SEFARI fellowship: the older population and foodborne illness

The background literature focuses on the growing population of individuals aged ≥65 years globally and in Scotland. It emphasises the increased susceptibility of the population to foodborne illness and the prevalence of illness such as listeriosis, salmonellosis, campylobacteriosis and norovirus. The literature also examines underlying health conditions and medications such as cancer, diabetes, and proton pump inhibitors that further increase susceptibility. 

Additionally, the literature includes consumer food safety research from the past decade, encompassing global, UK, and Scottish studies, and explores behavioural models in order to understand why certain food safety behaviour may exist. Cumulatively, the studies reviewed in the background literature provide a strong rationale for undertaking this body of work, and the need to better understand and reduce foodborne risks among individuals aged ≥65 years in Scotland.

Older adult consumers remain an important group for food safety researchers. Globally, the proportion of people aged 60 years and older in the population is expected to increase from 12% to 22% between 2015 and 2050 (World Health Organization, 2022), and in 2020, for the first time in history, people aged 60 years or over outnumbered children under 5 years (United Nations, 2021). In the UK, the 2021 Census reported that there were over 11 million people in the older age groups, representing 19% of the total population, compared with 16% during the previous census in 2011 (Office for National Statistics, 2022). This now includes over half a million people who are at least 90 years of age (Office for National Statistics, 2022). As reported in Scotland's Census (2023), 20% of the 5,436,600 population are adults aged ≥65 years. 

Senescence, defined as “biological ageing”, is the gradual deterioration of functional characteristics in the human body due to increasing age, the ageing immune system is less efficient in its response, increasing the risk of severe outcomes and invasive disease among older individuals (Chen et al., 2016; Parry et al., 2013; Scallan et al., 2015a, 2015b). 

Ageing affects innate immunity; however, the underlying molecular events are not well understood (Goronzy & Weyand, 2013). Much more is known about adaptive immunity. Ageing results in slower production of T-cell and B-cells by immune system organs, causing the decline in immune system function (Montecino-Rodriguez et al., 2013). As the immune system progresses through senescence, older adults become more vulnerable to foodborne infections. In essence, the greater the age, the higher the risk of foodborne illness.

In high-income countries, the greatest increases in the prevalence of multimorbidity commonly occur in two periods: between the ages of 50 and 60 years, and in advanced old age (≥70 years) (WHO, 2015). Indeed, the risk of severe outcome and incidence of invasive foodborne illness resulting in complications and mortality increase with age (Parry et al., 2013; Scallan et al., 2015a). 

While ageing related changes are unavoidable, their timing varies widely among individuals. Furthermore, the incidences of chronic inflammatory diseases (e.g. cardiovascular disease, diabetes, cancers, etc.) also increase during this time. As described in the Food Standards Scotland report regarding clinically vulnerable groups (Evans & Ilic, 2024), the underlying conditions among older adults, and the medications used to treat or manage such conditions, increase susceptibility among older adults to foodborne illnesses even further. Ageing individuals are also likely to experience multimorbidity. Management of these conditions that occur more frequently in older individuals (adults aged ≥65 years) require chronic medications that reduce levels of stomach acid as a side effect (Dumic et al., 2019), such medications are also documented in the recent Food Standards Scotland report regarding clinically vulnerable groups (Evans & Ilic, 2024) as having a significant impact on the prevalence of foodborne illness. 

Due to complex overall ageing processes involved, immune system senescence occurs at a different pace in individuals. However, in the literature, 60 is frequently cited (WHO, 2015) as the age when the immune system is considered senescent in most ageing adults. The age of 65 is commonly cited in the literature describing foodborne illness infection, however, this cut-off may not be aligned with the physiology of the ageing immune system (Evans & Ilic, 2024). 

To enable an understanding of foodborne illness prevalence among older adults in Scotland, published data from Public Health Scotland and Food Standards Scotland were accessed. Additionally, unpublished reports and datasets were obtained from Public Health Scotland. Prevalence data from Scotland have been discussed alongside global data to gain an understanding of prevalence in Table 1. The incidence, hospitalisation and mortality rates from global studies have also been obtained to understand the susceptibility of adults aged ≥65 years to foodborne illnesses and to explore is if severity of illness varies according to age. 

