Trends in Salmonella Infantis human illness incidence and chicken carcass prevalence in the United States; 1996-2019.

The incidence of human illness due to Salmonella Infantis reported to Foodborne Diseases Active Surveillance Network and the prevalence of Infantis on chicken carcasses reported by the United States Department of Agriculture Food Safety and Inspection Service have increased significantly in the past decade. However, the trends do not appear coincident, as would be expected if the increased prevalence in chicken led to the increase in the incidence of human illness. Salmonella Infantis incidence and prevalence trends are analyzed using penalized B-spline methods for generalized additive regression models. The association between the two time series is analyzed using time-lagged rank-order cross-correlation. Geographic variations in reported incidence and trends are also explored. The increase in human incidence of Salmonella Infantis began circa 2011. The increase in chicken carcass prevalence began circa 2015. A 4-year lag on chicken carcass prevalence maximizes the rank-order cross-correlation with the incidence of illness. While chicken consumption undoubtedly contributes to the incidence of human illness due to Salmonella Infantis, the initial increase in reported illness was likely due to one or more other transmission pathways. Other potential transmission pathways include non-chicken foodborne, waterborne, person-to-person, animal contact, and environmental.

Depression screening in patients with vascular disease.

OBJECTIVES: Major depression is associated with increased morbidity and mortality in vascular surgery patients. The US Preventive Services Task Force and American Heart Association recommend routine depression screening for adults, especially those with cardiovascular disease. Since routine depression screening has not been implemented in most vascular surgery clinics across the nation, we sought to determine the feasibility of depression screening and understand the prevalence and predictors of depression in patients presenting to a single institution's vascular surgery clinic over a 4 month period. METHODS: From June to September 2020, vascular surgery clinic patients were administered a 26-item survey that included validated scales for depression (PHQ-9), pain, frailty, alcohol dependence, and nicotine dependence. Although not validated, the Rosenberg Self-Esteem Scale was also administered. Patient charts were reviewed for demographic information and medical history. 9-digit patient zip codes were used to determine Area Deprivation Index, a measure of socioeconomic status. Univariate and multivariate analyses were performed to understand the factors associated with increased depression prevalence in the study population. RESULTS: A total of 140 (36.4%) of 385 patients met study inclusion criteria. 35.7% of them screened positive for mild to severe depression (PHQ-9 scores ≥5). On univariate analysis, major depression was significantly associated with lower socioeconomic status (p = 0.007), higher frailty (p < 0.001), lower self-esteem (p < 0.001), higher daily pain (p < 0.001), health problems that interfere with social activities (p < 0.001), fatigue (p < 0.001), unmarried status (p = 0.031), and lack of primary care provider (p = 0.048). Multivariate analyses significantly predicted higher frailty (B= 0.487, p = 0.007) and lower self-esteem (B= -0.413, p < 0.001) in patients with depression. Depression was not associated with gender, age, employment status, smoking status, alcohol use, or type of vascular disease. COCLUSIONS: More than one-third of vascular surgery clinic patients have comorbid depression. Higher frailty and lower self-esteem are significant risk factors for depression. Prevention and early identification of frailty may improve outcomes. Depression screening in vascular surgery clinics is feasible and could be useful in determining which patients may benefit from more frequent follow-up and monitoring for associated comorbidities. Vascular surgeons may play an important role in screening for depression and referring patients for psychotherapy and/or pharmacotherapy.

Impact of discrimination and coping on Veterans' willingness to seek treatment for physical and mental health problems.

OBJECTIVE: This study aimed to provide insight into health disparities among Veterans by (a) documenting the prevalence of physical and mental health problems in a racially diverse sample of Veterans, (b) comparing Veterans' willingness to seek treatment for various physical and mental health conditions, and (c) examining the impact of discrimination and coping on willingness to seek treatment. METHOD: Veterans reported on current physical and mental health symptoms and the importance of treatment for various health conditions. Patterns were examined in the full sample (N = 334, 32% female) and the subsample who reported hazardous alcohol use in the past year (n = 116, 33% female). Linear regression was used to test alternative coping as a moderator of the association between experiences with discrimination and willingness to seek treatment among Veterans of color (n = 242, 37% female). RESULTS: Participants reported greater willingness to seek treatment for physical than mental health conditions. Sleep problems (75%) and substance use (74%) were the most prevalent health behaviors, but they were rated lowest in treatment importance. Among Veterans of color, everyday experiences with discrimination were generally associated with less willingness to seek physical or mental health treatment, but often only among those who denied use of coping strategies. CONCLUSIONS: Veterans are least willing to seek treatment for the health conditions that are most prevalent in their communities. Coping strategies may mitigate the negative association between discriminatory experiences and willingness to seek treatment among Veterans of color. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

