xt7wst7dt126 https://exploreuk.uky.edu/dips/xt7wst7dt126/data/mets.xml   Kentucky Agricultural Experiment Station. 1969 journals 176 English Lexington : Agricultural Experiment Station, University of Kentucky Contact the Special Collections Research Center for information regarding rights and use of this collection. Kentucky Agricultural Experiment Station Progress report (Kentucky Agricultural Experiment Station) n.176 text Progress report (Kentucky Agricultural Experiment Station) n.176 1969 2014 true xt7wst7dt126 section xt7wst7dt126 ' 9 I1 CB
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 PROGRAMS FOR I968 ANIMAL SCIENCES FIELD DAYS
DAIRY FIELD DAY
July 2, I968—University Coldstream Dairy Center, Lexington
· Conducted tours ot demonstrations and exhibits showing recommended
practices and solutions ot current problems Facing the dairy industry
beginning at IO:OO a.m.
- Lunch provided by American Dairy Association of Kentucky, Louisville,
Aubrey Feed Mills, Louisville, and Southern States Cooperative, Lexington,
Sealtest Foods, Louisville, and Kyana Milk Producers Association, Louisville.
- Address -- "Dollars and Sense of Programmed Dairy Herd Health" -
Dr. David A. Morrow, Department of Animal Science, Cornell University,
Ithaca, N . Y.
LIVESTOCK FIELD DAYS
July IO, I968-University Coldstream Farm, Lexington
July I2, I968··Western Kentucky Substation Farm, Princeton
· Conducted tours of beef, sheep, swine and horse research at regular
intervals beginning at 9:00 a .m .
- Lunch provided by Bluegrass Stockyards, Lexington, and Field Packing
Company and Owensboro Milling Company, Owensboro
- Address -- "Future of Agriculture in Kentucky" · Honorable Louie B. Nunn,
Governor, Commonwealth ot Kentucky

 KENTUCKY
ANIMAL SCIENCES RESEARCH REPORTS
1968
PROGRESS REPORT 176
July 1968
UNIVERSITY OF KENTUCKY
AGRICULTURAL EXPERIMENT STATION

 CONTENTS
Page
ANIMAL FOODS SECTION
Keeping Quality of Fluid Dairy Products Obtained at Retail Outlets . . . 5
Effect of Sanitizers on the Freezing Point of Milk ............ 7
Factors Affecting Consumer Acceptance of Chocolate—Flavored Milk . . 8
The Effect of DDT, Dieldrin, and Heptachlor on the Growth of
Selected Bacteria ........................... 9
Effect of Casein on Dechlorination of DDT and Inhibition of Growth .
by Heptachlor ............................. 10
Effect of 2, 3, 5—Triphenyl-Tetrazaloim Chloride (TTC) in Plating
Media on the Enumeration of Psychrophiles ............. 11
Effect of Cocoa Powder on the Growth of Bacteria ............ 11
Effect of Bacillus Subtilis Protease and Sodium Tripolyphosphate on
the Quality of Aged Hams ....................... 13
Effects of Aging Temperature on Aged Ham Quality ........... 14
Effect of Fresh Ham Quality and Aging Temperature on Quality of
Aged Hams ............................... 15
Effects of Salt, Moisture and Aging Time on the Viability of
Trichinella Spiralis in Dry-cured Hams ............... 18
Effect of Fatness and Fresh Pork Quality on Yield and Quality of `
Ham and Bacon ............................ 19
Carcass Traits of Lambs of Different Gaining Ability and Slaughter
Weights ................................ 22
Heritability Estimates of Some Lamb Carcass Traits .......... 24
Effects of Rate of Gain and Weight at Slaughter on Certain Quality
Characteristics of Lambs ....................... 25
GENETICS AND PHYSIOLOGY SECTION
Selection for Oxygen Consumption of Three—week-old Chickens ..... 28
Measurement and Selection of Economically Important Traits in
Beef Cattle .............................. 28
An Evaluation of Six Chemical Tests for Pregnancy in Cattle ...... 30 _
A Survey of Dairy Farmers Concerning Breeding and Management
Practices ............................... 31
The Effect of Irrigation and Nitrogen Fertilization on the Nitrate
Content of Sudex Forage ....................... 32
Effect of Herd Size on Fertility and Delayed Returns .......... 32
(2)

