A systematic review has been unable to establish the proportion of food poisoning cases in the United Kingdom caused by food preparation and handling practices within consumers’ homes.

Such estimations would help focus further research, interventions and food safety messages between domestic and other settings. The Chartered Institute of Environmental Health (CIEH) led the work and said to confirm with any certainty the proportions of illness deriving from different settings was difficult.

The  home kitchen is recognized as a point in the field-to-table chain where risks of contracting foodborne disease can be minimized through good hygiene practices but, for many reasons, these practices are frequently not implemented.

It was commissioned by the Food Standards Agency and done by CIEH with the University of Surrey and Cardiff Metropolitan University from January 2016 to March 2018.

Most studies suggest the highest proportion of foodborne illness is from commercial food service settings. Outbreaks in these settings are more likely to be reported because they are investigated and represented in official statistics.

“Results show a complicated picture for attribution of foodborne incidence to the domestic setting, with variable results and many caveats around lack of information, inability to confirm organism, investigation of different agents, differing surveillance systems and levels of reporting by setting, and the use largely of reported cases,” according to the review.

International studies attributing foodborne illness within the home had incidence rates from 12 to 64 percent and commercial foodservice settings in 21 to 85 percent. For studies in the UK, the home was implicated in 12 to 17 percent of outbreaks and food service between 44 to 85 percent of outbreaks (Eves et al., 2017). The European Food Safety Authority reported between 36 and 39 percent of outbreaks are attributed to the home setting in 2011, 2014 and 2015.

Risk factors for contracting foodborne illness include inadequate temperature control in storage (often prolonged) and cooking/reheating, handling raw meat/poultry, eating under cooked meat/poultry/eggs, consumption of barbequed meat/poultry, having unpasteurized dairy products, inappropriate hygiene-related behaviors, contact with animals or nappies and incontinence pads, inadequate hand washing leading to contamination of many sites and inadequate sanitation of boards/knives.

However, only temperature control was linked directly to illness and the number of such cases was very small. Of 278 academic articles evaluated, 71 were included in the review with 21 items from the gray literature, followed by an expert workshop.

Risk factors
Most foodborne disease from errors in food preparation and handling in the home are likely to be sporadic cases. This makes them less likely to be reported and investigated or to appear in surveillance data and official estimates of illness.

Data from the review was not sufficiently reliable to draw conclusions about the proportion of foodborne cases caused by specific pathogens. Norovirus and Clostridium perfringens were more often linked to food service settings.

Research pointed to the potential of refrigerator temperature and fridges harboring pathogens to contribute to the risk of contracting foodborne illness, with a large proportion of domestic appliances operating above 5 degrees Celsius.

Studies also showed that frequently used cleaning practices may not be adequate to remove contamination – including washing of chopping boards – and that organisms may survive and proliferate on some surfaces.

They also illustrated the potential of hands to cross contaminate, and for common cooking regimes to be only marginal in removing pathogens. A number of works also identified contamination of knobs and handles in the kitchen. There was considerable failure to follow good hygienic practice with poor hand washing, use of contaminated surfaces and utensils, cross-contamination and some disregard for date labelling.

The report found further studies with a clear focus on foodborne illness from the home are required to permit a reasonable estimation of the disease burden from this setting.

“To fully understand the extent and causes of food poisoning deriving from the home will require a comprehensive study of foodborne illness, with timely and extensive follow up to enable attribution of illness to the home setting and identification of vehicles and practices that increase the risk of contracting foodborne illness.”

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