Trends in Foodborne Outbreaks, Los Angeles County, California, 2004-2013, with Focused Investigation on Comparison of Contributing Factors in "Dine-in" versus "Take-out" Settings of Food Consumption Open Access

O'Leary, Erin Nicole (2015)

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Background: Analyzing trends in foodborne disease outbreaks is an important means of identifying risk factors and how risk has changed over time. In order to create prevention programs regarding food safety it is essential to determine whether risks differ in various settings of food consumption. This paper aims to identify where risks of foodborne outbreaks lie by summarizing trends in outbreaks occurring in Los Angeles County between 2004 and 2013 and by assessing the association between "dine-in" and "take-out" settings of food consumption.

Methods: Data on foodborne outbreaks occurring in Los Angeles County, 2004 to 2013 were obtained from county outbreaks reports. Patterns in number of outbreaks reported per year, number of illnesses per outbreak, etiologic agents, food items implicated, setting of outbreak, and laboratory confirmation change over time were summarized, taking into account changes in reporting systems. The association was examined between contributing factors relating to contamination, proliferation, and survival in outbreaks occurring in "dine-in" and "take-out" settings of food consumption.

Results: There was a statistically significant decline in the number of outbreaks reported in Los Angeles County between 2004 and 2013, though when taking into account changes in the National Outbreak Reporting System occurring in 2009, this trend was not significant. There was a statistically significant decrease in the number of illness over the 10-years, and a decline in the number of foodborne outbreaks occurring in private residences between 2009 and 2013. Controlling for food items implicated, there was an association between contamination factors contributing to outbreaks occurring in "take-out" settings (OR=2.56, p=0.06) and an association between proliferation (OR=2.67, p=0.09) and survival factors (OR=2.41, p=0.21) contributing to outbreaks occurring in "dine-in" settings.

Conclusion: Risk of foodborne outbreaks was highest in restaurants, workplaces, and private residences, and was most often attributed to dishes, vegetables, and poultry. These data suggest that further efforts are needed to improve food safety in these particular areas of concern. By providing associations between contributing factors and settings of food consumption, programs can target specific settings based on risk factors identified.

Table of Contents


Introduction 1

Background 5

Expanded Methods 13

CHAPTER 2: Manuscript

Title, Authors, Abstract 19

Introduction 19

Methods 23

Results 30

Discussion 33

References 43

Tables 46

Figures 50


Summary 53

Public Health Implications 53

Possible Future Directions 54

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