 Page
GENETICS AND PHYSIOLOGY SECTION (continued)
The Relationship Between Nitrate Content of Forages and Dairy
Herd Fertility ............................. 32
Effect of Pronase on Subsequent Development of Mouse Embryos .... 33
Feed Intake and Embryo Survival in Gilts . . · ............... 33
_ Selective Breeding for Earlier Lambing in Southdown Sheep ....... 35
Effects of Unilateral Castration on Body Weight and Accessory Gland
Development in Ram Lambs ..................... 37
Comparison of MAP and Progestogen Impregnated Vaginal Sponges for
Synchronizing Estrus in Ewes .................... 39
Pituitary Gonadotropin Levels at Different Stages of the Estrous
Cycle of the Ewe ........................... 40
Oxygen Consumption by Sperm Cells from Heat—stressed Rams ..... 41
Causes of Infertility in Beef Cows .................... 42
ANIMAL NUTRITION SECTION
The Rehabilitation of Cage Laying Hens .................. 44
Effects of Rearing Method and Protein Phase Feeding on the
Reproductive Performance of Cage Laying Hens .......... 46 ’
U Effect of Pantothenic Acid Level on the Utilization of Energy and
Nitrogen by the Chick ......................... 48
Effects of Protein Level of the Diet on the Reproductive Performance
of Japanese Quail (Corturnix corturnix japonica) .......... 51
Apparent Protein Digestion Anterior and Posterior to Equine Cecal
Fistulas ................................ 53
Digestion of Energy Sources by Equine Intestinal Microorganisms . . . 55
Volatile Fatty Acids in Equine Cecal Fluid ................ 56
Performance of S.P.F. Yorkshire Herd at West Kentucky Substation
from 1963 to 1967 ........................... 57
Effect of Protein Sources and Levels and Oral Iron for the Sow on `
Reproductive Performance ........... _ ........... 6 O
Effect of Dietary Fat, Protein, Cholesterol. and Ascorbic on Serum
and Tissue Cholesterol and Serum Lipids in Swine ......... 62
High Protein Rations for Swine ............... ` ....... 6 2
Protein Levels for Growing-finishing Pigs on Concrete ......... 63
A Comparison of Opaque—2 and Normal Corn for Pigs .......... 64 ·
Comparison of Free-choice and Complete—mixed Rations for
Growing—finishing Swine ....................... 64
(3)

 Page
ANIMAL NUTRITION SECTION (continued)
Interrelationships of Copper and Molybdenum on Performance of
Growing-finishing Pigs ........................ 65
Levels of Phosphorus for Growing-finishing Pigs ............ 65
Utilization of Urea by Lactating Dairy Cows ............... 66
Sulfur, Nitrogen and Amino Acid Balance, and Digestibility of Low
Sulfur and Sulfur Supplemented Diets Fed to Lactating Cows .... 67
Properties of Toxic Fescue Extracts ................... 68
Establishment of Microbial Activity in Pre-weaned Lambs ....... 68 ·
Growth and Development of Early Weaned Lambs ............ 70
Intake and Performance of Young Lambs ................. 70
Performance and Carcass Characteristics of Early Weaned Lambs
Slaughtered at Different Weights ................... 72
Influence of Vitamin A Deficiency on Renal Function in Ewes ...... 74
Biliary Secretion of Metabolites of Vitamin A and Beta—Carotene
in Sheep ................................ 74
Losses of Vitamin E from the Pre-intestinal Digestive Tract of Steers . 75
Effect of Concentrate Level on Pre-intestinal Disappearance of
Vitamin A ............................... 76
Effects of Iodinated Casein and Tapazole on Vitamin A Turnover ·
in Steers ............................... 77
Sulfobromothalein (BSP) Excretion by Sheep During Metabolic Stress . . 77
Protein Status of Sheep and Levels of Blood Acetate and Glucose .... 78
Post-ruminal Cellulose Digestion in Sheep ................ 79
Rumen Metabolite Utilization by Mature Rats .............. 80
Proline Metabolism During Cellulose Digestion by Rumen
Microorganisms ............................ 81
Volatile Fatty Acid Concentrations in Ruminal Fluid of Steers Fed
Chlortetracycline or Tylosin ..................... 81
Abomasal Nitrogen in Steers Fed Urea Rations ............. 82
Abomasal Nitrogen in Wethers Fed Different Protein Sources ...... 83
Effect of Oyster Shell With and Without Roughage in Beef
Finishing Rations ........................... 84
Urea and Molasses Supplementation of Ground Ear Corn Rations
for Feedlot Steers .......................... 86
Level of Intake and Feedlot Performance of Steers Fed Soybean
Meal or Urea ............................. 88
(4)

