<p>Retail environments are critical transmission points for <i>Listeria
monocytogenes</i> to humans. Past
studies have shown <i>L. monocytogenes</i> contamination varies widely across
retail environments. <i>L. monocytogenes</i> can transmit among environmental
surfaces and subsequently from environment to food via cross-contamination. Modified
SSOPs (sanitation standard operating procedures) have been shown to have limited
impact on reducing <i>L. monocytogenes</i> prevalence in retail deli
environments. Food safety culture and climate, such as beliefs, values, and
hygiene behaviors, have been identified as factors impacting food safety
performance and microbial outputs. Handwashing and its compliance are among the
most prominent personal hygiene aspects subjected to investigation in the past
decade, illustrating hygiene behavior as a risk factor and an important
consideration to ensure food safety. Additionally, effective management and
well-designed infrastructure, such as vertical and lateral communication,
employees’ training, accountability, and equipment designed to prevent
cross-contamination, have also been described as critical contributors to a sustainable
food safety program. However, given such a deadly foodborne pathogen as <i>L.
monocytogenes</i>, the correlation between food safety culture and its prevalence
remains unknown. We hypothesized that
there was a relationship among food safety culture management, infrastructure,
and <i>L. monocytogenes</i> prevalence at retail. Our goal is to identify additional risk
factors on <i>L. monocytogenes </i>control, develop feasible recommendations, and
direct resources to enhance food safety. </p>
<p>In the present dissertation, we developed and implemented a
predictive risk model, along with employee- and management-implemented SSOPs,
in 50 deli establishments across six U.S. states to evaluate and control <i>L.
monocytogenes</i> contamination risk and prevalence (Chapter 2). The predictive
risk model, based on logistic regression, uses five environmental sites to
predict <i>L. monocytogenes</i> prevalence in the entire deli environment. It identified
13 high-risk stores, seven of which were confirmed during subsequent monthly
sampling. We found that deep clean intervention reduced <i>L. monocytogenes </i>prevalence
on non-food contact surfaces both immediately after the intervention and during
follow-up, with marginal significance (α<sub>adj</sub>=0.0125). The employee-
and management-implemented deep clean can control <i>L. monocytogenes</i>
prevalence in retail delis; the predictive risk model, though conservative,
will require further validations and can be useful for surveillance purposes. </p>
<p>Complementary to the above study, we tackled the <i>L.
monocytogenes</i> challenge via food safety culture and climate approach
(Chapter 3). Concurrently to the monthly environmental sampling, we distributed
food safety culture and climate survey to the 50 stores, with one manager and
up to five associates from each establishment, over a 12-month period and
overlapped with before, after, and follow-up deep clean. We found that stores
with lower <i>L. monocytogenes</i> contamination risk had better food safety
culture, including greater sense of commitment to food safety program (p<sub>adj</sub>=0.0317)
and more complete training (p<sub>adj</sub>=0.0117). Deep clean improved
managers’ (p<sub>adj</sub>=0.0243) and associates’ (p<sub>adj</sub>=0.0057)
commitment to food safety. This study indicates that food safety culture and
climate are crucial component in building a viable, sustainable food safety
program. </p>
<p>Another survey tool was used to evaluate infrastructure
designs, management strategies, and sanitation practices in relation to <i>L.
monocytogenes</i> control in retail produce environments (Chapter 4). We
distributed the survey to 30 retail produce departments across seven U.S.
states. Hand hygiene, minimizing cross-contamination, and maximizing equipment
cleanability were the most prominent factors in <i>L. monocytogenes</i>
control.</p>
| Identifer | oai:union.ndltd.org:purdue.edu/oai:figshare.com:article/12072051 |
| Date | 28 April 2020 |
| Creators | Tongyu Wu (8662944) |
| Source Sets | Purdue University |
| Detected Language | English |
| Type | Text, Thesis |
| Rights | CC BY 4.0 |
| Relation | https://figshare.com/articles/Assessing_Listeria_monocytogenes_contamination_risk_using_predictive_risk_models_and_food_safety_culture_management_in_retail_environments/12072051 |
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