Several studies have indicated the existence of a high prevalence (up to 68%) of chronic bronchitis among workers involved in pork-breeding; isolated cases of asthma and allergic alveolitis have also been reported. Pork-breeding is the second largest agricultural sector in Québec, employing approximately 15 000 people. Although the working conditions in Québec pork-breeding operations have not been studied, it is generally accepted that they are characterized by the presence of multiple species of microorganisms, various antigenic substances (feed, pig hair and skin, etc.), and a number of toxic gases, including hydrogen sulphide, ammonia, carbon dioxide, and carbon monoxide. At the request of a pneumologist at l'Hôpital Laval in Québec, the IRSST sampled the ambient air of four pork-breeding facilities and characterized the microflora found there. The goals of the project were the characterization of the microflora and the factors on which their growth depends, and the evaluation of the feasibility of implementing engineering control measures and personal protective strategies. The most commonly encountered species of microflora were identified and quantified, sampling methods developed, and a guide for the evaluation of exposure to microflora distributed to pork breeders and those responsible for occupational health and safety.