Listeria surveillance data obtained from Public Health Scotland indicate that 68% of the 166 laboratory confirmed cases of listeriosis between 2012 – 2022 were aged ≥65 years; the 75-79 age band accounted for 18% of the cases. Although data show an increase in prevalence after the age of 65 years, data indicate that 7.2% of listeriosis cases were among people aged 60 – 64 years, compared 3.6% among the 55 – 59 years age band. Of the 10 known deaths believed to be associated with listeria, nine were among those aged ≥65 years (Public Health Scotland, no date).

Numerous global studies also report that the median age of listeriosis cases is ≥65 years (Bennion et al., 2008; Charlier et al., 2017; Gillespie et al., 2009; Gori et al., 2020; Preußel et al., 2015; Suominen et al., 2023; Vallejo et al., 2022). 

Prevalence data in global studies range from 30% of cases among people aged ≥65 years in Portugal (Almeida et al., 2006) to 76% of cases in Germany (Wilking et al., 2021), Australia (OzFoodNet Working, 2012) and England (Gillespie et al., 2010). The incidence rate of listeriosis in Finland was reported to be 11-fold greater in those aged ≥75 years compared to other age groups (Suominen et al., 2023). Similarly, in England, incidence rate for listeriosis peaked in adults ≥60 years, which were 4.4 times the rate compared with children 0-4 years old (Scobie et al., 2019). Furthermore, the mortality rate associated with listeriosis increased with age, those aged 60-69 years, the mortality rate was 30%; among those aged 70-79 years, it was 32%; and those aged 80+, it was 36% (Scobie et al., 2019). 

Although incidence of listeriosis is relatively low in comparison to other foodborne illnesses, severity of illness is high, and data suggest that adults aged ≥65 years are particularly susceptible and are disproportionately affected. 

Of the 3,726 laboratory confirmed cases of non-typhoidal Salmonella in Scotland over the period 2013-2017, 15% were among those aged ≥65 years (Public Health Scotland, Unpublished-d). Although data suggest a peak in young adults, an increase was observed in middle aged adults and a decline in older adults. Mean length of stay increased with age particularly among those aged over 74 years, with the highest proportion of hospitalisations among those aged ≥80 years (Public Health Scotland, Unpublished-d). The cost burden on hospitals from confirmed Salmonella cases increases with age due to the higher rate of hospitalisation and a longer hospital stay among the older adult cases. This increased length of stay may be associated with other conditions (Public Health Scotland, Unpublished-b).

Similar to data obtained from Scotland, global prevalence studies suggested that between 9 – 17% of salmonellosis cases were among older adults (Akil, 2021; Gradel et al., 2008; Graziani et al., 2015; Sala Farre et al., 2015; Tumuhairwe et al., 2008). Incidence rate in Australia increased from 2.4 per 100,000 for those aged 60-69 years to 5.2, and 4.8 per 100,000 for age groups 70-79 years and 80+ (Parisi et al., 2019). 

Although the reviewed studies do not suggest that older adults are disproportionally included in prevalence of Salmonella, the severity of illness was greater among adults aged ≥65 years, with the age group having the highest proportion of Salmonella infections requiring hospitalisation (Wilson et al., 2018). The percentage hospitalised for Salmonella and the percentage who died from Salmonella was higher among adults aged ≥65 years than among children aged <5 years or people aged 5-64 years (Scallan et al., 2015b).

Fourteen percent of the 3,358 laboratory confirmed cases of E. coli between 2012 – 2023 in Scotland were aged ≥65 years (Public Health Scotland, Unpublished-a). Age distribution data of non-O157 STEC in Scotland during 2019 reported that 12% of cases were ≥65 years and 13% of E. coli O157 cases were ≥65 years (Public Health Scotland, 2020). These findings are comparable with global data that suggested between 7 – 17% of E. coli cases are among adults aged ≥60 years (Cleary et al., 2021; Gould et al., 2009; Hadler et al., 2018; Kappeli et al., 2011). 

The incidence rate for E. coli among people aged ≥60 years were available for England and Wales (0.98 cases per 100,000 population) (Adams et al., 2016) and the US (0.22 cases per 100,000 population) (Gould et al., 2013), although these studies reported that crude incidence of E. coli infections decreased with increasing age as incidence was lowest among this age group compared to others. It must be acknowledged that the percentage of people hospitalised for E. coli O157 and the percentage who died was higher among adults aged ≥65 years than among children aged <5 years or people aged 5-64 years (Scallan et al., 2015b). Thus, indicating the increased severity of illness among the age group. 