A Survey of Vascular Surgery Program Directors: Perspectives following USMLE Step 1 Conversion to Pass/Fail and Virtual Only Interviews.

BACKGROUND: Step 1 of the United States Medical Licensing Examination (USMLE), a historically important factor in the selection of vascular surgery residents and fellows, transitioned to completely pass/fail on January 26, 2022. Due to the COVID-19 pandemic, residency and fellowship interviews were conducted virtually during the 2020-21 and 2021-22 application cycles. Given these significant changes in the evaluation of candidates for residency training, we sought to understand vascular surgery program directors' (PDs) perspectives regarding the change in step 1 scoring and use of virtual interviews as well as determine which factors will assume importance when applying to vascular surgery training programs in the future. METHODS: A 26-item survey questionnaire was created using Qualtrics survey tools with questions regarding attitudes toward the change in step 1 scoring and virtual interviews, the importance of additional factors utilized by programs in selecting candidates for interviews and ranking applicants for residency/fellowship selection, and programmatic demographics. This was distributed anonymously to all vascular surgery training programs over a 2-week period using a comprehensive list of 249 unique email addresses created by cross-referencing the Accreditation Council for Graduate Medical Education list of certified vascular training programs with email addresses from individual program websites identifying current program leadership. Responses were analyzed with descriptive statistics with values listed as average Likert scale weight ± standard deviation (SD) or percentages. RESULTS: Sixty-eight of 249 (27.3%) program and associate PDs responded to the survey. Of which, 33.9% of respondents strongly disagreed with step 1 going completely pass/fail. In the absence of a scored USMLE step 1, letters of recommendation (average Likert scale weight ± SD, 4.43 ± 0.92), dedication to specialty (4.14 ± 1.03), and USMLE step 2 CK (4.06 ± 0.92) had the highest average scores for deciding which applicants to interview for integrated vascular surgery residency. For determining which candidates to interview for vascular surgery fellowship, letters of recommendation (4.51 ± 0.84), dedication to specialty (4.12 ± 0.90), and research (4.10 ± 0.80) had the highest average scores. For ranking residency candidates, the interviewee's perceived "fit" (4.61 ± 0.55), letters of recommendation (4.53 ± 0.76), and an overall interview experience (4.47 ± 0.62) had the highest average scores. Similarly, the factors with the highest average Likert scores for ranking fellowship candidates included the interviewee's perceived "fit" (4.69 ± 0.51), letters of recommendation (4.65 ± 0.52), and an overall interview experience (4.51 ± 0.59). The majority (72.2%) of PDs preferred in-person interviews; however, 50% of respondents were at least "somewhat satisfied" with virtual interviews during the 2021-22 application cycle as they could judge applicants' interview skills at least "moderately well." The minority (18.8%) who preferred virtual interviews most commonly noted a "reduction of the financial burden for applicants" as the reason for this preference. CONCLUSIONS: Most vascular surgery program and associate PDs were dissatisfied with USMLE step 1 going pass/fail with most indicating prescreening applicants using both step 1 and step 2 clinical knowledge (CK) during the residency and fellowship selection processes. In the absence of a scored step 1, the top factors for interviewing and ranking integrated vascular surgery residency and fellowship candidates included letters of recommendation, dedication to specialty, research, USMLE step 2 CK, the interviewee's perceived "fit," and overall interview experience. Though most PDs preferred face-to-face interviews, they were overall at least "somewhat satisfied" with the virtual format that took place during the 2021-22 cycle.

Prevalence and correlates of alcohol-induced blackout in a diverse sample of veterans.

