Table Of Content.
I
ANTIBIOTIC RESIDUES IN MILK
//
ALICE KWENGWA CHEWULUKEI
Umv:“ SPnr  UMAiy  PLAC£D  m  THE
’A Thesis submitted in part fulfilment for
the degree of Master of Science in the University 
of Nairobi.'
1978
*
♦
UNIVERSITY OF  NAIROBI 
-  UBRARY
DECLARATION
(a) This thesis is my original work and has not been 
presented for a degree in any other University.
Alice Kwengwa  Chewulukei
(b) This thesis has been submitted for examination with 
my approval as University Supervisor.
&-/o
Professor I^.D. Naf^tad
EXTERNAL EXAMINER
Professor Folke Rasmussen,
Professor of Pharmacology, Royal Veterinary 
and Agricultural College,
Department of Pharmacology and Toxicology, 
13, Bulowsvej,
1070 Copenhagen V,
DENMARK
INTERNAL EXAMINERS
Professor 1.0. .'hfstad,
Department of Public Health, Pharmacology 
and Toxicology
Professor K.J. Lindqvist,
’  /v
Department of Public Health, Pharmacology 
and Toxicology.
LIST OF CONTENTS
PAGE
ACKNOWLEDGEMENTS
(ii)
LIST OF TABLES
(iii-iv)
LIST OF FIGURES
(v-vi)
LIST OF APPENDICES
(vii-viii)
ABSTRACT
(ix-xi)
INTRODUCTION
1-10
LITERATURE REVIEW
11-46
MATERIALS ANO METHODS
47-57
RESULTS
50-67
DISCUSSION
60-75
CONCLUSION
76-77
REFERENCES
70-99
APPENDICES
100-102
(ii)
ACKNOWLEDGEMENTS
I am highly endebted to Professor N. Gyrd-Hansen for 
his encouragement and constant advice throughout the course 
of this project.  His patience and willingness in the 
discussion and correction of several drafts of this manu
script. is appreciated.  I am grateful to Professor Tjaberg 
for his comments on the practical aspect of this project 
and to Professor I. Nafstad for reading through the final 
draft of the thesis.
I wish to extend sincere appreciation and thanks to 
those named below who kindly contributed to the success of 
this project:
The managers and the staff of K.C.C. for their cheerful 
cooperation and assistance during the exercise of milk sampling.
Dr. Arimi for his cooperation and assistance.  The technical 
staff of department of Public Health, Pharmacology and 
Toxicology who have been involved in the project practically, 
for their faithful attention and cooperation.
The department of Food Science and Technology for the 
contribution of "starter" cultures.
Mr. Njonjo, University Farm Manager, for making available 
to us animal  facilities and also to his staFf for their 
assistance.
The project was made possible by the financial support 
from NORAO Research Fund Vote 652/021 and to Professor 
Tjaberg who controlled the vote, I am grateful.
i
Thanks are expressed*to Mrs. Chege for typing this
manuscript.
LIST OF TABLES
PAGE
Table 1: Acceptance criteria for penicillin
3
residues in dairy products
Table 2: Critical penicillin levels in milk
8
for bacteria
Table 3: Inhibitory levels of certain anti-
biotics against starter cultures 9
in inilk
Occurrence of antibiotic residues in milk (tables 4-10):
Table 4: United States of America
12-13
Table 5: Great Britain
A. England and Wales 14
B. Scotland 14-15
C. Northern Ireland 15
Table 6:  Irish Republic
16
Table 7:  Netherlands
17-18
Table 8: Denmark
18-19
Table 9: Australia
i 19-20
»  ♦
Table 10: South Africa
21
(iv)
PAGE
Table 11: Inhibitory substances in milk
61
collected from K.C.C. centres
Table 12: Heating influence on zoning of
•  .,T   62
penicillin
Table 13: pH influence on zone size  52
Table 14: Minimum inhibitory concentrations 
of penicillin and oxytetracycline on  63 
Strept.  lactis and Lact. bulgaricus.
1
y  ♦
(v)
LIST OF FIGURES
PAGE
Fig. 1:
Schematic representation of the distri
butions of a weak acid and a weak base  36 
across the manrmary gland epithelium
o
Fig. 2:
Penicillin concentrations in milk of 
cows injected intramuscularly with 
procaine penicillin G in aqueous sus-  64 
pension (the results given are average 
readings for 6 cows)
Fig. 3:
Penicillin concentrations in milk of 
V
cows injected intramuscularly with 
procaine perucillin G in aqueous
65
suspension (the results given are 
for pooled quarter milk samples:
Cow 1, Cow 2, Cow 3)
Fig. 4:
Penicillin concentrations in milk 
of cows injected intramuscularly 
with procaine penicillin G in
66
aqueous suspension (the results 
given are for pooled quarter milk 
samples: Cow 4, Cow 5, Cow 6) •
•  /
»  ♦
(vi)
PAGE
Fig.  5:
Excretion of penicillin in the milk 
after infusion of Vetramycin CE) -
67
suspension (the results given are 
average readings for 6 cows)
(vii)
LIST OF APPENDICES
Appendix 1 Standard curve for penicillin
Appendix 2 A surrmary of milk sampling in the 
period 1977-1978
Appendix 3: Testing for antibiotic residues 
in milk collected from various 
K.C.C. centres
Appedix 4: Determination of minimum inhi
bitory concentrations of peni
■/ cillin andoxytetracycline 
on Lact. bulgaricus and Strept. 
lactis.
Appendix 5: Concentration and duration of 
detectable levels of penicillin 
in milk following intramuscular 
injection of procaine penicillin 
G (300,000 units/ml) in aqueous 
suspension
Appendix 6: Concentration and duration of
detectable levels of penicillin
in quarter milk samples following 
»  ♦
intramuscular injection of 
procaine penicillin G (300,000 
units/Nl) in aqueous suspension
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