Between 2013 – 2017, 23% of 30,196 confirmed Campylobacter cases in Scotland were aged ≥65 years. Although those aged 60 – 69 years, 70 – 79 years, and 80+ years accounted for 16%, 11% and 5% of cases respectively, the highest percentage of cases was in the 50 – 59 age group (18%) (Food Standards Scotland, 2020a).

Despite lower incidence, the hospitalisation rate among older adults in Scotland increased with age (60-64 years 12%; 65-69 13%; 70-74 years 19%; 75-79 years 24%, and ≥80 years 33%), furthermore the mean length of stay also increased with age. Thus, demonstrating the increased severity of illness to adults aged ≥65 years.

Data from Scotland also indicated that severity of illness was greater among those of older age. Among the 101 cases admitted to an intensive care or high dependency unit for a Campylobacter related condition, 50% were aged ≥65 years (Food Standards Scotland, 2020b) and the mean age of 67.7 years for cases with a severe outcome was >20 years above the mean age for all Campylobacter cases (46.2 years). This may be attributed to the higher rates of underlying medical conditions among the older population. Over the 5-year period, 12 cases died with Campylobacter enteritis with a mean age of 75.5 years (Food Standards Scotland, 2020a, 2020b).

Similarly, in the US, although among adults aged ≥65 years, the rate of infection decreased with age for Campylobacter, the percentage hospitalised for Campylobacter and the percentage who died from Campylobacter was higher among adults aged ≥65 years than among children aged <5 years or people aged 5-64 years (Scallan et al., 2015b). Data from New Zealand also indicated a peak in hospitalisations from Campylobacter among people aged ≥70 years (Baker et al., 2007) The case fatality rate from Campylobacter in the US was highest in persons aged ≥50 years (0.4%) (Vugia et al., 2009).

Data obtained from Scotland regarding the 15,725 confirmed norovirus cases between 2012 and 2023, reported that 60% of cases were among those aged ≥60 years. 

There was a lack of comparable data globally, with only two of the reviewed studies including prevalence of norovirus among adults aged ≥65 years. These studies suggested that of 37 community acquired cases of norovirus in Italy, 22% were among people aged ≥69 years (Pagani et al., 2018) and that the community incidence rate of norovirus in the US was reported to be 75.8 per 1,000 person-years (Grytdal et al., 2016).

Prevalence of foodborne pathogens among adults aged ≥65 years in Scotland and from global studies

Data suggests that underlying conditions are important in relation to the occurrence of foodborne illnesses such as listeriosis. For example, it was reported that the increased incidence of listeriosis among patients ≥60 years old in England and Wales between 2001 and 2007 occurred in those with underlying conditions such as cancer or other conditions whose treatment included acid-suppressing medication.

Goulet et al. (2012) calculated that the risk of listeriosis was significantly greater among those with underlying conditions, for example, when compared with persons <65 years old with no underlying conditions, those with underlying conditions such as chronic lymphocytic leukaemia had a >1000-fold increased risk of acquiring listeriosis. Those with other conditions such as liver cancer; myeloproliferative disorder; multiple myeloma; acute leukaemia; giant cell arteritis; dialysis; oesophageal, stomach, pancreas, lung, and brain cancer; cirrhosis; organ transplantation; and pregnancy had a 100–1000-fold increased risk of listeriosis (Goulet et al., 2012). It was also reported by Goulet et al. (2012) that clinically vulnerable groups whose underlying conditions were associated with the highest incidence of listeriosis accounted for 43% of cases and 55% of deaths, but only 1% of the total population, whereas groups with low incidence accounted for fewer cases (21%) and fewer deaths (21%), but represented 16% of the whole population. A meta-analysis on mortality risk factors for listeriosis reported that clinical predisposing factors included age ≥ 60 years, and predisposing comorbidities included non-haematological malignancies, alcoholism, chronic kidney disease, cardiovascular disease, and pulmonary disease (Huang et al., 2023). Goulet et al. (2012) suggest that the population considered not at risk of listeriosis are those with no underlying condition and aged <65 years.