BACKGROUND: Alcohol-induced blackouts have been associated concurrently and prospectively with alcohol-related harm. Although rates of heavy drinking among military samples tend to be comparable or higher than rates among civilian samples, the prevalence and correlates of blackout in the military population are understudied. METHODS: Veterans (N = 241, 29% female, 39% Black) reported on their alcohol consumption and mental health as part of a larger health-related study among veterans. In this secondary analysis, we tested theoretically and empirically informed predictors (gender, drinking quantity, and other drug use) and consequences [depression, posttraumatic stress disorder (PTSD)] of alcohol-induced blackout. Given the diversity of the sample, potential roles of racial/ethnic discrimination and drinking to cope in alcohol-induced blackout were also tested. RESULTS: Past-year prevalence of alcohol-induced blackout was 53% among veterans who drank alcohol and 68% among those who screened positive for hazardous drinking. Everyday experience of racial discrimination was the strongest concurrent predictor of alcohol-induced blackout. Drinking quantity and use of other drugs were significant correlates only in bivariate models. Controlling for gender, race, drinking quantity, other drug use, and discrimination, blackout frequency was significantly associated with symptoms of depression, but not symptoms of PTSD. Both blackout and racial discrimination were associated with drinking to cope. CONCLUSIONS: The prevalence and correlates of alcohol-induced blackout among veterans are largely consistent with those documented in civilian and young adult populations. Among racially diverse groups, racial discrimination may be more strongly associated with mental health symptoms than alcohol consumption or acute alcohol consequences such as blackout.

Assessing the effectiveness of performance standards for Salmonella contamination of chicken parts.

The United States Department of Agriculture's Food Safety and Inspection Service implemented Salmonella performance standards for establishments producing chicken parts in 2016. The standards were chosen based on the assumption that a 30 % reduction in the occurrence of Salmonella-contaminated chicken parts samples (i.e., legs, breasts or wings) would result following implementation of the performance standard program. The derivation of the performance standards was based on data collected prior to the implementation of the standards and in the intervening years, so overall changes in the Salmonella contamination of this product can be assessed. This study presents a historical review of changes in Salmonella contamination on chicken parts as these changes relate to the performance standard. The analysis demonstrates that the reduction in Salmonella contaminated chicken parts samples was more than 75 %, so the FSIS risk assessment significantly underestimated the actual reduction in Salmonella contamination. An analysis of chicken parts samples collected at retail demonstrates reductions of a similar magnitude. Changes in the characteristics of Salmonella contamination that are potentially relevant to the occurrence or severity of human illness, such as seasonal changes in contamination, the composition of serotypes and changes in antimicrobial resistance, are also assessed. Small but significant seasonal increases in contamination were observed, with the peaks occurring in late winter rather than the more traditional late summer peak. Rapid changes in both the five most common serotypes and antimicrobial resistance patterns were also observed.

Temporal changes in the proportion of Salmonella outbreaks associated with 12 food commodity groups in the United States.

Using data from 20 years of Salmonella foodborne outbreaks, this study investigates significant trends in the proportion of outbreaks associated with 12 broad commodity groups. Outbreak counts are demonstrated to have a stronger trend signal than outbreak illness counts. The number of outbreaks with an identified food vehicle increased significantly between 1998 and 2000. This was followed by a 10-year period when the number of outbreaks decreased. The number of outbreaks increased significantly between 2010 and 2014 and then remained unchanged for the remainder of the study period. During the period of 1998 through 2017, the proportion of outbreaks for three commodities groups, consisting of eggs, pork and seeded vegetables, changed significantly. No significant changes were observed in the remaining nine commodity groups. Simple approximations are derived to highlight the effect of dependencies between outbreak proportions and a consumption analysis for meat and poultry is used to enhance the limited interpretability of the changes in these proportions. Given commodity-specific approaches to verifying food safety and promoting pathogen reduction, regulatory agencies benefit from analyses that elucidate illness trends attributable to the products under their jurisdiction. Results from this trend analysis can be used to inform the development and assessment of new pathogen reduction programmes in the United States.

Motives for and Barriers to Research Participation Among Racially and Ethnically Diverse Veterans.