 -5..
ANIMAL FOODS SECTION
KEEPING QUALITY OF FLUID DAIRY PRODUCTS
OBTAINED AT RETAIL OUTLETS
B. E. Langlois, A. W. Rudnick, T. R. Freeman
` In an attempt to learn what the housewife can expect when buying fluid dairy
products, a 4—year study was undertaken. Samples of homogenized milk, low-fat
milk, chocolate milk, skimmilk, half-and-half and whipping cream were obtained
from retail outlets in Lexington, Ky. These were analyzed for flavor and bacterio-
logical qualities both before and after storage in the laboratory.
Procedure
The samples obtained were evaluated for flavor on the day purchased and after
4, 7, 10 and I4 days' storage at 45F. Samples scoring below 36.0 (40.0 perfect) were
considered unacceptable.
Bacteriological analyses were made on the day purchased and after storage for
7 days at 45F.
Results ‘
Average results obtained for each product examined are shown in Table 1.
Individual samples ranged in age from 0 (fresh) to 28 days old when purchased. ·
Products with the highest turn-over, i. e. homogenized and low-fat milk, were
freshest at time of purchase. Keeping quality (shelf—life in the home) after purchase
was directly related to the age of the product when it was purchased.
Homogenized milk, which is the industry's biggest seller, had the poorest
flavor when purchased. In general, however, flavor score at time of purchase cannot
be used to predict shelf-life.
Except for chocolate milk, whipping cream and half-and-half had the most
samples exceeding the legal bacteriological standard at time of purchase. There was .
little relationship, however, between total numbers of bacteria, or initial coliform
numbers, and the shelf—life of the product. On the other hand, the presence of large
numbers of psychrophilic organisms initially was a sign of a short keeping quality for
the product.
The greatest percentage (7%) of samples of homogenized milk were unaccept-
able because of flavor when purchased. However, except for low-fat milk the rate
of spoilage of homogenized milk during storage was less than that for the other products _
studied.
The results of this study show that the housewife is faced with these gambles
when she buys fluid dairy products:

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1. One chance in 20 that the product will be spoiled when she gets home.
2. One chance in 8 that it will spoil after 4 days in the refrigerator.
These odds go to 1 in 4 or 5 that chocolate milk or high-fat products will
spoil in this time.
3. The odds are from 1 to 5 to "even money" that the product will not keep
for a week.
I This study indicates that retail quality of many dairy products is not sufficient
to meet the challenge of "dairy substitutes."
EFFECT OF SANITIZERS ON THE FREEZING POINT OF MILK
T. R. Freeman and J. L. Buoy
The freezing point (FP) of normal milk is one of its most constant character-
istics. Consequently, the FP determination of milk is the most widely used method
of detecting the presence of added water. To use this control technic intelligently it
. is helpful to have an understanding of the possible effect on the FP of milk of other
contaminants that might gain access to such milk.
To meet sanitary requirements imposed upon them, milk producers find it
necessary to make extensive use of chemical sanitizers in readying milking and milk
handling equipment for daily use. Inevitably, traces of sanitizers will, from time to
time, be transferred from equipment to milk supplies. The purpose of these €Xp€1‘i·
ments was to find out if the presence of small amounts of commonly used sanitizers
would change the FP of the milk.
Three types of sanitizers were investigated: sodium hypochlorite, iodophor,
and quaternary ammonium chloride. These were each added to fresh milk in
concentrations of O, 10, 25, and 50 ppm. Freezing point measurements were made
after 0, 24, and 48 hr. Eight trials were conducted with each sanitizer.
Results obtained are summarized in Table 1. Apparently, the quarternary
ammonium sanitizers had no effect on the FP of milk. The iodophor and the hypo-
chlorite both lowered the FP slightly, with the iodophor having slightly more effect
than the hypochlorite. Seemingly, there was no difference whether the FP determi-
. nation was made immediately after adding the sanitizer or 48 hr later. Not shown in
the table is the observation that Jersey milk seemed to be affected slightly more
than was Holstein milk-although the difference was so small that it probably is not
significant. The presence of traces of sanitizer apparently had .slightly greater effect .
on the FP of 1ate—lactation milk than of early lactation milk, but again the difference
was probably too small to be significant.