Elderly patients in Denmark with Salmonella had higher co-morbidity than their matched reference persons (Gradel et al., 2008). Mean age of those with a severe outcome was >20 years above the mean age for all Campylobacter cases (46.2 years), this may be attributed to the higher rates of underlying medical conditions among the older population. Data from Denmark indicate that older adults with Campylobacter had higher co-morbidity than their matched reference persons (Gradel et al., 2008).

The Food Standards Scotland comprehensive review of clinically vulnerable groups defined the groups at increased risk of foodborne illness, a number of these conditions are particularly prevalent among adults aged ≥65 years such as proton pump inhibitor use, diabetes, and cancer. Some of these in the context of foodborne illness are explored further:

Cancer at a young age is rare, most cases of cancer are diagnosed among people aged ≥50 years, cancer rates are reported to increase with age, rising more steeply from around age 50-60. A third of all UK cancer cases are in people aged 75 and over (Cancer Research UK, 2023). Over time, the cells in the body become damaged. Cancer develops when damage in the same cells builds up. Some of this damage happens by chance during normal cell activity. But cell damage is also caused by things outside the body, such as the chemicals in cigarette smoke, alcohol and too much UV radiation from the sun. As a person ages, there is more time for damage in the cells to build up, making cancer more likely (Cancer Research UK, 2023). 

There were 35,379 new cancers registered in Scotland in 2021, with a reported rate of new cancers of 644 per 100,000 population (Public Health Scotland & National Statistics, 2023). The overall risk of developing cancer in 2021 was 30% higher in the most deprived areas compared with the least deprived areas of Scotland (Cancer Research UK, 2022). Incidence rates for cancer in the UK are highest in people aged 85 to 89, and 36% of all cancer cases in the UK are diagnosed in people aged ≥75 years (Cancer Research UK, 2024). In Scotland during 2021, 77% of cancer diagnoses were in people aged ≥60 years (Public Health Scotland & National Statistics, 2023).

In a person with cancer, disease biology causes immune system dysfunctions which reduces the ability to fight infection. For example T-cell responses are modified due to tumoral antigens, and diseases like Hodgkin’s, T-cell lymphomas, leukaemia, myeloma, and chronic lymphocytic leukaemia cause defects in cell-mediated immunity (Evans & Ilic, 2024). Additionally, cancer treatments, lead to immune system dysfunctions. For example, chemotherapy is a cytotoxic drug that affects T-cells, monocytes/ macrophages, neutrophils, and the GI mucosa. Chemotherapy, targeted cell therapy, and some types of radiation temporarily reduce the number of neutrophils in the blood leading to increased risks of foodborne infections (Evans & Ilic, 2024). In a Food Standards Scotland review of 138 prevalence studies, there were 27 identified studies of listeriosis associated with cancer, which found that 8 – 31% of L. monocytogenes cases were among people with cancer and 5 – 14% of cases were associated with cancer treatment (Evans & Ilic, 2024).

Proton pump inhibitors (PPIs) are a class of medications used to treat pathologies related to stomach acid production including indigestion, heartburn, acid reflux, and to prevent and treat stomach ulcers. While the acidic environment of the stomach serves as a chemical barrier against bacterial infection, proton pump inhibitors prevent acid production, resulting in a decreased pH in the stomach which can lead to bacterial overgrowth, increased risk of bacterial aspiration, and changes in the gut microbiomes (Evans & Ilic, 2024).

Increased risk of infection over time has been demonstrated among people using PPIs (Yibirin et al., 2021). Several infections have been linked to ongoing use of this group of medications, however, long-term susceptibility to infections due to past exposures to PPIs has been reported. Increased prevalence of Clostridium difficile infections has been shown in patients with current and past use of PPIs. PPIs are commonly prescribed to ageing adults (Dumic et al., 2019), with 37% of PPI use in individuals aged 65 years and older (Shanika et al., 2023). With ageing populations, the increasing prevalence of chronic diseases, and polypharmacy (simultaneous use of multiple medicines by a patient for their conditions), PPIs have become one of the most prescribed medicines in developing countries due to their effectiveness versus Histamine (Evans & Ilic, 2024).