INTRODUCTION: Veterans in general-and especially those who identify as Veterans of color-are underrepresented in health-related treatment research. This contributes to health inequity by hindering the development of evidence-based treatment recommendations for people of color. This project utilized culturally centered research procedures to identify health-related research priorities and examine motives for and barriers to research participation in a diverse sample of Veterans. MATERIALS AND METHODS: Veterans (N = 330, 32% female; 36% Black, 28% White, 15% Latinx, 12% Asian, 4% Multiracial) reported their experiences with and perspectives on health-related research online from remote locations. Linear regression was used to test associations between discrimination and motives/barriers for research. All procedures were approved by the Institutional Review Board (#2033562). RESULTS: Participants identified psychological concerns, particularly PTSD, as research priorities for Veterans in their communities, but also prioritized physical problems (e.g., brain injury) and social concerns (e.g., homelessness, access to care). Perceptions of, motives for, and barriers to research were similar across racial/ethnic groups. The most common motive was contributing to research that seems important, and the most common barrier was not knowing about research opportunities. Every-day experiences with discrimination (e.g., people acting as if they are afraid of you because of your race/ethnicity) were associated with more barriers to research among Black participants. CONCLUSIONS: Experiences of racial/ethnic discrimination are associated with different research-related outcomes across racial/ethnic groups. Efforts to engage diverse populations should prioritize access to (not willingness to participate in) health-related research.

A quantitative risk metric to support individual sanitary measure reviews in international trade.

In order for the United States Department of Agriculture's (USDA) Food Safety and Inspection Service (FSIS) to make an equivalence determination for a foreign meat, poultry or egg products inspection procedure that differs from FSIS inspection procedures (an Individual Sanitary Measure or ISM), a country must demonstrate objectively that its food safety inspection system provides the same level of public health protection as the FSIS inspection system. To evaluate microbiological testing data that such countries may submit to this end, we present a possible risk metric to inform FSIS's assessment of whether products produced under an alternative inspection system in another country pose no greater consumer risk of foodborne illness than products produced under FSIS inspection. This metric requires evaluation of prevalence estimates of pathogen occurrence in products for the foreign country and the U.S. and determining what constitutes an unacceptable deviance of another country's prevalence from the U.S. prevalence, i.e., the margin of equivalence. We define the margin of equivalence as a multiple of the standard error of the U.S. prevalence estimate. Minimizing the margin of equivalence ensures the maximum public health protection for U.S. consumers, but an optimum choice must also avoid undue burden for quantitative data from alternative inspection systems in the foreign country. Across a wide range of U.S. prevalence levels and sample sizes, we determine margin of equivalence values that provide high confidence in conclusions as to whether or not the country's product poses no greater risk of foodborne illness from microbiological pathogens. These margins of equivalence can be used to inform FSIS's equivalence determination for an ISM request from a foreign country. Illustrative examples are used to support this definition of margin of equivalence. This approach is consistent with the World Trade Organization's concept of risk equivalence and is transparent and practical to apply in situations when FSIS makes an equivalence determination for an ISM requested by a foreign country.

Outcomes after endovascular reintervention for aortic interventions.

OBJECTIVE: Endovascular reinterventions are often performed after previous open or endovascular aortic procedures. We used the GREAT (Global Registry for Endovascular Aortic Treatment) database to compare the outcomes between these groups. We also compared reintervention of any type with a group of patients who had undergone primary endovascular abdominal aortic aneurysm repair (EVAR). METHODS: All patients enrolled in GREAT were grouped according to a previous EVAR or open abdominal aortic procedure (OAP). Univariate analysis was performed using the χ2, Wilcoxon rank sum, and Fisher exact tests. Cox proportional analysis was used to test the predictors for all-cause and aorta-related mortality. RESULTS: A total of 3974 subjects who had undergone EVAR with follow-up data available were included in the GREAT. Of the 3974 procedures, 196 (4.9%) were reinterventions (49 after OAP and 147 after previous EVAR). Reintervention after previous EVAR showed a trend toward a greater endoleak rate through 2 years (13.6% vs 4.1%; P = .07), although no difference was found in the occurrence of the intervention (12.2% vs 17.7%; P = .37). Reintervention after OAP resulted in higher all-cause mortality through 2 years of follow-up (32.7% vs 17.7%; P = .0.03). The predictors of mortality included prior OAP, renal insufficiency, and the use of cutdown for access. Compared with the patients who had undergone primary endovascular repair, patients in the reintervention cohort were older (75.3 years vs 73.3 years; P = .0005), had had only femoral artery access used (95.8% vs 90.3%; P < .0001), and were more likely to have undergone aortic branch vessel procedures (32.3% vs 13.3%; P < .0001). Both all-cause and aorta-related mortality through 2 years was higher in the reintervention group than in the primary EVAR group (21.4% vs 12.5% [P = .0003; and 4.6% vs 1% [P < .0001], respectively). On multivariate analysis, the predictors of aortic-related mortality included reintervention, renal insufficiency, chronic obstructive pulmonary disease, underweight body mass index, increasing aortic diameter, and the use of brachial artery or other arterial access sites. CONCLUSIONS: Endovascular reintervention for aortic pathology was associated with higher mortality than was primary EVAR. Reinterventions after prior OAPs were associated with higher mortality than were prior EVARs.