 ...8-
Table 1. — Changes in Freezing Point (O C) of Milk After Adding Different Amounts
of Sanitizers
  I
 
Hours 10 ppm 25 ppm 50 ppm
Quaternary Ammonium Chloride
0 +.001 +.001 -.001
24 +.001 .000 -.001
48 +.001 +.001 .000
Ave +.001 +.001 -.001
 
Iodophor . `
0 -.004 -.009 -.015
24 -.003 -.007 -.015
48 -.002 -.006 -.014
Ave -.003 -.007 -.015
 
Sodium Hypochlorite
0 -.001 -.005 -.010
24 -.002 -.005 -.013
48 -.002 -.005 -.010
Ave -.002 -.005 -.011
 
FACTORS AFFECTING CONSUMER ACCEPTANCE
OF CHOCOLATE—FLAVORED MILK
O. Hampton, B. E. Langlois and A. W. Rudnick
Sale of chocolate-flavored milk has never reached the level expected by the
dairy industry, and the reasons for this are not known. A recent survey of this
station indicated a lack of uniformity in the composition of chocolate-flavored milk.
This study was made to determine the role of fat and solids-not-fat (SNF) in
the consumer acceptance of chocolate-flavored milk.
Procedure
With seven commercial cocoa powders, chocolate-flavored milks containing
0, 2 and 3.5% milk fat and 9, 10 and 12% SNF at each of the three fat levels were
prepared.
Milk samples were evaluated for flavor 2 and 4 days after preparation by a
panel of 5 experts and 15 consumers. In addition to flavor evaluations, the samples
were analyzed for viscosity, pH, chocolate level, and amount of fat and SNF.

 ..9-
Results
The pH of the samples was not affected by amount of fat and SNF, cocoa j
powder, or time after manufacture.
The chocolate level depended on the type of cocoa powder. In general, the
stronger the cocoa powder the higher the chocolate level.
V The viscosity increased with an increase in SNF, fat and time after preparation.
` The amount of SNF had a direct relationship to acceptance. At all three fat
contents, the more SNF present, the greater the preference. More fat in the samples
increased the preference. Amount of total milk solids seemed to have the greatest
effect on preference. Samples containing 3. 5% fat and 12% SNF (most total milk
solids) had the highest flavor score, followed by those of 3. 5% fat and 10% SNF and
2.0% fat and 10% SNF.
A The flavor score of the chocolate—flavored milks was increased on holding
them at refrigerated temperature. The samples had higher flavor scores 4 days
after preparation than after 2 days.
` THE EFFECT OF DDT, DIELDRIN, AND HEPTACHLOR ON
THE GROWTH OF SELECTED BACTERIA
J. A. Collins and B. E. Langlois A
Effect of chlorinated pesticides on bacteria in milk is of utmost importance
if tolerances for these residues are to be established for dairy products. This study
was made to determine the effect of DDT, dieldrin and heptachlor on the growth of
Escherichia coli, Pseudomonas fluorescens and Staphylococcus aureus.
Procedure .
Trypticase soy broth (TSB) and skimmilk were made up to contain 50 and 100
ppm of the desired pesticide. TSB and skimmilk without pesticide served as controls.
The samples and controls were inoculated with the test bacteria and incubated for
7 days. Bacterial numbers were determined, using standard plate count agar
immediately after inoculation and again after 1, 2, 4 and 7 days' incubation.
Results
Survival and multiplication of certain species of bacteria were affected in
varying degrees by the presence of chlorinated insecticides in the culture media.
E. coli in TSB and skimmilk was not affected by any of the insecticides at
the concentrations studied.
Both 50 and 100 ppm of DDT inhibited multiplication of g. fluorescens in TSB
after 2 days; however this organism was not affected by dieldrin or heptachlor in
TSB nor any of the pesticides in skimmilk.