In Scotland, a three-fold increase in PPI use has been seen between 2001 and 2017 (Godman et al., 2018). During 2019/20 and 2020/21, omeprazole was the most commonly prescribed item in NHS Scotland, accounting for a total of 4.2 million items annually (Public Health Scotland, 2022). PPIs are reportedly overprescribed (Forgacs & Loganayagam, 2008) and are often taken for longer than needed (Farrell et al., 2022). It has been suggested that 41% of older patients in Scotland are prescribed PPIs, 86% of which were inappropriately overprescribed PPIs (Jarchow-MacDonald & Mangoni, 2013).

Among the 138 studies reviewed in the Food Standards Scotland review of clinically vulnerable groups, twelve studies included data detailing the association between PPI use and prevalence of foodborne illness (Evans & Ilic, 2024). Between 16% of L. monocytogenes infections in Germany (Preußel et al., 2015) and 50% of cases in Finland (Suominen et al., 2023) were prescribed proton pump inhibitors in the 90 days preceding infection. In the Netherlands, 9% of Salmonella cases were associated with PPI use (Doorduyn, Van Den Brandhof, et al., 2006). While in relation to Campylobacter, 8 – 13% of cases were associated with recent PPI use (Bouwknegt et al., 2014; Cribb et al., 2022; Doorduyn, Van Den Brandhof, et al., 2006; Tam et al., 2009).

Diabetes is a chronic inflammatory disease characterised by high blood glucose levels and the inability to produce or efficiently utilise insulin (Alberti & Zimmet, 1998). The mechanisms behind the impairment of the immune system in diabetes are multi-layered and have been only partially elucidated. High glucose and low insulin levels in diabetes lead to changes in the immune system. Dysfunctions of both innate immunity (neutrophils and macrophages) and adaptive immunity (loss of cytokines, impaired antibody production by T-cells) contribute to weak immune response against foodborne pathogens. Additionally, autonomic neuropathy in diabetes affects upper and lower GI tract, causing heartburn, nausea, vomiting, diarrhoea, constipation, and bloating, all leading to disruption of mucosal barrier and immune system dysfunction. Finally, microbiome dysbiosis also contributes to susceptibility to foodborne infections (Evans & Ilic, 2024). Diabetes is cited as a predisposing factor for listeriosis, salmonellosis, and other foodborne infections (Hu et al., 2013; Steinbrecher et al., 2023).

The Scottish Diabetes Survey reported that there were 339,018 people with diabetes in Scotland at the end of 2022. This represents 6.2% of the Scottish population (NHS Scotland & Scottish Diabetes Data Group, 2023). Type 1 diabetes accounted for 10.5% of all cases and type 2 diabetes accounted for 87.8% of all cases of diabetes in Scotland (NHS Scotland & Scottish Diabetes Data Group, 2023). Other forms of diabetes (e.g. gestational diabetes, latent autoimmune diabetes of adults, monogenic diabetes, maturity onset diabetes of the young, neonatal diabetes) are less common (1.7%) (NHS Scotland & Scottish Diabetes Data Group, 2023). It is estimated that a further 49,000 people have undiagnosed type 2 diabetes and that at least 620,000 people in Scotland are at high risk of developing type 2 diabetes (NHS Research Scotland, 2023). By 2035, it is estimated that more than 480,000 people in Scotland will be living with diabetes (Diabetes UK, 2024). It has been reported that prevalence of Type 2 diabetes (6% in 2022) increased with age from 1-5% of adults aged 16-54 to 10-16% of those aged 55 and above (Scottish Government, 2023).

Data detailing the prevalence of diabetes among foodborne illness in Scotland are available for L. monocytogenes and Salmonella. Of the 166 listeriosis cases in Scotland between 2012 – 2022, 10% were among people with diabetes, it was further reported that 94% of which were aged >65 years (Public Health Scotland, no date). European data suggest that 8 – 29% of listeriosis cases are associated with diabetes (Charlier et al., 2017; Doorduyn, de Jager, et al., 2006; Gerner-Smidt et al., 2005; Gillespie et al., 2009; Gori et al., 2020; Koch & Stark, 2006; Preußel et al., 2015; Suominen et al., 2023). 

In relation to Salmonella, Turgeon et al. (2017) reported that 19% of Salmonella hospitalisations among older adults in Canada had both cardiovascular disease and diabetes as underlying conditions and Cummings et al. (2010) reported that 8% of Salmonella-related deaths in US had diabetes, 5% of confirmed Salmonella cases between 2013-2017 in Scotland were reported to have diabetes listed as an underlying condition (Food Standards Scotland, 2020a).

