the n o m 1
spoilage bacteria on cut meat surfaces, a t these r e l a t i v e temperatures, w i l l .
multiply t e n times more rapidly with each f i v e degree increase in temperature.
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99
Improper s a n i t a t i o n and poor temperatures can combine t o bring on discolorat i o n and spoilage within a matter of a few hours.
An unattractive b r i c k red color r e s u l t s a s cut meat surfaces l o s e
surface moisture and dry. Low humidities, excessive a i r movement and nonmoistureproof p a c a g i n g material promote surface drying. Surface drying
does not e n t i r e l y i n h i b i t surface b a c t e r i a l growt'n. Thus, protection
against drying may s e t up a moist surface condition that requires optimum
s a n i t a t i o n measures and temperatures if' more than one day's display case
l i f e i s desired.
Since packaging materials a r e available which w i l l give any degree
of oxygen and moisture permeability, it i s possi5le t o maintain good color
wlth proper p a c b g i r g materials o r t o promote discoloration through the use
of improper packcging materials o r materials improperly applied. It i s well
known t h a t freah m e a t packnging films w i l l maintain t h e bloom of t h e meat
f o r several days i f proper care is taken t o maid against other discoloration factors.
When a non-moistureproof film i s used, a dried surface and hard
b r i c k red c o l o r develops i n a very short time.
With f r e s h meat the use of a vacuw package and an oxygen impermeable film will always produce a d u l l purple-red color. It i s generally
accepted that t h t s d u l l purple-red color does not have the appeal of the
b r i g h t red color maintained with proper fresh meat packaging film, However,
a vacuum package does provide a longer display case l i f e . This resuIt6,
because of the f a c t that t h e vacuum package, and t h e oxygen impermeable
f i l m provide a nearly oxygen f r e e package which i s not conducive t o t h e
growth of the normal 8,poFtage bacteria found on meat. Tbere is a growing
u t i l i z a t i o n of vacuum packages on fresh ground meat. The consumer has
found that when the meat i s removed from the package, t h e c h a r a c t e r i s t i c
b r i g h t red color i s quickly formed.
Freezing and storage temperatures of frozen meat have a marked
influence on color. A quickly frozen cut of meat has a b r i g h t red color.
A slowly frozen cut is dark red i n color. Quick freezing produces small i c e
c r y s t a l s and when the meat is thawed the d r i p loss i s less than i n the
slowly frozen out where l a r g e r i c e c r y s t a l s have been formed i n t h e meat.
Frozen meat when stored a t r e l a t i v e l y high temperatures - 10°F t o
2
5
'
F
.
,
w i l l d i s c o l o r even though it was o r i g i n a l l y quick frozen and did
o r i g i n a l l y have a b r i g h t red color. The rate of discoloration can be vcly
rapid, a matter of j u s t a few weeks a t temperatures around 25OF. bbch of
the discoloration of f r e s h frozen meats i n f r e e z e r display cases is due t o
t h e f a c t that the frozen meat cuts are not held a t temperatures of 0%' o r
lower.
The position of the meat cuts i n the case can a f f e c t t h e color of
t h e packaged meat i t e m . Very often t h e package is placed too high i n the
case and does not have the advantage of t h e proper f r e e z e r temperature. I n
addition, the f l u c t u a t i o n of temperatures due t o defrost cycles and surface
warming due t o radiant heat f r o m high i n t e n s i t y l i g h t contribute t o more
rapid discoloration i n t h e display case than is found i n a closed freezer.
100.
Everyone has noted the frost that accumulates i n a package when
the packaging f i l m is not i n close contact with the meat surface. Wherever
such f r o s t a m e a r s and whenever a non-moisture-proof packaging film i s used
freezer burn w i l l . devehp. Freezer burn detracts from the appearance of the
meat and if' it continues t o develop under prolonged storage, w i l l cause a
decrease i n the juiciness of the meat and rasry lead t o undesirable flavor of
the meat when cooked.
