Cross Contamination Example Essay

Cross-Contamination and its Role in Food Poisoning Outbreaks
Cross-contamination is one of the most major causes of food poisoning (Food Standards Agency, 2014). It is defined as ‘the process by which a substance that is harmful or dirty spreads from one area to another’ (Cambridge Online Dictionary, 2014) .There are 3 different types of contamination in the food industry; microbial contamination, physical contamination and chemical contamination, with microbial contamination being a more frequent cause of food poisoning and rising, with the amount of products contaminated having risen 91% between 2006 and 2011 (Department for Environment, Food and Rural Affairs , 2012) . A variety of things can cause microbial cross-contamination, but the most common causes are through vehicles or vectors carrying harmful bacteria (pathogens) from a source to the food. The source or reservoir is where the contamination originates from, for example, humans, raw food, rodents, dust and soil. In the context of cross-contamination, a vehicle is a substance, object or living thing that moves the contaminant away from its source to the food. The vehicle could either be stationary or a mobile vehicle. A vector is an organism, usually a bird or an insect, that transmits a pathogen from one place to another.
The aim for a food manufacturer is to make a commercially sterile, not completely sterile. The definition for a commercially sterile product is “Commercial sterility of food means the conditions achieved by application of heat which renders such food free from microorganisms capable of growing in the food at temperatures at which the food is likely to be held during distribution and storage.” (Food and Agriculture Organisation, 2007). The reason for this is that the severe thermal treatment needed to make a product completely sterile would severely reduce the sensory quality and nutritional value of the product, as well as increasing the energy consumption to reach higher heats.
There are various reasons as to why cross-contamination happens and is a major cause of food poisoning, for example, poor hand washing techniques, confusion of terminology by staff, equipment design and colour coded equipment which people do not adhere to. It is also very difficult to track down the causes of an outbreak, so it may take a while to take the relevant measures to stop the outbreak and sometimes the wrong thing is blamed, for example, in 2011, Spanish fruit and vegetables were blamed for an E. coli outbreak across Europe, killing 22 people. However, it was later discovered that German bean sprouts were the likely cause (BBC News, 2011). The mistake cost the Spanish fruit and vegetable industry £200m per week, proving how economically important it is to get the causes right (BBC News, 2011). In many food poisoning cases, a sequence of events contributes to an outbreak, rather than just one activity alone. This is called the microbial chain and makes it even harder to discover the true cause of an outbreak. An example of a microbial chain is; cooked ham comes into a store and is sliced. This ham has come from the supplier contaminated so has now contaminated the slicer used. The slicer is not washed and other meats, for example, more cooked ham or cooked beef, is sliced on it. This then causes the other meats to become contaminated, making it difficult to find the meat that originally caused the problem. The cooked meat that has been contaminated is ready to eat, so therefore is a high risk product as no further treatment will be done to kill pathogens, meaning it is very likely that a case of food poisoning would come from this microbial chain if the pathogen was harmful enough.

A wide range of things can act as vehicles for microbes, for example, hands, clothes, cleaning cloths and pests can all act as mobile vehicles, and food-contact surfaces, food itself and hand-contact surfaces, such as door handles, fridge door and taps, can all act as stationary vehicles. These vehicles can carry pathogens onto high risk foods such as ready to eat products such as, cooked meats, cooked prawns, oysters, and dairy products. A high risk food can be defined as “any ready-to-eat food that will support the growth of pathogenic bacteria easily and does not require any further heat treatment or cooking”. (Warwick University , 2011). This means that special care needs to be taken preparing these foods in the factory or in the kitchen, for example, using separate areas in the factory or using separate chopping boards for raw and cooked meat in the kitchen.
There are many laws that have been put in place to try and prevent cross-contamination, therefore reducing the frequency of major food poisoning outbreaks. These laws can be found in (EC) 852/2004 Hygiene of Food Stuffs and it is the job of environmental health officers to enforce these laws, through audits. This laws have been changed and updated over time since 2004 to make them more relevant and applicable. A public enquiry on the 2005 E. coli O157 outbreak in South Wales, chaired by Hugh Pennington, a professor of bacteriology, helped further improve this piece of legislation when it was published in 2009. However, many find these difficult to interpret and use in the context of their own business, so the Food Standards Agency created ‘Safe Food Better Business’, with different sections for different types of companies that handle food, for example, for caterers, takeaways, retailers, child minders and care homes. These documents are also provided in different languages to help provide businesses, run by foreign owners who don’t speak English, improve the safety of the food from the business and help them adhere to the laws in (EC) 852/2004, therefore reducing the risk of an outbreak occurring through cross-contamination from this business.