As discussed in sections 3.2, 3.3, and 3.4, individuals over the age of 65 years have increased risk of foodborne illness, consequently, implementation of food safety practices by this group are of critical importance. 

A systematic review by Evans and Redmond (2014) examined consumer food safety knowledge, attitudes, self-reported practices and behaviours. It was established that only 7% of research studies included food safety data for older adults. The reviewed studies suggested that older adults reported some potential food safety malpractices, and concluded that further in-depth research is needed to explore older adults' food safety attitudes, actual behaviours, and self-reported practices to gain a more comprehensive understanding of domestic food safety in this population (Evans & Redmond, 2014).

Given a decade has passed since the systematic review (Evans & Redmond, 2014), a comprehensive review of literature was undertaken to consolidate consumer food safety research undertaken with consumers aged ≥65 years since 2014, in addition to the studies undertaken by the fellow, a further 18 studies were identified. 

Seven studies have been undertaken in the US; Kavanaugh, Fisher, and Quinlan (2021) used focus groups to identify food safety risks among older adults in the US. The study aimed to understand the barriers older adults face in adopting safe food handling practices. The findings revealed that older adults often engage in unsafe food practices due to limited knowledge or cognitive decline. For instance, they reported using outdated methods of food storage, such as keeping perishable items at improper temperatures, or not washing hands before handling food (Kavanaugh et al., 2022).

Yap et al. (2019) found that many older adults in the US fail to follow basic food safety guidelines, such as washing hands before preparing food, storing food at proper temperatures, and thoroughly cooking meat. These unsafe practices increase the risk of foodborne illness. Cognitive decline, physical disabilities, and lack of access to proper food storage facilities were identified as primary contributors to these risky behaviours and suggest that many older adults are unaware of the importance of these practices, and they often lack the ability to implement them consistently (Yap et al., 2020).

Kosa et al. (2019) reported that older adults were significantly less likely to follow safe handling practices, such as using separate chopping boards for raw poultry and other foods, washing their hands after handling raw poultry, and using food thermometers to ensure safe cooking temperatures than the parents of young children in the US (Kosa et al., 2019). 

Jackey et al. (2017) explored food label knowledge, usage, and attitudes among older adults in the US and reported that many older adults struggle to understand food labels, especially information about expiration dates, ingredients, and food safety warnings. This lack of understanding can lead to improper food handling, such as consuming expired foods or misunderstanding storage instructions (Jackey et al., 2017).

Wunderlich et al. (2015) focused on food safety practices at congregate meal sites for older adults in the US. While the meal sites generally adhered to food safety standards, the study found that some older adults were unaware of or did not follow safe food handling practices, such as not consuming meals within recommended time frames or not refrigerating leftovers promptly (Wunderlich et al., 2015).

McWilliams et al. (2017) investigated the food safety practices of homebound seniors in the US who receive home-delivered meals, findings indicate that improper storage, delayed consumption, inadequate refrigeration, and poor reheating practices are prevalent among older adults (McWilliams et al., 2017).

Yu et al., (2018) explored consumer food safety risk receptions in the US and reported that baby boomers (individuals over 60) were significantly less likely than millennials to pay a premium for fresh-cut produce with a lower risk of foodborne illness, suggesting generational differences in risk perception and food safety priorities (Yu et al., 2018).

In Italy, Laurenti et al. (2020) conducted a study to understand the factors that affect the ability of older adults to maintain a safe and healthy diet. The study found that older adults face numerous challenges, including a lack of knowledge about safe food handling practices, limited access to fresh food, and difficulties in meal preparation. Many older adults rely on prepared or processed foods. Social isolation and economic constraints were also identified as significant barriers to maintaining a healthy diet (Laurenti et al., 2020).

In a Canadian study, Thaivalappil et al. (2020) applied the Theory of Planned Behaviour to examine older adults' intentions to adopt safe food storage practices. The study found that older adults' intention to follow safe food storage practices was influenced by their attitudes toward food safety, perceived behavioural control, and subjective norms. Older adults with positive attitudes toward food safety were more likely to implement proper storage practices. However, the study also found that cognitive and physical limitations, as well as lack of knowledge, hindered older adults from adopting safe practices (Thaivalappil et al., 2020).

