Changes in microbial ecology during poultry production
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Date
2000-03
Authors
Schreuder, Johanna Catharina
Journal Title
Journal ISSN
Volume Title
Publisher
University of the Free State
Abstract
Microorganisms, especially pathogens, play an important role in the deterioration
of poultry meat and its products causing spoilage or food poisoning. The meat
renders an ideal medium for the growth and progression of microorganisms
originating from the environment on the farm (eggs and broiler), transport to the
abattoir as well as the abattoir. As far as we know, no attempts were undertaken
to determine the total microbial spectrum, including bacterial and yeast
populations from the egg unto the chicken carcass after slaughtering. A historical
review of the incidence and extent of microorganisms associated with poultry
and it's environment is given in Chapter 1. The background of poultry
production and contribution of microorganisms (for example pathogens and
yeasts) are highlighted. In Chapter 2 a survey was undertaken to determine the incidence, extent and
serotypes of different pathogens on and in freshly laid eggs as well as incubated
eggs in the breeder broiler hatchery. In addition, the number of viable cells of
bacteria and yeasts were also determined. Microbial counts on the dirty eggs
predominated. A major decline in microbial numbers on the egg shells, however,
were observed after 18 days in the incubator. The deduction in bacterial
populations present on the egg shells after 18 days in the incubator, is ascribed to
the constant fogging of the environment inside the incubator with clinafarm. The
irregular gathering of eggs as well as the dirty hands of the egg collectors could
have been the major contributors of the high counts on these eggs. The only
pathogens obtained were Listeria and E. coli type 1.In Chapter 3 the microbial populations associated with the caecum and liver of
broilers as well as with the environment were determined. Anaerobic plate counts
reflecting the dominance of bacterial populations were constantly the highest
ascribed to the contents of the gut. Salmonella, Staphylococcus aureus and E. coli
type 1 were isolated from the caecum, however no Listeria were isolated.
Salmonella and E. coli type 1 were isolated from the liver. The high incidence of
pathogens associated with the broilers is an indication of the pathogens that enter
the abattoir. These levels of pathogens, further increased during transport to the
abattoir.In Chapter 4 the incidence and extent of microbial populations associated with
broiler meat and the environment in the abattoir were evaluated. All the
pathogens present on the farm were also observed in the abattoir. The main
reasons for the similarity in the incidence of pathogens on the farm and the
abattoir were ascribed to the transport from the farm to the abattoir, the process
of slaughtering, equipment surfaces in the abattoir and people handling the meat.
Aerobic plate counts predominated on the neckskin samples, equipment surfaces
as well as in the water and air of the abattoir. E. coli type 1 clearly predominated
on the neckskin samples as well as on the equipment surfaces, followed by
Staphylococcus (U/reus and that by Salmonella. No Listeria isolates was,
however, isolated from either the broiler farm or the abattoir, but was indeed
observed on the egg shells from the breeder farm. Although a pattern reflecting the incidence of pathogens could be establish
between the broiler farm and the abattoir, no comparison could be made with the
eggs from the breeder farm and hatchery. This may be blamed on the sampling of
insufficient number of eggs, or the lack of multiple repetitions. Despite the
inability to detect the primary sources of pathogens the distinct possibility
remained that the broiler farm was the main contributor towards microbial
contamination and infection. Therefore, more effort is needed to control the diseases and infections on broiler
farms, because in an abattoir you only get out what you put in.
Description
Keywords
Food -- Microbiology, Food spoilage, Dissertation (M.Sc. (Microbiology and Biochemistry))--University of the Free State, 2000