Outbreaks of Shigella sonnei infection associated with eating fresh parsley--United States and Canada, July-August 1998.
In August 1998, the Minnesota Department of Health reported to CDC two restaurant-associated outbreaks of Shigella sonnei infections. Isolates from both outbreaks had two closely related pulsed-field gel electrophoresis (PFGE) patterns that differed only by a single band. Epidemiologic investigations implicated chopped, uncooked, curly parsley as the common vehicle for these outbreaks. Through inquiries to health departments and public health laboratories, six similar outbreaks were identified during July-August (in California [two], Massachusetts, and Florida in the United States and in Ontario and Alberta in Canada). Isolates from five of these outbreaks had the same PFGE pattern identified in the two outbreaks in Minnesota. This report describes the epidemiologic, traceback, environmental, and laboratory investigations, which implicated parsley imported from a farm in Mexico as the source of these outbreaks. (+info)
Evaluation of dehydrated restaurant food waste products as feedstuffs for finishing pigs.
Two dehydrated restaurant food waste (DFW) products were evaluated as potential feedstuffs for finishing pigs. For each product, fresh food wastes were obtained from food service operations at a resort complex in central Florida. The wastes were mostly leftover food and plate scrapings. The wastes were minced, blended with a feed stock (soy hulls and wheat flour [DFW1] or soy hulls and ground corn [DFW2]), pelleted, and dried. The dried product was then blended with additional minced fresh food wastes and dried; this process was then repeated. The final DFW products contained approximately 60% dried food wastes. The DFW1 and DFW2 products contained 11.4 and 8.4% moisture, 15.0 and 14.4% CP, 13.8 and 16.0% crude fat, 10.4 and 14.5% crude fiber, 5.8 and 4.7% ash, .63 and .64% lysine, .54 and .63% Ca, .34 and .38% P, .69 and .86% Cl, and .35 and .47% Na, respectively. Two feeding trials with 48 and 72 finishing pigs (56 to 112 kg), respectively, were conducted comparing diets without (control) or with the DFW product included at 40% of the diet (DFW1) for Trial 1 and 40 or 80% of the diet (DFW2) for Trial 2. Pigs fed the DFW diets in both trials had ADG that were similar (P > . 10) to and average gain:feed ratios that were superior (P = .06, Trial 1; P < .01; linear, Trial 2) to those for control pigs. Carcass lean content and lean quality scores were not reduced (P > . 10) by feeding pigs the DFW diets in either trial. Carcass fat became softer (P < .01; linear) with increasing amount of DFW2 in the diet in Trial 2. Thus, dehydrated restaurant food wastes have the potential to produce a nutritious feedstuff for pigs while offering a viable solid waste disposal option. (+info)
Exposure of U.S. workers to environmental tobacco smoke.
The concentrations of environmental tobacco smoke (ETS) to which workers are exposed have been measured, using nicotine or other tracers, in diverse workplaces. Policies restricting workplace smoking to a few designated areas have been shown to reduce concentrations of ETS, although the effectiveness of such policies varies among work sites. Policies that ban smoking in the workplace are the most effective and generally lower all nicotine concentrations to less than 1 microg/m3; by contrast, mean concentrations measured in workplaces that allow smoking generally range from 2 to 6 microg/m3 in offices, from 3 to 8 microg/m3 in restaurants, and from 1 to 6 microg/m3 in the workplaces of blue-collar workers. Mean nicotine concentrations from 1 to 3 microg/m3 have been measured in the homes of smokers. Furthermore, workplace concentrations are highly variable, and some concentrations are more than 10 times higher than the average home levels, which have been established to cause lung cancer, heart disease, and other adverse health effects. For the approximately 30% of workers exposed to ETS in the workplace but not in the home, workplace exposure is the principal source of ETS. Among those with home exposures, exposures at work may exceed those resulting from home. We conclude that a significant number of U.S. workers are exposed to hazardous levels of ETS. (+info)
Occupational exposure to environmental tobacco smoke: results of two personal exposure studies.
Personal monitoring is a more accurate measure of individual exposure to airborne constituents because it incorporates human activity patterns and collects actual breathing zone samples to which subjects are exposed. Two recent studies conducted by our laboratory offer perspective on occupational exposure to environmental tobacco smoke (ETS) from a personal exposure standpoint. In a study of nearly 1600 workers, levels of ETS were lower than or comparable to those in earlier studies. Limits on smoking in designated areas also acted to reduce overall exposure of workers. In facilities where smoking is permitted, ETS exposures are 10 to 20 times greater than in facilities in which smoking is banned. Service workers were exposed to higher levels of ETS than workers in white-collar occupations. For the narrower occupational category of waiters, waitresses, and bartenders, a second study in one urban location indicated that ETS levels to which wait staff are exposed are not considerably different from those exposure levels of subjects in the larger study who work in environments in which smoking is unrestricted. Bartenders were exposed to higher ETS levels, but there is a distinction between bartenders working in smaller facilities and those working in multiroom restaurant bars, with the former exposed to higher levels of ETS than the latter. In addition, ETS levels encountered by these more highly exposed workers are lower that those estimated by the Occupational Safety and Health Administration. Concomitant area monitoring in the smaller study suggests that area samples can only be used to estimate individual personal exposure to within an order of magnitude or greater. (+info)
Validity of the uniform mixing assumption: determining human exposure to environmental tobacco smoke.