The e f f e c t of good and poor illumination is most s t a r t l i n g . The
i n t e n s i t y of l i g h t i t s e l f is most hnportant. Case and store lighting has
been constantly increased. Stores toda3 have as much as 200 foot candles
of light, sometimes over 100 foot candles of liGht a t the l e v e l of the meats
i n the display case. Waf displays that had 30 foot candles of l i g h t a t the
product now have 60-80 foot candles o r m o ~ . The b r i l l i a n c e of the display
i s greatly enhanced by increased l i g h t intensity.
There is som question concerning possible undesirable e f f e c t s of
high intensity l i g h t levels. It may be t h a t radiant heat from such intense
l i g h t actually causes an increased temperature on the surface of the meat.
Such an increase in temperature could, of course, promote the r a t e of
b a c t e r i a l growth and a s a r e s u l t promote discoloration. lhcandescent l i g h t ing has been developed using special f i x t u r e s t o provide high l e v e l l i g h t
i n t e n s i t y without excessive heat and is o r soon w i l l be conmtercially available, In addition, if there is any u l t r a v i o l e t radiation a t the high int e n s i t y l i g h t levels, discoloration will be increased because u l t r a v i o l e t
l i g h t will discolor f r e s h meat cuts, Under r e l a t i v e l y normal l i g h t i n g
i n t e n s i t i e s of 50 foot candles or under f r e s h meat does not aiscolor i n a
matter of one o r two days display case l i f e .
Irkether t o use incandescent l i g h t s , fluorescent lighting, o r a
combination of these two is 8 matter of opinion. Everyone l i k e s t h e color
rendition secured with incandescent lighting. bhny believe t h a t proper
fluorescent tubing produces an excellent display e f f e c t . Improper fluorescent tubing, however, can produce a very unsatisfactory display.
Color enrichment possible with special colored l i g h t s i s a very
questionable practice. As long as the meat remains under these lights
the qpearance i s outstanding. If t h e shopper notices the neat package
a f t e r she leaves t h e display and finds the color undesirable, she may
drop the package most any place i n the store.
Discoloration I s the most important problem connected with
the marketing of cured, smlced, and Table-Ready Meats. This does
n o t mean t h a t t h e factors of sanitation, temperature, drying, packaging,
freezing, and lighting which were discussed i n the relationship to
f r e s h meats should not be given equal consideration i n the handling of
cured, smoked, and Table-Ready Meats. In general, however, any cured
meat item Will discolor aa t h e r e s u l t of display under l i g h t s before
any of the above mentioned f a c t o r s become effective. Discoloration in
these prOCe66ed meat items occurs when the cured meat pigment i n the
processed product combines with the oxygen of the air t o produce brown,
grey brown and grey green discolorations. Vacuum packaging, of course,
admirably takes care of t h i s . As opposed t o fresh meats, the cured meats
r e t a i n t h e f r desired pirilrish-red color in the aksence of oxygen. This chemi c a l reaction of the cured meat pigment and oxygen is accelerated when the product
101.
i s displayed under l i g h t and the r a t e of change o r reaction i s correlated
with the i n t e n s i t y of the l i g h t . Intense l i g h t can stimulate t h i s oxidative
process so that the bloom of f r e s h l y s l i c e d product can be l o s t within a
period of one hour o r even less. On the other hand i f the i n t e n s i t y of the
l i g h t i s maintained a t under 30 foot candles, b r i g h t color can be retained
f o r a t l e a s t one-half day i n non-vacuum packaged product.
Fluorescent
l i g h t s do not discolor cured meats more rapidly tlm incandescent l i g h t i n g .
A s long a s the l i g h t i n t e n s i t y i s t h e same t h e meat discoloration problem
will be j u s t a s severe regardless of t h e source of l i g h t .
I n a previous discussion c h a r a c t e r i s t i c s and properties of meat
pigments were presented. In the present paper an attempt was made t o show
t h e p r a c t i c a l implications of these c h a r a c t e r i s t i c s and properties by discussing t h e e f f e c t s of common, simple f a c t o r s such as oxygen, temperature,
bacteria and l i g h t on the s t a b i l i t y and appearance of meat pigments.
MR. SAFFLE:
Thank you very much, George.
i7e have ample time f o r a discussion, i f anybody has a
question they would l i k e t o a s k e i t h e r one of the previous three
speakers ?
