Abstract:
Bioaerosols have been found in the majority of occupational environments,
including poultry processing facilities, animal feeding houses and other meat
processing plants. Due to the notable concentrations of bioaerosols indicated
in such food processing locations, this study set out to investigate the
presence of airborne microorganisms together with related environmental
parameters in six processing areas (receiving/killing, defeathering,
evisceration, air-chilling, packaging and dispatch) in a chicken abattoir. The
aims of the study were to quantify and identify the microbial bioaerosols as
well as to evaluate the influence of the selected environmental parameters
thereon. Samples were collected at different localities as well as over various
time intervals at a Grade-A abattoir situated in the city of Kroonstad, Free
State Province. Microbial analyses were done using a SAS Bioaerosol
Sampler (PBI International, Milan, Italy) through selective culturing procedures
whereas the environmental parameters were analysed using calibrated direct
reading instruments. Statistical analyses were performed using the StatSoft
(Version 7.1) software. Results showed mean counts of 2.2 x 104 cfu.m,3 for Staphylococcus aureus, 2.1 x 104 cfu .m·3 for fungi , 8.8 x 102 cfu.m·3 for total
coliforms and 3.4 x 102 cfu.m-3 for Escherichia coli respectively. Pseudomonas
aeruginosa and Listeria monocytogenes reached 2.4 x 103 cfu.m-3 and 1.7 x
103 cfu.m-3 respectively, and finally, Bacillus cereus and presumptive
Salmonella spp presented counts of 4.0 x 103 cfu.m-3 and 3.5 x 103 cfu.m·3
These counts were without exception with in the infective dose limit and the
legislative guidelines used as reference in this study, although explicit
guidelines for bioaerosols in food processing areas have not yet been set in
South Africa.
Relative humidity showed an average of 71 % at a temperature of 18°C, and
wind velocity and airborne dust particles were recorded as 7 m.s-1 and 3.76
mg.m-3 respectively. The inter-relationships between the bioaerosolised microorganisms
and the environmental parameters were additionally determined
and strong correlations were noted between the occurrence of specifically
Bacillus cereus and airflow, between Pseudomonas aeruginosa and relative
humidity, and between the total coliforms and temperature respectively. Based
on the findings of this study a number of recommendations were made to
industry which include physical separation of the processing sections by
material such as plastic curtaining to minimise the spread of micro-organisms,
control of the environmental parameters that had a significant influence on the
bioaerosols and colour categorisation as a means of representing the extent of
the risk in each location.
