Probabilistic risk model of norovirus transmission during handling and preparation of fresh produce in school foodservice operations

Impact of Training on Employees' Handwashing Behaviors in School Nutrition Programs

BACKGROUND

School nutrition employee behavior plays an important role in preventing foodborne outbreaks and protecting the almost 30 million children who partake in daily school lunch.

OBJECTIVE

The study aim was to compare the impact of using a food safety training program with or without using a realistic-event video on handwashing behavior modification for school nutrition employees.

DESIGN

A 2-group (control and experimental) pretest with 2 post-tests design was used. The control group received training without the video and the experimental group received the food safety training with a realistic-event video. Measurements used to address the purpose and objectives of this study included questionnaires and direct observations.

PARTICIPANTS/SETTING

The sample consisted of 443 school nutrition employees responsible for food preparation and service affiliated with 21 school districts in 18 states. Approximately half of the sample attended the original unmodified training and the other half attended the modified training. Data were collected in the United States during 2017. A total of 338 employees participated in the observations and 443 participants completed the questionnaires during the 3 phases; 935 questionnaires were used for the analysis.

INTERVENTION

The intervention involved a food safety training program embedded with a realistic-event video related to handwashing. The video used previous research to target antecedents to handwashing behavior among participants.

MAIN OUTCOME MEASURES

Actual behavior was observed across 3 phases-pretraining, post training, and final-for both the control and experimental groups. In addition, indirect and direct measures of behavioral intentions for handwashing were measured.

STATISTICAL ANALYSIS PERFORMED

For the observation data, a 2-way, fixed-effects, mixed-model procedure was used to analyze the data. Simple and multiple linear regression and contingency table analyses looking for differences among phases and treatments were used for questionnaire data analysis.

RESULTS

Most practices were reported as in compliance (51.3% to 80.6%) for both the control and experimental groups during all phases. The experimental group had a higher behavioral intention of properly washing their hands than participants in the control group.

CONCLUSIONS

The results showed that handwashing practices were in compliance most of the time for both the control and experimental groups during all 3 observation periods. Differences among the data collection periods on the theory of planned behavior constructs indicated no statistical effect of the treatment (exposure to the video) between the control and intervention groups.

Norovirus transmission mitigation strategies during simulated produce harvest and packing

In the agricultural setting, core global food safety elements, such as hand hygiene and worker furlough, should reduce the risk of norovirus contamination on fresh produce. However, the effect of these practices has not been characterized. Using a quantitative microbial risk model, we evaluated the individual and combined effect of farm-based hand hygiene and worker furlough practices on the maximum risk of norovirus infection from three produce commodities (open leaf lettuce, vine tomatoes, and raspberries). Specifically, we tested two scenarios where a harvester's and packer's norovirus infection status was: 1) assumed positive; or 2) assigned based on community norovirus prevalence estimates. In the first scenario with a norovirus-positive harvester and packer, none of the individual interventions modeled reduced produce contamination to below the norovirus infectious dose. However, combined interventions, particularly high handwashing compliance (100%) and efficacy (6 log10 virus removal achieved using soap and water for 30 s), reduced produce contamination to <1-82 residual virus. Translating produce contamination to maximum consumer infection risk, 100% handwashing with a 5 log10 virus removal was necessary to achieve an infection risk below the threshold of 0.032 infections per consumption event. When community-based norovirus prevalence estimates were applied to the harvester and packer, the single interventions of 100% handwashing with 3 log10 virus removal (average 0.02 infection risk per consumption event) or furlough of the packer (average 0.03 infection risk per consumption event) reduced maximum infection risk to below the 0.032 threshold for all commodities. Bundled interventions (worker furlough, 100% glove compliance, and 100% handwashing with 1-log10 virus reduction) resulted in a maximum risk of 0.02 per consumption event across all commodities. These results advance the evidence-base for global produce safety standards as effective norovirus contamination and risk mitigation strategies.

Predicting population level hip fracture risk: a novel hierarchical model incorporating probabilistic approaches and factor of risk principles

Fall-related hip fractures are a major public health issue. While individual-level risk assessment tools exist, population-level predictive models could catalyze innovation in large-scale interventions. This study presents a hierarchical probabilistic model that predicts population-level hip fracture risk based on Factor of Risk (FOR) principles. Model validation demonstrated that FOR output aligned with a published dataset categorized by sex and hip fracture status. The model predicted normalized FOR for 100000 individuals simulating the Canadian older-adult population. Predicted hip fracture risk was higher for females (by an average of 38%), and increased with age (by15% per decade). Potential applications are discussed.