Cognitive, Behavioral and Microbial Analysis of Older Adult Consumers' Domestic Risk Factors Associated with Listeriosis

Introduction: In Europe, Listeriosis associated with older adult consumers has reportedly increased three-fold (1990s-present), with majority of international incidence and mortality associated with older adults. Listeriosis is predominantly sporadic and associated with refrigerated extended shelf life Ready-to-Eat (RTE) foods; therefore, consumer implementation of temperature control, ‘use-by’ date adherence and ensuring maximum two days storage after opening is essential to ensure food safety. Older adults are reported to be frequent consumers of RTE foods; however, data on older adults’ domestic storage practices of RTE foods are lacking. 

Purpose: Qualitative and quantitative research methods were used to determine older adults’ domestic storage practices of RTE foods to evaluate the potential impact on L. monocytogenes and Listeriosis risk. 

Methods: One hundred older adults (≥ 60years) participated in the mixed-methods study involving a ‘model kitchen’ food preparation session; self-complete questionnaire, computer-assisted personal-interview, home-kitchen microbiological survey and domestic refrigerator time-temperature profiling. Study findings informed development of laboratory re-enactment using RTE foods spiked with L. monocytogenes to determine potential impact of storage malpractices on food safety.

Results: Although knowledgeable of some recommended practices, older adults’ self-reported and actual behavioral data indicate such practices are not always implemented. Many older adults failed to express positive attitudes towards such practices; additionally, the majority of refrigerators operated at temperatures exceeding recommendations (≤ 5.0°C). Identified common malpractices, particularly prolonged storage of RTE foods and inadequate refrigeration temperatures were widespread; re-enactment of which determined L. monocytogenes growth was significantly greater (P < 0.001) than following recommendations, thus potentially making RTE foods unsafe for consumption and increasing the risk of listeriosis. 

Significance: This study utilized novel data collection methods and increases our understanding of older adults’ domestic RTE food storage practices which have been microbiologically determined to increase the potential risk of Listeriosis. Findings may inform the development of targeted consumer food safety education.