 -10..
The multiplication of §. aureus was not affected by dieldrin in TSB or in
skimmilk containing any of the pesticides. DDT in TSB was inhibitory after 2 days.
Heptachlor had a bactericidal effect. Further study showed that 1 ppm of heptachlor ‘
in TSB would cause inhibition and that the bactericidal effect became pronounced at
10 ppm heptachlor.
EFFECT OF CASEIN ON DECHLORINATION OF DDT
AND INHIBITION OF GROWTH BY HEPTACHLOR
J. A. Collins and B. E. Langlois
Other work at this Station has indicated that skimmilk prevented the de-
chlorination of DDT by LE. coli and permitted the growth of S. aureus in the presence ·
of heptachlor. This study was an attempt to determine why such reactions occurred
in skimmilk and not in broth.
Procedure
Casein was obtained from fresh skimmilk and then fractionated into Alpha-,
Beta- and Gamma- casein. Whole casein and the casein fractions were added to broth
containing various levels of DDT or heptachlor.
The samples were inoculated with either E. coli·or §. aureus and incubated
at 370C for 7 days.
The samples containing §. aureus and heptachlor were analyzed for growth
every 2 hours the first day and then daily for the next 6 days. E. coli—DDT samples '
were analyzed for degradation products at daily intervals for 7 days.
Results
DDT was metabolized into several products by E. coli when grown in culture
broth. Approximately 95% of the p, p'-isomer of DDT was metabolized after
incubation at 370C for 7 days. The presence of whole casein in the culture broth
prevented the breakdown of DDT.
Growth of S. aureus was delayed for up to 2 days by as little as 1 ppm
technical heptachlor in broth, and it was completely inhibited by 10 ppm.
Addition of 0. 5% whole casein to broth containing 10 ppm technical heptachlor
permitted growth after 2 days. Growth began without any delay when 3% whole casein
was added,
The inhibition effect on the growth of §. aureus by heptachlor was reduced or
eliminated by the presence of whole casein in the culture media. Further research
indicated that all three casein fractions were needed to eliminate the inhibitory effect.

 -11-
EFFECT OF 2,3, 5—TRIPHENYL-TETRAZALOIM CHLORIDE (TTC)
IN PLATING MEDIA ON THE ENUMERATION OF PSYCHROPHILES
O. Hampton and B. E. Langlois
The present official method for the enumeration of psychrophilic bacteria
requires an incubation of 7OC for 10 days. Several methods using chemical inhibitors
and higher incubation temperatures have been developed in an attempt to shorten the
time required to determine psychrophiles. Most of these methods use TTC as a color
` indicator, either to change the color of a liquid media or to produce red-colored
colonies on solid media.
Studies at this Station have shown numbers based on TTC-media were generally
less than the standard method. Therefore, a study was initiated to determine the
effect of TTC on the enumeration of psychrophiles. Temperature of incubation was
studied as well.
Procedure
Standard plate count agar (SPC) containing 0 to 1% TTC was used for
enumeration. Pasteurized milk samples were obtained from retail outlets and
plated. The milk samples were replated after preliminary incubation (PI) at 12. BOC
for 18 hr. All plating was in quadruplicate for SPC and each SPC—TTC concentration
used. Incubation of one plate per set was at 7, 21, 25 and 320C for 2 to 7 days,
respectively.
Results
Sharp decreases in numbers were observed with increases in TTC level and
also increases in incubation temperature of samples examined before PI. Plates
incubated at 320C showed a linear decrease in numbers up to 0. 03% TTC where
growth was completely inhibited. Plates incubated at 7 OC were affected the least by
TTC. Little change in numbers was observed up to O. 05% TTC, at which point,
growth was increasingly inhibited until it was complete at 0.1%.
The effect of increasing levels of TTC on inhibition of growth was not so
pronounced when the samples were examined after PI but followed the same general
pattern as before PI. Complete inhibition occurred at 0. 7% TTC at 70C, 0. 3% at
21OC, 0.5% at 25OC, and 0.1% for 32OC.
Correlations of results obtained with SPC and SPC—TTC and the various
incubation temperatures were not very good except for SPC, and SPC-0. 1% TTC at
70C, and 210C.
EFFECT OF COCOA POWDER ON THE GROWTH OF BACTERIA
B. E. Langlois and A. W. Rudnick
Chocolate milk has a fairly poor shelf life according to a recent study con-
ducted by the authors. Little information is available concerning the microbiology