--
In the l a s t year
George, I'd l i k e t o ask one myself
o r two we have seen a great d e a l more emphasis put onto vacuum
packaging, p a r t i c u l a r l y of ground meat, and using something where
we do not see through the film. From an i n d u s t r i a l standpoint do
you think t h i s will become more important and a major way of
s e l l i n g ground meat o r not?
MR. BRISSEY: Yes, I think t h i s movement i s d e f i n i t e l y
i n t h i s d i r e c t i o n t o pre-package ground meats a t the packer l e v e l
f o r d i s t r i b u t i o n t o the r e t a i l trade. The f a c t that t'ne pigment
changes s o rapidly upon exposure t o oxygen o r t o t h e a i r so t h a t
the homemaker, i f she does see through the package and sees the
brown surface on the package, t h e minute she cuts it she g e t s the
desired b r i g h t red color.
MEt. ZAFFZE: I might mention one thing of interest,we
have one chain s t o r e i n Georgia who came out w i t h what they c a l l
a p r e s t i g e steak, and it i s a high-quality steak cut extra t h i c k ,
and they wrap it i n a vacuum package and it has t h e purple color
of myoglobin, and a c t u a l l y they use t h i s a s a s a l e s point and, if
anything, it has gone over b e t t e r than if it had the red color.
A s you go down the showcase you immediately see t h i s purple color
and it stops you f o r a moment and you end up reading t h e i r l i t t l e
advertisement above it, and they do put out a top-notch product
and i n this p a r t i c u l a r case they have taken something which we
said they couldn't do and W e it i n t o a s e l l i n g point.
Are there any other questions anybody might l i k e t o ask?
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102
ME?. VERN CARILL (Ohio State) : Is there any evidence
that a product which has been vacuum packaged w i l l have a shorter
shelf l i f e than one that i s open?
MR. BRISSEY: The question is, is there any evidence t o
indicate t h a t a vacuum-psc3taged product wiU have a s h o r t e r shelf
l i f e than one that is open?
I can't think of anything with respect t o freshness,
however, because of t h e metabolic processes going on i n the vacuum
package iP you have had some of these peroxides that Dr. Fox mentioned in curing these items which have been vacuum-packaged. I
have seen these cured meats t u r n green within t e n minutes a f t e r
opening t h e vacuum package when they were a perfectly bright red
color as l o n g a s the vacuum package w8s present, and the discolorat i o n would take place very, very rapidly once it is removed.
MR.
,%ETLE:
A r e there any other questions?
If not, Jim, we w i l l gut you back on time schedule, and
even gained some, which I guess is unusual.
CHAIKMAN KEMP:
Thank
YOU,
Bob.
A t t h i s time we wiU have the report of t h e W e r a h i p Committee,
and George Wellington, we w i l l t u r n the program over t o you.
m. GEORGE WEUIIVmN
(Cornell) : Thank you, Jim.
report I s very b r i e f , and I think it w i l l consist f o r the
mst part in passing out the Directories. Mtny of you have received a
copy of the Directory which has been available f o r the past few days; I
know there are many here who did not receive it so I w i l l Just pause a
minute while it it3 passed out.
The M e r s h f p Committee consists of Adams, Bratzler, Bray,
assigned the Committee he gave us
Cahill and a y s e l f , and a8 Chainnan
these r e s p o n s i b i l i t i e s : First, t o publish the Directory, and t h i s we t r i e d
t o do knowing that there would be some incmpletions. Gle did the b e s t we
could with it. We laow that there are 8ome errors i n it, an6 we a r e sorry
where it is incomplete. We have tried t o make it accurate t o the extent
that it agree with the yellow sheet which hat3 been submitted. I hope that
it is correct to that extent.
I think you w i l l pmbably be interested i n knowing that we took
bids on the cost t o p r i n t 1,000 copies. We had bids ranging from about
$900.00 up t o about $1,450.00.
Actually we gave the job t o the lowest
bidder. Due t o the selection of the cover material there was a l i t t l e more
cost t o t h e p r i n t e r than we had anticipated. The final b i l l was about
$950.00, eo these copies cost about .9S# each. I think when and if it i s
done again we probably could do a b e t t e r Job by getting, more complete