Wh. Heeschen et J. Reichmuth, MASTITIS - THE DISEASE UNDER ASPECTS OF MILK QUALITY AND HYGIENE, Kieler Milchwirtschaftliche Forschungsberichte, 47(3), 1995, pp. 221-237
1. Inflammatory changes in the mammary gland influence the process of
milk synthesis both quantitatively and qualitatively. The changes in t
he constituents of milk affect the major components (lactose, fat, pro
teins) as well as fatty acids, protein fractions, caseins, wh ey prote
ins, anions and cations, conductivity, enzymes etc. With increasing nu
mbers of somatic cells the growth of starter cultures in the milk may
be adversely influenced. Renneting time and heat stability of the milk
can be impaired. 2. The hygienic value of raw milk is determined by p
athogenic microorganisms, saprophytic microorganisms, residues and con
taminants. In the case of mastitis pathogenic microorganisms may occur
, which are infectious also for men (e.g. B-streptococci, Escherichia
coli strains) or which form under certain circumstances toxins (e.g. S
taphylococcus aureus, Escherichia coli). 3. Residues due to the treatm
ent of mastitis include primarily antimicrobials like antibiotics and
sulfa drugs. The significance of antibiotic residues in milk has to be
discussed under two important aspects: that relating to payment of mi
lk on the basis of the technological quality (''inhibitors'') and that
relating to public health and governed by food laws. 4. Concerning th
e eff ect of antibiotic residues on human health a number of aspects h
as to be considered (toxicological, microbiological and immunopatholog
ical effects). From a technological point of view the sensitivity of t
hermophilic and mesophilic starters to different antibiotics may vary
widely. The fixation of maximum residue limits (MRLs) for a number of
antimicrobials has led to the difficulty that a negative result of so-
called inhibitor tests does not neccessarily indicate concentrations o
f antimicrobials below the MRLs. A new and integrated system for the d
etection of antimicrobials has to be developed, which takes technologi
cal and toxicological aspects into Concern. 5. The use of disinfectant
s for the dipping of teats before and after milking must also critical
ly be evaluated. Not only the active ingredients (iodine, chlorhexidin
e, chlorine etc.) have to be taken into consideration, but also other
components used (e.g. detergents, additives). 6. The number of somatic
cells in milk is an indicator of its qualitative/hygienic properties,
which case reflect the given mastitis situation in the herd. The obje
ctives of mastitis control measures should primarily cover the supply
of milk with a low somatic cell content, which meets the qualitative a
nd hygienic expectations of manufacturers and consumers.