There are many examples of where cross-contamination has been the probable cause of major food poisoning outbreaks, for example, an outbreak of Heston Blumenthal’s ‘The Fat Duck’ restaurant in 2009, the E. coli O157 outbreak in in 2005 in South Wales and an E. coli outbreak in Lanarkshire, Scotland in 1996.
The 2005 outbreak of E. coli O157 in South Wales was a major outbreak and lots of mistakes were made for it to occur, which were highlighted in the Pennington Report. In the outbreak, 157 cases were identified, 31 people admitted to hospital and 1 five year old boy died. This prompted a public enquiry carried out by a Professor in Bacteriology called Hugh Pennington. The problems identified were; poor audits carried out by Environmental Health Officers at John Tudor and Son, critical control points not met, no valid ‘Hazard Analysis and Critical Control Point’ (HACCP) plan and issues with cooked meat being prepared and packed in the same area as raw meat, therefore causing cross-contamination (Pennington, 2009). The meat also ending up in schools in the area, meaning smaller children with weaker immune systems were more at risk of becoming infected, so they were more vulnerable to serious illness and death.
One cause of the outbreak was that there was only one vac packer, which are used to vacuum pack a product, was used for cooked and raw meat, causing any pathogens that were on the raw meat to contaminate the vac packer, which then contaminated the cooked meat. This then became the problem as the cooked meat will not be treated again, so there is a good chance that a harmful level of pathogens will be present in the meat when consumed. Environmental health officers that had inspected the premises had noticed that there was only one vac packer for both, however the Food Business operator had told that they had another vac packer that was of site for repairs. This turned out to be a lie and could have easily been detected, had the inspector enquired further and asked for proof, however it was only discovered to be not true at later inspection. In the Pennington Report it states that ‘special attention’ was paid to the vac packer and that ‘the use of one for both raw and cooked meats carried with it a serious risk of cross-contamination’. This is because it would be extremely difficult to effectively and comprehensively clean the vat packer to the extent that it would be safe. This is partly due to E. coli O157 having a very low infectious dose level, with less than 10 organisms (STATEMENT FROM WIKI, NEED TO FIND PROPER REFERENCE) needed to infect a person, so all E. coli O157 organisms would need to be killed on cooked meat before consumption.
The HACCP plan for the abattoir were not up to the standards they should have been and the environmental health officers failed to take into account the importance of a good HACCP. They therefore failed to identify the weaknesses of the plans, which was a major cause of the outbreak. (Morillo SG, 2011)

In Heston Blumenthal’s Michelin star restaurant ‘The Fat Duck’ in Berkshire, there was an outbreak of norovirus in 2009, with the probable cause being cross-contamination. Norovirus can be transmitted directly from person to person and indirectly through contaminated water and food. It is extremely contagious and fewer than 20 virus particles can cause infection (Morillo SG, 2011). An investigation found that the likely origin of the norovirus came from oysters and other molluscan shellfish contaminated by human sewage in Colchester and Torquay. This then infected the staff and contaminated surfaces, which were then routinely cleaned with cleaning agents known to be ineffective against viruses, causing further contamination of other food. As shellfish were served raw, the norovirus did not undergo heat treatment to destroy the organisms, so the food was not safe to consume.
In total, 529 people reported illness after dining at the restaurant, generally the incubation period was between 24-48 hours after dining at the restaurant. Six stool samples from staff tested positive for norovirus, two of which shared the same accommodation, three tasted the food they were preparing and one prepared seafood. Despite six stool samples being positive for norovirus, and the fact that in (EC) 853/2004, Chapter 8, 2. it states that illness of staff must be reported immediately, only three staff members were recorded by the restaurant as being absent with norovirus symptoms during January and February.
The outbreak lasted for six weeks, which, along with the amount of people infected could have been reduced had procedures and laws been followed. The restaurant did not notify any environmental health officers until the night before a party of diners notified the Thames Valley Health Protection Unit in late-February, after the restaurant had voluntarily closed to undergo a ‘deep cleaning’ process, while the restaurant had become aware of a problem in mid-January. The restaurant had however contacted a private environmental health company to help assist with their investigation in mid-February. This extended the time that it took for environmental health officers to complete their investigation and discover the cause of the outbreak.