 -12-
of chocolate milk or the ingredients used for its manufacture. This study was con-
ducted to determine the role of cocoa powder in the growth of micro-organisms that
may bring about the spoilage of chocolate milk. ‘
Procedure
. Cocoa powders used in the manufacture of chocolate milk were added to broth
to give a cocoa concentration of 1. 5%. Broth alone served as control. The samples
were sterilized, cooled and inoculated in duplicate with Escherichia coli,
Staphylococcus aureus, or Alcaligenes viscolactis. The Samples were incubated at
70C, 250C, and 370C.
Changes in bacterialnumbers in both the samples and the controls were p
determined every 2 hours for the first 12 hours of incubation and daily for the next
4 days.
Results
E. coli
Cocoa powder apparently delayed the multiplication of E. coli for about 6 hours
at an incubation temperature of 370C, but then the organisms started to increase in
numbers rapidly and at the end of 24-30 hours reached the same level of numbers as
in the controls. Further change in numbers corresponded with change in the controls.
Cocoa powder appeared to have more of an effect on E. coli at 7OC incubation.
The numbers in the cocoa powder samples decreased throughout the incubation period
and were less than in the control.
_§. aureus
§. aureus incubated at 370C in the cocoa powder samples decreased in numbers
for 12 hours then gradually increased until at the end of 48 hr multiplication leveled
off . Maximum numbers in the samples were less than in the controls.
Cocoa powder appeared to have a bactericidal effect on §. aureus at 7OC,
inasmuch as numbers declined almost linearly in the cocoa powder samples incubated
at this temperature. Numbers after 2 days were less than half the number of §. aureus
inoculated.
A. viscolactis
Cocoa powder was bactericidal to LX. viscolactis at both 25 and 7OC. Numbers
decreased rapidly in the samples when compared with those in the controls. The
effect was even more pronounced in the samples incubated at 370C. Numbers were
quartered in 48 hr at 37OC and about halved at 7OC.
Cocoa powder used in the manufacture of chocolate milk appeared to inhibit
the growth of some common spoilage bacteria. This effect is apparent at refrigerated
temperatures as well as at the optimum temperature for the growth of the spoilage
bacteria. The degree of the inhibition varies with the bacteria.
-’_R

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EFFECT OF BACILLUS SUBTILIS PROTEASE AND SODIUM
TRIPOLYPHOSPHATE ON THE QUALITY OF AGED HAMS
James D. Kemp and Gregory Mayer
Production of dry cured hams is a sizeable industry and is increasing in
Kentucky. Since some hams lack tenderness, methods are needed for improving this
palatability trait. Commercial enzymes are used for tenderizing fresh meat.
Phosphates are used to enhance the water—holding capacity of commercially cured
pork. This project was devised to determine if a protease obtained from Bacillus
subtilis microorganisms would enhance tenderness when used alone or in combination
with sodium tripolyphosphate.
_ Procedure
Three groups of eight hams each were used. Group 1 was a dry—cured control.
Group 2 was pumped with 4% of distilled water which contained protease so that each
100 lb of ham received 9. 1 gm protease. Group 3 was pumped with 4% of distilled
water which contained protease and tripolyphosphate so that each 100 lb of ham
received 9. 1 gm protease and 172. 5 gm tripolyphosphate. Groups 2 and 3 received
the same curing treatment as group 1. Hams were cured for 2 days per pound, held
30 days for salt equalization, then smoked and aged for 4 months at 750F. Weight loss
was determined during aging. After aging the hams were cut, scored for aroma,
color, firmness and general appearance by a palatability panel for flavor, tenderness,
saltiness, and overall satisfaction and evaluated for tenderness using a Warner-
Bratzler shear.
Results
The control hams were uniform in color, firm and had a desirable general
appearance. Hams treated with the protease were variable. Most had a dark red
color. Five were slightly soft. One ham was spoiled and one had an acid aroma. Six
_ of the hams were excellent in general appearance. The protease—phosphate hams
were generally uniform in color but tended to be soft. Four had an acid aroma and
four were variable in color.
Weight loss was significantly (P ( .05) greater in the control hams through
2 months of aging. After 2 months the differences were not significant.
Tenderness as measured by the Warner—Bratzler shear was significantly
improved by the protease (P ( . 01 for the semitendinosus and semimembranosus
muscles and P ( . 05 for the biceps femoris muscle). The protease—phosphate group
was intermediate in tenderness.
Palatability tests showed that flavor and overall satisfaction scores were
significantly higher (P < . 01) for controls than for either treated group. Tenderness
again favored the protease group (P ( . 05) . There was no significant difference in
saltiness.

