A survey of the bioaerosol composition and related environmental parameters in a high-throughput chicken processing facility

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.