When using the mass balance equation to model indoor air quality, the primary assumption is that of uniform mixing. Different points in a single compartment are assumed to have the same instantaneous pollutant concentrations as all other points. Although such an assumption may be unrealistic, under certain conditions predictions (or measurements) of exposures at single points in a room are still within acceptable limits of error (e.g., 10%). In this article, three studies of the mixing of environmental tobacco smoke (ETS) pollutants are reviewed, and data from several other ETS field studies are presented. Under typical conditions for both short sources (e.g., 10 min) and the continuous sources of ETS in smoking lounges, I find that average exposure concentrations for a single point in a room represent the average exposure across all points in the room within 10% for averaging times ranging from 12 to 80 min. I present a method for determining theoretical estimates of acceptable averaging times for a continuous point source. (+info)
An introduction to the indirect exposure assessment approach: modeling human exposure using microenvironmental measurements and the recent National Human Activity Pattern Survey.
Indirect exposure approaches offer a feasible and accurate method for estimating population exposures to indoor pollutants, including environmental tobacco smoke (ETS). In an effort to make the indirect exposure assessment approach more accessible to people in the health and risk assessment fields, this paper provides examples using real data from (italic>a(/italic>) a week-long personal carbon monoxide monitoring survey conducted by the author; and (italic>b(/italic>) the 1992 to 1994 National Human Activity Pattern Survey (NHAPS) for the United States. The indirect approach uses measurements of exposures in specific microenvironments (e.g., homes, bars, offices), validated microenvironmental models (based on the mass balance equation), and human activity pattern data obtained from questionnaires to predict frequency distributions of exposure for entire populations. This approach requires fewer resources than the direct approach to exposure assessment, for which the distribution of monitors to a representative sample of a given population is necessary. In the indirect exposure assessment approach, average microenvironmental concentrations are multiplied by the total time spent in each microenvironment to give total integrated exposure. By assuming that the concentrations encountered in each of 10 location categories are the same for different members of the U.S. population (i.e., the NHAPS respondents), the hypothetical contribution that ETS makes to the average 24-hr respirable suspended particle exposure for Americans working their main job is calculated in this paper to be 18 microg/m3. This article is an illustrative review and does not contain an actual exposure assessment or model validation. (+info)
A Mexican restaurant-associated outbreak of Salmonella Enteritidis type 34 infections traced to a contaminated egg farm.
In May 1996, the Georgia Division of Public Health was notified about a cluster of persons with Salmonella Enteritidis (SE) infections in Waycross, Georgia. A matched pair case-control study to determine risk factors for illness found a statistically significant association of SE infection with a history of having eaten at Restaurant A during the 5 days before onset of illness (relative risk = 13 [95% confidence interval (CI) = 3-62, P < 0.01]). In a second case-control study, to determine specific food exposures, consumption of a deep-fried Mexican dish (chile relleno) (4 of 21 cases vs. 0 of 26 controls, odds ratio undefined, 95% CI > 1.46, P = 0.034) was found to be significantly associated with SE infection. An environmental investigation found evidence of suboptimal food storage and cooking temperatures at Restaurant A; cross contamination of foods may have contributed to the low attributable risk identified for chile rellenos. Five of 37 Restaurant A food and environment specimens yielded SE strains. All five positive specimens were from chiles rellenos. Of the seven outbreak-associated strains (six patient isolates and one food isolate from Restaurant A) for which phage typing was conducted, all were phage type 34. A FDA traceback investigation through Restaurant A's single-egg supplier identified the potential source as three interrelated farms in South Carolina. Environmental culture from one of these farms yielded SE phage type 34. As a result of this outbreak, FDA helped institute a statewide egg quality-assurance programme in South Carolina to minimize SE contamination of eggs. (+info)
An untypeable Shigella flexneri strain associated with an outbreak in California.
Eleven Shigella flexneri (group B) isolates were recovered from epidemiologically linked patrons and food handlers from a restaurant-associated outbreak of shigellosis. Six isolates available for pulsed-field gel electrophoresis were identical. All strains agglutinated in group B and subgroup factor 6 sera but not in group 1 through group 6 sera. (+info)