In another Canadian study, Tooby et al., (2021) explored the consumption of high-risk Foods in the Canadian population which determined that older adults reported consuming high-risk foods of concern, including deli meats and soft cheeses (Tooby et al., 2021).

In Egypt, El Sakhy, Mohamed, and El Sherbini (2020) conducted a study on the food safety knowledge, practices, and attitudes of community-dwelling older adults. The study revealed that older adults had significant gaps in their knowledge about food safety. Many were unaware of proper food storage practices and did not follow guidelines on safe food preparation or cooking. Inadequate food safety knowledge, combined with limited access to resources and physical challenges, led to unsafe food practices (Sakhy et al., 2020).

In South Korea, Lee and Lee (2021) examined the food hygiene awareness, knowledge, and behaviours of older adults which determined gaps existed between knowledge and practice, and that while many older adults were aware of food safety principles, their actual behaviours do not always align with best practices.

In Germany, Berger et al. (2023) investigated older adults’ risk perception, beliefs, and self-perception in relation to kitchen hygiene and food safety. Focus groups indicated that older adults had confidence in their food safety knowledge and skills (Berger et al., 2023).

Although research data detailing older adults' food safety practices exists globally, UK-specific data is essential to account for regional differences. During the past decade the SEFARI Fellow has published six empirical studies regarding the food safety perceptions and practices of older adults in Wales. These studies have shown that while older adults generally acknowledge the importance of food safety, they do not perceive themselves at risk of foodborne illness, and their self-reported practices do not always align with observed behaviours in kitchen settings. The studies have identified risky food handling, inadequate storage practices in domestic refrigerators, and potential microbiological contamination in home kitchens (Evans & Redmond, 2015, 2016a, 2016b, 2018a, 2019a, 2019c). In addition to these six studies, four other food safety studies were undertaken in the UK that focused on older adult consumers.

Wills et al. (2015) explored the behaviours and practices of older people that might contribute to foodborne illnesses. The study found that older adults often did not recognise the risk of foodborne diseases because of their longstanding habits and assumptions about food safety. Even though many older adults believed they had never experienced foodborne illness, the study showed that their food safety practices, such as inadequate handwashing, improper storage of food, and undercooking, contributed to a higher risk of foodborne infections (Wills et al., 2015).

Dickinson et al. (2014) conducted the first Kitchen Life study to explore food safety and hygiene practices among older adults in the UK. The study found that older people often face barriers to safe food handling, particularly due to cognitive and physical impairments, such as memory loss, arthritis, and visual impairments. These factors made it difficult for older adults to maintain proper food safety practices, such as storing food at correct temperatures, checking food expiry dates, and following hygiene guidelines. The study also identified that social isolation and living alone were significant contributors to unsafe food practices, as older adults were less likely to seek advice or help with food safety (Dickinson et al., 2014). 

Bloom et al. (2017) investigated factors influencing diet quality in older adults in the UK and also addressed food safety indirectly by exploring the food choices. The research revealed that older adults often made food choices that prioritised convenience over food safety, such as consuming ready-to-eat or pre-prepared meals that may not always follow the recommended food safety guidelines. Additionally, cognitive decline and health problems led some older adults to rely on unbalanced diets, which could contribute to poorer food safety outcomes.

Meah et al. (2017) examined the food safety behaviours of older consumers in the UK. The research determined that there was a significant gap in knowledge about food safety among older adults, particularly concerning food storage, handling raw meat, and recognising foodborne illness symptoms. The study also revealed that many older adults were not aware of the risks posed by improper food handling, and this lack of awareness increased their vulnerability to foodborne illnesses.

Like the global studies identified, the ten UK-based studies on older adults' food safety practices also highlighted cognitive and physical barriers, risky food handling behaviours, and reliance on convenience foods. None of the UK studies specifically refer to including participants from Scotland, most refer to a general UK populations or specific regions such as England. Although some of the studies may have included participants from different regions within the UK without explicitly isolating data from Scotland. 