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Summary
Hams were treated as controls, with protease, and with a combination of
protease and tripolyphosphate. All were cured and aged alike.
Although the treated hams were more tender, the low scores for palatability
traits indicate that neither the protease nor the combination of protease and
tripolyphosphate is satisfactory for use in the production of aged hams.
EFFECTS OF AGING TEMPERATURE ON AGED HAM QUALITY
Thomas R. Lambuth and James D. Kemp `
The desirable flavor and aroma of country style hams are developed by
exposure to the natural warm summer temperatures. Because of the fluctuation of
temperature from day to night and from different times in the summer, the quality
of hams is not uniform and weight loss may reach as high as 30% during the aging
period. New techniques are needed to produce a more uniform product, to reduce
weight loss, and provide a more rapid turnover. This Station and others have worked
with various procedures and have had varying results. The objectives of this study
were to determine the optimum time, temperature and humidity for the rapid pro-
duction of highly desirable country style hams.
Materials and Methods
Two groups of 20 hams each weighing about 8 kg were cured using the normal
University of Kentucky procedure. After curing, excess salt was brushed from the
hams and they were hung for 30 days for salt equalization. After soaking in warm
water for 1 hour, the hams were hung to dry and then smoked for 18 to 24 hr at a
smokehouse temperature of 38OC. The hams were randomly allotted into two equal
groups. The first group was aged for 4 months at 240C. The second group was aged
with the first for 2 months at 240C and then at 35oC for the final 2 months. The
relative humidity was 60-65% for both groups. Hams were weighed when fresh, after
smoking, and at monthly intervals during aging. Free fatty acid content was
determined on subcutaneous and intermuscular fat on all hams. At the end of the
aging period, the hams were observed for color, odor and appearance.
Two 1. 3 cm center slices were cut from each ham and used in palatability
studies. These slices were broiled in an electric ovenfor 7 min on one side, then
broiled for 6 min on the other. The cooked slices were evaluated by a panel
composed of seven members, and the hams were scored for flavor, saltiness,
tenderness and overall satisfaction. Also a 2. 5 cm center slice from each ham was
cooked to 54OC, then turned and cooked to 760C internal temperature and tenderness
was measured by shearing 2. 5 cm cores from the semitendinosus, semimembranosus
and bicep femoris muscles on the Warner—Bratzler shear.
Data were analyzed by analysis of variance.
Results and Discussion
Weight loss increased during the aging period and was higher with the in-
creased temperature. The group aged at 240C for 4 months had an average weight

 ..15..
loss of 23. 8% at the end of the aging period. The average weight loss of the group
aged at 24OC for 2 months and at 35OC for 2 months was significantly (P ( . 05) higher
at 25.6%.
The free fatty acid values were higher in the hams aged at the higher tempera-
ture indicating a higher degree of aging.
After cutting, the hams were observed for color, general appearance and
aroma, with both groups being satisfactory and with little difference between groups.
The seven member panel found no significant difference in the flavor, saltiness
or overall satisfaction for the two groups, but they did find the 24-3 5OC group to be
significantly (P ( . 05) more tender than the 240C group.
Cores from three different muscles were sheared on the Warner-Bratzler
shear. The