Operative management of an incidental portal vein aneurysm in the setting of an incarcerated congenital diaphragmatic hernia.

Portal vein aneurysms are rare pathologic entities. A 3.7-cm portal vein aneurysm was incidentally discovered in an 80-year-old male patient on imaging for acute abdominal pain secondary to an incarcerated diaphragmatic hernia. The aneurysm was resected, and primary repair of the portal vein was performed during a second-look operation after repair of the incarcerated hernia. Operative intervention was chosen for this patient because of the aneurysm's size and the additional indication for abdominal exploration.

Comparative history of Campylobacter contamination on chicken meat and campylobacteriosis cases in the United States: 1994-2018.

In many countries campylobacteriosis ranks as one of the most frequently reported foodborne illnesses and poultry is the commodity that is most often associated with these illnesses. Nevertheless, efforts to reduce the occurrence of pathogen contamination on poultry are often more focused on Salmonella. While some control measures are pathogen specific, such as pre-harvest vaccination for Salmonella, improvements in sanitary dressing and interventions applied during the slaughter process can be effective against all forms of microbial contamination. To investigate the potential effectiveness of these non-specific pathogen reduction strategies in the United States, it is helpful to assess if, and by how much, Campylobacter contamination of chicken meat has changed across time. This study assesses change considering data collected in both slaughter and retail establishments and comparing observed trends in contamination with trends in human surveillance data. The results support the assertion that substantial reductions in Campylobacter contamination of chicken meat in the late 1990s and early 2000s contributed to a reduction in the human case rate of campylobacteriosis. Further reductions in chicken meat contamination between 2013 and 2018 are more difficult to associate with trends in human illnesses, with one contributing factor being the inclusion of culture independent diagnostic test results in the official case counts during that time. Other contributing factors are discussed.

The Western United States has Greater Antibiotic Resistance Among Salmonella Recovered from Intestinal Cecal Samples of Food Animals.

As part of the National Antimicrobial Resistance Monitoring System (NARMS) activities, the United States Department of Agriculture (USDA) Food Safety Inspection Service (FSIS) collected cecal samples from food animal slaughter facilities throughout the country between 2014 and 2018. Of the 26,780 cecal samples from cattle, swine, chicken and turkey , 6,350 (23.71%) tested positive for Salmonella . NARMS tested Salmonella for susceptibility to aminoglycosides, folate pathway inhibitors, macrolides, phenicols, quinolones, beta lactams, and tetracyclines. Using the regional subdivisions defined in the USDA Office of Investigation, we used chi-square test to assess potential association between the region from which the samples were collected and both Salmonella prevalence and susceptibility. The results show a significant association between region and Salmonella prevalence, when accounting for source and establishment size, with the southeast region having the highest probability of finding Salmonella . However, the western region had the highest resistance probability across all antimicrobial classes except for macrolides, which showed no regional association. This association between region and resistance was strongest among isolates from cattle. Analysis of whole-genome sequencing data indicated that a significantly higher prevalence of Salmonella Newport in cattle in the western region (accounting for 9.52% of cattle isolates, compared to 3.44% in other regions) may account for the greater resistance to multiple drug classes. Approximately 90% of Salmonella Newport in the west exhibited the MDR-AmpC phenotype encoded by aph(3'')-Ib/aph(6)-Id , bla CMY-2 , floR , sul2 , and tetA. . Thus, differences in resistance across regions may be due to geographical differences in the prevalence of specific Salmonella serotypes and their accompanying resistance genes.