Although Food Standards Agency undertook research with people over the age of 60 years old in Scotland to explore views and behaviour in relation to their food hygiene at home. The research found that older adults in Scotland were confident in their food hygiene practices, the study concluded that more information on not washing raw poultry and adhering to use by dates was needed for the target audience (Food Standards Agency, 2014). This study was undertaken in 2014, no further research has been undertaken with older adults in Scotland. 

There is a need for more Scotland-specific research on older adults’ food safety practices to address regional variations in diet, accessibility, socioeconomic challenges, and public health policies, ensuring that food safety education interventions are relevant to the Scottish population.

Having reviewed global, UK, and Scotland based food safety studies, it can be concluded that many of these studies capture data detailing the knowledge, attitudes, self-reported practices and observed behaviours of older adult consumers relating to food safety in the domestic setting. These studies indicate potential food safety challenges faced by older adults and suggest how cognitive decline, physical limitations, lack of knowledge, and social factors such as isolation and economic constraints may contribute to risky food handling and storage practices. Cumulatively, these studies indicate food safety malpractices among older adults, as they may not perceiving themselves as being susceptible to foodborne illnesses, however further exploration is required to understand why such perceptions and practices exist. To enable this there is a need apply an appropriate behavioural model.

Using behavioural models to understand why certain food safety behaviours exist among older adults is essential, this is particularly important to enable the development of effective, targeted interventions to improve food safety practices among the target audience in the future.

The Health Belief Model (Rosenstock, 1974) suggests that specific health behaviours are influenced by an individual's perceptions of severity and personal susceptibility, combined with perceived benefits and barriers to that behaviour. For an individual to adopt a specific behaviour, the perceived threat and benefits must outweigh the perceived barriers. Personal factors, such as self-efficacy and cues to action are also frequently included in the model (Etheridge et al., 2023). One of the publications from my PhD (Evans & Redmond, 2019d) established that older adults expressed perceptions of invulnerability, optimistic bias, and the illusion of control regarding food safety; they perceived themselves to have lower levels of risk than other individuals, and perceived themselves to have greater levels of control and responsibility than others. We believe that such perceptions may undermine attempts to provide education regarding food safety (Evans & Redmond, 2019d).

Although some studies have utilised the Health Belief Model in the food safety context (Cho et al., 2013; Hanson & Benedict, 2002; Hanson et al., 2015; McArthur et al., 2006; Schafer et al., 1993; Wang et al., 2021), a recent study by Kavanaugh et al (Kavanaugh et al., 2022) utilised the Health Belief Model to explore food safety risks among older adults in the US, which determined that utilising the definitions of perceived barriers and cues to action appear applicable to older adults’ food handling behaviours and suggested that the Health Belief Model could be utilised as a framework to develop future interventions for older adults. Nevertheless, they suggested that when the Health Belief Model is used with older adults for food safety research, there is a need to modify the perceived threat construct to not only include the perceived susceptibility and perceived severity, but the perceived risk that a food may be contaminated and cause illness (Kavanaugh et al., 2022). 

Consequently, there is a need to understand the modifying factors that can influence people’s perceptions and practices relating to food safety. Some previous non-food safety studies, have demonstrated that modifying components of the Health Belief Model, including age, financial security, health literacy, and spirituality can impact upon health behaviours such as attending medical appointments (Cronin et al., 2018). Other models have been used to explore food safety among the group of interest. For example, safe food storage practices among older adults in Canada were explored using the theory of planned behaviour to determine which psychosocial factors predicts intentions to adopt safe food practices at home (Thaivalappil et al., 2019).

However, the research fellow believes that obtaining an understanding of the impact of these modifying factors is something that we can improve in food safety research, for this it was proposed that the Dimensions of Wellness could be utilised to give structure to identify the modifying factors that may influence food safety malpractices among older adults. People often think about wellness in terms of physical health, such as nutrition, exercise, and weight management, however “Wellness” is a holistic integration of eight mutually interdependent dimensions: physical, intellectual, emotional, social, spiritual, vocational, financial, and environmental (Stoewen, 2017). These dimensions could be used to describe some basic human needs, and have been used in research with older adults to explore how some of these dimensions may protect cognition in ageing (Strout & Howard, 2012). Although these dimensions are intended to focus on an individual’s wellbeing. The research fellow believes that these dimensions can be utilised to give us a defined structure to the modifying factors within the Health Belief Model to enable us to explore why certain food safety practices or malpractices are part of people’s lives.