Research report

‚ÄčThe fate of surrogate verocytotoxic E. coli contaminating the rhizospheres of root vegetables during processing and retail and wholesale distribution

1 documents for this subject


This project was funded by Food Standards Scotland and Food Standards Agency to provide better understanding of the survivability of E. coli at all stages along the vegetable production and distribution chain.

In recent years there have been a number of high-profile foodborne disease illness outbreaks that have been associated with fresh produce. In particular, in 2011 epidemiological data linked an outbreak of E. coli O157 in Great Britain to the handling and preparation of vegetables that had contaminated soil on the surface. Therefore FSS and FSA wanted to investigate the extent to which E. coli could survive on the surface of soil contaminated vegetables and the potential risk to consumer health.

There are many types of E. coli and not all of them are harmful to humans. However the strains that produce a toxin called verotoxin are pathogenic and are called verocytotoxic E. coli (VTEC), of which E. coli O157 is one type. This study used a naturally occurring non-pathogenic E. coli O145 that has previously been implicated in foodborne illness associated with eating fresh produce. It was used to contaminate vegetables (potatoes, carrots and leeks) a week before harvest. The project looked at pre and post-harvest consequences of contaminated manure and irrigation water accidentally being applied to the crops and assessed the impact of contamination as the vegetables progressed through the production chain. For example, the spread of pathogens to wash water from produce that had been contaminated.

The outcomes of the study showed that after a worst case scenario situation (i.e. escaped cattle getting into the field or irrigation water becoming contaminated) occurring, E. coli O145 could be isolated from both potatoes and leeks after harvest. However when replicating commercial processes of brushing, washing and storage they eliminated or significantly reduced the contamination on the vegetables. E. coli O145 was more likely to be recovered from vegetables stored at a constant refrigerated temperature (retail) compared with crops stored at ambient temperatures (wholesale), possibly due to the bacteria becoming stressed and dying during temperature fluctuations.

The study also assessed the effect of handling vegetables by gloved or ungloved harvest workers with poor hygienic practices. The results confirmed the importance of workers adopting a good handwashing technique following a visit to the bathroom and that when gloves were worn there was lower contamination passed to the vegetables. The study also recommended that surfaces such as flush handles and door latches are cleaned regularly.

The results from this project will be used by Food Standards Scotland to inform future risk assessments and food safety advice in relation to fresh produce.

Arrow_Dropdown Created with Sketch. Arrow_leftArrow_Right Icon_AlchoholIcon_Alchohol_RoundalIcon_AppleIcon_Apple_RoundalIcon_BacteriaIcon_Bacteria_Roundal calorie-outlined Created with Sketch. Icon_CardActivityIcon_CardActivity_RoundalIcon_CarrotIcon_Carrot_Roundal Icon/roundal/Allergen/Celery Created with Sketch. Icon_CertificateIcon_Certificate_RoundalIcon_CheeseIcon_Cheese_RoundalIcon_ChocolateIcon_Chocolate_RoundalIcon_ClipboardIcon_Clipboard_Roundal Icon_CloseIcon_CowIcon_Cow_Roundal Shape Created with Sketch. Icon/roundal/Allergen/Crustaceans Created with Sketch. Icon_CursorIcon_Cursor_RoundalIcon_DeerIcon_Deer_RoundalIcon_download Icon/roundal/Allergen/Eggs Created with Sketch. Icon_Facebook_RoundalIcon-FeaturedIcon_Fish Icon/roundal/Allergen/Fish Created with Sketch. Icon_Fish_RoundalIcon_FizzyJuiceIcon_FizzyJuice_RoundalIcon_ForkIcon_Fork_RoundalIcon_FridgeIcon_Fridge_Roundal Icon/roundal/Allergen/Wheat Created with Sketch. Icon_GrainIcon_GrainNoIcon_GrainNo_RoundalIcon_Grain_RoundalIcon_GraphIcon_GraphResourceIcon_Graph_RoundalIcon_HandIcon_Hand_RoundalIcon_HeartIcon_Heart_RoundalIcon_InfoIcon_Info_Roundal instagram Icon_LambIcon_Lamb_RoundalIcon_LetterIcon_Letter_RoundalIcon_LinkExternalIcon_LinkInternal Icon/roundal/Allergen/Lupin Created with Sketch. Icon_MagnifyingGlassIcon_MagnifyingGlass_Roundal Icon/roundal/Allergen/Milk Created with Sketch. Icon/roundal/Allergen/Molluscs Created with Sketch. Icon/roundal/Allergen/Mustrard Created with Sketch. Icon_NewIcon_NewsIcon_News_RoundalIcon_OilIcon_Oil_Roundal Icon/roundal/Allergen/Peanuts Created with Sketch. Icon_PeopleIcon_People_RoundalIcon_PersonIcon_Person_RoundalIcon_PhoneIcon_Phone_RoundalIcon_PigIcon_Pig_RoundalIcon_PlayIcon_PotatoesIcon_Potatoes_RoundalIcon_PrintIcon_Print_RoundalIcon_ResourceIcon_Resource_Roundal Group Created with Sketch. Icon_SaltIcon_Salt_RoundalIcon_SaveIcon_Save_RoundalIcon_ScotlandIcon_Scotland_RoundalIcon_Search Icon/roundal/Allergen/Sesame Seeds Created with Sketch. Icon_ShellfishIcon_Shellfish_Roundal Icon/roundal/Allergen/Soybeans Created with Sketch. Icon-SpiralIcon_SteakIcon_Steak_RoundalIcon_StopwatchIcon_Stopwatch_Roundal Icon/roundal/Allergen/Sulphur dioxide and sulphites Created with Sketch. Icon_TapWaterIcon_TapWater_RoundalIcon_TestTubeIcon_TestTube_RoundalIcon_ThumbsUpIcon_ThumbsUp_RoundalIcon_Tick Shape Created with Sketch. Icon_Tick_1Icon_Tick_Roundal Icon_TomatoIcon_Tomato_RoundalIcon_TractorIcon_Tractor_Roundal Icon/roundal/Allergen/Tree nuts Created with Sketch. Icon_TrollyIcon_Trolly_RoundalIcon_TurkeyIcon_TurkeyCookedIcon_TurkeyCooked_RoundalIcon_Turkey_Roundal Icon_Twitter_RoundalIcon_WarningIcon_Warning_Roundal Icon_Warning_Roundal_WithBG Icon_WaterDropIcon_WaterDrop_RoundalIcon_WineBottleIcon_WineBottle_RoundalIcon_WineGlassIcon_WineGlass_Roundal youtube Icon_snowflakeIcon_snowflake_RoundalLogo_FSS_Gaelic_WhiteLogo_FSS_WhitePagination_LeftArtboard 69