Factors Associated With Medication Adherence in Vascular Surgery Patients.

INTRODUCTION: Patients with vascular disease have higher mortality rates than age-matched peers and medical management of coexisting diseases may alter these outcomes. We sought to understand factors associated with medication nonadherence in vascular surgery patients at a single University vascular surgery clinic over a 3-month period. MATERIALS AND METHODS: Consecutive vascular surgery patients were surveyed from June to August 2019. The survey included demographic questions, the validated Morisky Medication Adherence Scale, the 4-item Patient Health Questionnaire for Anxiety and Depression scales, and other medication-related questions. Medical and surgical histories were retrospectively collected from charts. Univariate and multivariate analyses were used to compare among high, intermediate, and low adherence. RESULTS: A total of 128 (74%) of 174 patients met study inclusion criteria. On univariate analysis, lower medication adherence was associated with younger age (P = .004), anxiety and depression (P = .001), higher daily pain (P < .001), and patients who believed their medications were less important for treating their vascular disease (P < .001). Adherence was not associated with symptomatic vascular disease, gender, education level, marital status, employment, insurance, or the use of medication usage reminders. Multivariate analysis significantly predicted high adherence relative to low adherence with 5-year increase in age (odds ratio [OR] = 1.252, P = .021) and low adherence relative to high adherence with greater perceived pain (OR = 0.839, P = .016). CONCLUSIONS: Younger age and high level of pain were associated with lower medication adherence. Informing patients of the importance of prescribed medication and addressing anxiety or depression symptoms may improve adherence.

Changes in Salmonella Contamination in Meat and Poultry Since the Introduction of the Pathogen Reduction and Hazard Analysis and Critical Control Point Rule.

ABSTRACT: In 1996, the Food Safety and Inspection Service (FSIS) published its pathogen reduction and hazard analysis and critical control point (PR-HACCP) rule. The intention of this program was to reduce microbial contamination on meat, poultry, and egg products. The program was implemented in stages between January 1998 and January 2000, with sampling for Escherichia coli O157:H7 and/or Salmonella in large production establishments beginning in 1998. As the PR-HACCP program begins its third decade, it is reasonable to question whether there have been reductions in the frequency of pathogen-contaminated meat and poultry products reaching consumers. This study summarizes the results for over 650,000 samples collected by FSIS between 2000 and 2018 in slaughter and processing establishments across the United States and compares these results to the roughly 100,000 retail samples collected by the U.S. Food and Drug Administration between 2002 and 2017. The data demonstrate that there has been an overall reduction in the occurrence of Salmonella on meat and poultry products, but the direction and magnitude of change has not been consistent over time or across commodities. Although the available data do not support the identification of causal factors for the observed changes, a historical review of the timing of various factors and policy decisions generates potential hypotheses for the observed changes.

Adoption of Neutralizing Buffered Peptone Water Coincides with Changes in Apparent Prevalence of Salmonella and Campylobacter of Broiler Rinse Samples.

Buffered peptone water is the rinsate commonly used for chicken rinse sampling. A new formulation of buffered peptone water was developed to address concerns about the transfer of antimicrobials, used during poultry slaughter and processing, into the rinsate. This new formulation contains additives to neutralize the antimicrobials, and this neutralizing buffered peptone water replaced the original formulation for all chicken carcass and chicken part sampling programs run by the Food Safety and Inspection Service beginning in July 2016. Our goal was to determine whether the change in rinsate resulted in significant differences in the observed proportion of positive chicken rinse samples for both Salmonella and Campylobacter. This assessment compared sampling results for the 12-month periods before and after implementation. The proportion of carcass samples that tested positive for Salmonella increased from approximately 0.02 to almost 0.06. Concurrently, the proportion of chicken part samples that tested for Campylobacter decreased from 0.15 to 0.04. There were no significant differences associated with neutralizing buffered peptone water for the other two product-pathogen pairs. Further analysis of the effect of the new rinsate on corporations that operate multiple establishments demonstrated that changes in the percent positive rates differed across the corporations, with some corporations being unaffected, while others saw all of the establishments operated by the corporation move from passing to failing the performance standard and vice versa. The results validated earlier concerns that antimicrobial contamination of rinse samples was causing false-negative Salmonella testing results for chicken carcasses. The results also indicate that additional development work may still be required before the rinsate is sufficiently robust for its use in Campylobacter testing.

