The prevalence of enzyme sensitization in the bakeries was 7.8% when all the employees were taken into account and 11.8% in the bakers' group. The prevalence coincides with those report edelsewhere in Europe, for example, 5-16% in the United Kingdom (Cullinan et al 1994, Smith & Smith 1998, Jeffrey et al 1999,Nieuwenhuijsen et al 1999), 9% in The Netherlands (Houba et al 1996), 7.5% in Italy (DeZotti et al 1994), and 19% in Germany (Baur1998a).

The prevalence of flour sensitization in bakeries was12%, which was on about the same order as elsewhere in Europe in the aforementioned studies (6%-24%). The employees sensitized to enzymes belonged to typical groups exposed to flour and enzymes,but a detailed exposure profile was not included in the original study design. Thus further exposure-response assessment was not possible.It was learned that the job tasks of many of the sensitized workers had varied over the years. The study demonstrated that exposure to powdered additives containing enzymes leads to sensitition in Finnish bakers. In the rye crisp factory, where exposure was less on the whole than in the bakeries, sensitization to enzymes was rare. Cellulase was shown to cause sensitization even at moderate exposure levels. There was a significant association between enzyme sensitization and work-related respiratory symptoms.

However, co-sensitization with flours was common, and the origin of the symptoms was difficult to determine.The animal feed industry is a new area of enzyme application. It was demonstrated that enzymes pose an allergy risk in this industry,too. The risk is smaller than, for example, in the baking industry, but,still, cases of occupational asthma due to enzymes have occurred.There was a correlation between sensitization to enzymes and work-related symptoms, and some of the sensitized workers reported symptoms when exposed to enzymes. One of the enzymes to which sensitization was shown was phytase, which has been developed solely for use in animal feeding. Previously, sensitization to phytase was found in Finnish enzyme production (study II). These were the first reports of allergy caused by this enzyme. In the detergent factory, a surprisingly high prevalence (22%) of symptomatic sensitization was found among the process workers.

In addition to established allergens in the industry, the bacterial proteases, sensitization to new enzymes such as lipase and cellulase was detected. This was the first publication on the allergenity of these enzymes in the detergent industry. Sensitization to bacterial a amylase (Termamyl (r) ) in the industry had been noted since the late 1980s (Sarlo et al 1997). In a later paper from the same multinational detergent company it was also reported that sensitization to lipase had been detected in the early 1990s (Peters et al 2001).

In addition the present study showed that enzyme allergy is still possible, and it can even occur at a high rate, in the detergent industry, despite the use of encapsulated enzyme preparations that are principally considered nondusty and safe. This conclusion received support recently from the study of Cullinan et al (2000) in the United Kingdom. The prevalence of sensitization and clinical allergy in these two studies was in clear contrast to the prevalences reported by large multinational companies (Cathcart et al 1997, Schweigert et al 2000, Peters et al 2001). Obviously there are large variations in industrial hygiene conditions between different plants.

Small industries may find it economically difficult to meet all the standards of the industrial hygiene programs conducted in large companies, including periodic health checks and continuous monitoring of workplace air by immunoassays (Schweigert et al 2000,Nicholson et al 2001). In the enzyme-producing industry, a high rate of sensitization, up to 25%, was noted in subgroups with high levels of exposure.

The division into subgroups enabled exposure-response (sensitization and respiratory symptoms) calculations, and a statistically significant trend was found for both sensitization and symptoms. A unique feature was the high allergy risk of the laboratory personnel. It turned out that powdered enzymes had been handled rather carelessly, and, clearly, an awareness of the sensitizing properties of the cellulolytic enzymes was lacking.

In addition to the sensitization of the employees who handled enzymes themselves or worked in the vicinity of enzyme handling, some cases of sensitization were found among people not involved directly in production, for example, among the cleaning and maintenance personnel and also among office personnel with occasional exposure. Maintenance workers may be exposed to the highest peak concentrations of enzymes in the workplace. The practice of hiring personnel on a subcontract basis is becoming general, and this practice increases the probability of being exposed to enzymes. The experiences gained in the subcontract plant that spray-dried cellulase confirmed the importance of proper and sufficient information. The employees in the subcontract plant were clearly ignorant about the sensitizing properties of the substances they were handling.