Microbial contamination level and microbial diversity of occupational environment in commercial and traditional dairy plants

• Main Authors: Agata Stobnicka-Kupiec, Małgorzata Gołofit-Szymczak, Rafał Górny
• Format: Article
• Language: English
• Published: Institute of Rural Health 2019-12-01
• Series: Annals of Agricultural and Environmental Medicine
• Subjects: occupational exposure; bacteria; fungi; bioaerosols; surface swabs; dairy plants
• Online Access: http://www.journalssystem.com/aaem/Microbial-contamination-level-and-microbial-diversity-of-occupational-environment,112381,0,2.html

Objective The aim of this study was to assess microbial contamination of the air and surfaces at workplaces in commercial (CD) and traditional (TD) dairies. Material and methods Bioaerosol (impactor) and surface (swab) samples were collected in CD and in TD. Bacterial and fungal concentrations in the air and on surfaces were calculated and all isolated microorganisms taxonomically identified, based on their morphological, biochemical and molecular features. Results Average concentrations of bacterial aerosol ranged between 70–860 CFU/m 3 and 265–14639 CFU/m 3 , while for fungal aerosol were between 50–290 CFU/m 3 and 55–480 CFU/m 3 in CD and TD, respectively. Average bacterial concentrations on surfaces ranged between 1.0–49.7 CFU/cm 2 and 0.2–60.4 CFU/cm 2 , whereas average fungal surface contamination ranged between 0–2.7 CFU/cm 2 and 0–4.6 CFU/cm 2 in CD and TD, respectively. Qualitative analysis revealed mainly the presence of saprophytic microorganisms; however, several pathogenic strains (Staphylococcus aureus, Streptococcus intermedius, Clostridium perfringens, Actinomyces spp., Streptomyces spp., Candida albicans) were also isolated from both the air and surface samples in the studied dairies. Conclusions The air and surfaces in TD were more polluted than those in CD; however, in both types of dairies, the levels of microbial contaminants did not exceed respective threshold limit values. Nevertheless, the presence of pathogenic microorganisms may increase health risk for dairy workers and influence the quality of products. Hence, proper hygienic measures should be introduced and performed to guarantee high microbial quality of both production processes and milk products.