Updating a 2-class attributes sampling plan to account for changes in laboratory methods.

Advances in microbiological testing methods have led to faster and less expensive assays. Given these advances, it is logical to employ these assays for use in the sampling plan of an existing microbiological criterion. A change in the performance characteristics of the assay can affect the intended effect of the microbiological criterion. This study describes a method for updating a 2-class attributes sampling plan to account for the different test sensitivity and specificity of a new assay and provides an example based on the replacement of a culture-based assay with a real-time polymerase chain reaction assay.

Estimating correlation of prevalence at two locations in the farm-to-table continuum using qualitative test data.

The presence or absence of contaminants in food samples changes as a commodity moves along the farm-to-table continuum. Interest lies in the degree to which the prevalence (i.e., infected animals or contaminated sample units) at one location in the continuum, as measured by the proportion of test-positive samples, is correlated with the prevalence at a location later in the continuum. If prevalence of a contaminant at one location in the continuum is strongly correlated with the prevalence of the contaminant later in the continuum, then the effect of changes in contamination on overall food safety can be better understood. Pearson's correlation coefficient is one of the simplest metrics of association between two measurements of prevalence but it is biased when data consisting of presence/absence testing results are used to directly estimate the correlation. This study demonstrates the potential magnitude of this bias and explores the utility of three methods for unbiased estimation of the degree of correlation in prevalence. An example, based on testing broiler chicken carcasses for Salmonella at re-hang and post-chill, is used to demonstrate the methods.

Comparing Characteristics of Sporadic and Outbreak-Associated Foodborne Illnesses, United States, 2004-2011.

Outbreak data have been used to estimate the proportion of illnesses attributable to different foods. Applying outbreak-based attribution estimates to nonoutbreak foodborne illnesses requires an assumption of similar exposure pathways for outbreak and sporadic illnesses. This assumption cannot be tested, but other comparisons can assess its veracity. Our study compares demographic, clinical, temporal, and geographic characteristics of outbreak and sporadic illnesses from Campylobacter, Escherichia coli O157, Listeria, and Salmonella bacteria ascertained by the Foodborne Diseases Active Surveillance Network (FoodNet). Differences among FoodNet sites in outbreak and sporadic illnesses might reflect differences in surveillance practices. For Campylobacter, Listeria, and Escherichia coli O157, outbreak and sporadic illnesses are similar for severity, sex, and age. For Salmonella, outbreak and sporadic illnesses are similar for severity and sex. Nevertheless, the percentage of outbreak illnesses in the youngest age category was lower. Therefore, we do not reject the assumption that outbreak and sporadic illnesses are similar.

When Are Qualitative Testing Results Sufficient To Predict a Reduction in Illnesses in a Microbiological Food Safety Risk Assessment?

Process models that include the myriad pathways that pathogen-contaminated food may traverse before consumption and the dose-response function to relate exposure to likelihood of illness may represent a "gold standard" for quantitative microbial risk assessment. Nevertheless, simplifications that rely on measuring the change in contamination occurrence of a raw food at the end of production may provide reasonable approximations of the effects measured by a process model. In this study, we parameterized three process models representing different product-pathogen pairs (i.e., chicken-Salmonella, chicken-Campylobacter, and beef-E. coli O157:H7) to compare with predictions based on qualitative testing of the raw product before consideration of mixing, partitioning, growth, attenuation, or dose-response processes. The results reveal that reductions in prevalence generated from qualitative testing of raw finished product usually underestimate the reduction in likelihood of illness for a population of consumers. Qualitative microbial testing results depend on the test's limit of detection. The negative bias is greater for limits of detection that are closer to the center of the contamination distribution and becomes less as the limit of detection is moved further into the right tail of the distribution. Nevertheless, a positive bias can result when the limit of detection refers to very high contamination levels. Changes in these high levels translate to larger consumed doses for which the slope of the dose-response function is smaller compared with the larger slope associated with smaller doses. Consequently, in these cases, a proportional reduction in prevalence of contamination results in a less than proportional reduction in probability of illness. The magnitudes of the biases are generally less for nonscalar (versus scalar) adjustments to the distribution.