During the investigation from the environmental health officers, it was found that some workers had returned to work before the recommended 48 hour exclusion after symptoms like diarrhoea and vomiting have ceased. This is because despite the symptoms having stopped, the person may still have the virus, so will therefore risk infecting other members of staff and contaminating food. The risk of this was further increased by the fact that some staff took no leave, even though they experienced symptoms. This was one of the major reasons why the outbreak effected so many diners at the restaurant.
Once the investigation had been completed, the restaurant reopened subject to certain conditions which had to be met to try and prevent any future outbreaks from happening. One of the conditions was to put in place a restaurant policy for an exclusion period of 72 hours for staff with symptoms of a gastrointestinal illness and explaining to them why this is in place. This will help staff understand why they should stay off and stop cross-contamination, causing further illness. The restaurant was fully decontaminated, using appropriate cleaning products. Basic training for key staff in HACCP were completed and more extensive HACCP courses were to be attended by the executive chef and other head chefs who are in charge of food safety management. This will further help staff understand the actions they need to take to ensure the safety of the food being served and help them understand why it is important to do so. The restaurant reopened on the 29th March 2009, just over a month after it had voluntarily closed.
There are various European Union laws that are designed to improve food safety in 852/2004. For example, in Chapter 1, General Provisions, Article 1, 1. (b) it states that ‘it is necessary to ensure food safety throughout the food chain, starting with the primary production.’ This guarantees that all companies involved in food production know they are an important part in securing food safety, from farmers to retailers such as Tesco or Sainsbury’s. This is important as famers especially can feel they are not an important part of ensuring food safety, which has caused major problems, which may have led to food poisoning outbreaks in the past, for example, the E. coli outbreak in Germany 2011, caused by bean sprouts. Other parts of the law help to reinforce this, for example laws about the HACCP principles help to ensure that every food producer has corrective actions, pre-requisites and critical control points that are effective enough to destroy pathogens and stop a food poisoning outbreak. In the same article, 1. (a), it also states that ‘the primary responsibility for food safety rests with the food business operator’, placing the onus onto him/her to do everything possible to stop a food poisoning outbreak. For example, he would need to provide HACCP training to key staff members, basic food safety to other food handles within the business and make sure the food premises is suitable for food preparation. They could either do this themselves or could employ specialist companies to establish a good premises layout and correct procedures when setting up a company.
There are many laws about the layout and design of a food premises, which can be found in Annex 2, Chapter 1, general requirements for food premises. It includes the location, design and numbers of lavatories, washbasins, ventilation and drainage facilities. It also states that food premises are to be kept and maintained in good repair and condition. These laws ensure that the food premises is hygienic and promotes cleanliness, for example, if there are an adequate number of hand wash basins then there will always be one available to use, rather than staff having to wait, who then might not bother because they have other things to do. This would then increase the risk of cross-contamination occurring and cause a food poisoning outbreak.
Water supply plays an important role in food safety. If the water supply becomes contaminated then all food products that come into contact with that water, are at a much higher risk of becoming contaminated. Cross-contamination would also occur when staff wash their hands, leading to more problems as their hands then become contaminated, which will contaminate anything else that they touch, for example, food products, surfaces or machines. For this reason there are laws in (EC) 852/2004 to ensure that water supplies used in the food chain are ‘adequate’. Annex II, General Hygiene Requirements, Chapter VII: Water Supply outlines the regulations for a water supply. For example, it states that ‘recycled water should not present a risk of contamination and has to be of the same standard as potable water’. Recycled water can sometimes increase the risk of cross-contamination, for example if it had already been used to wash vegetables that may have already been contaminated. It is therefore important to regulate the use of recycled water to make sure the use of it poses no risk to consumers.
Training is an important part of food preparation. Food handlers should be supervised, instructed and/or trained in food hygiene matters that relate to their work activity. This ensures that all they are comfortable with the food they are handling, which reduces the risk of a food poisoning outbreak as the food handlers understand what they need to do to make the food safe. Staff also need adequate training in the application of HACCP principles, meaning they have a basic understanding of safety procedures around their food premises. The training needs to comply with national law concerning training programmes for persons working in certain food sectors. This means there will be an adequate level of knowledge of workers in the food industry. These laws can are found in Annex II, General Hygiene Requirements for all Food Business Operators, Chapter XII, Training.
One of the main techniques used to destroy pathogens in food stuffs is heat treatment. Therefore, under Annex II, General Requirements for all Food Business Operators, Chapter XI, Heat Treatment, there are laws concerning the heat treatment of food stuffs. In this section of law, it states that any heat treatment used should ‘raise every party of the product treated to a given temperature for a given period of time’ and ‘to prevent the product from becoming contaminated during the process.’ This ensure that the food product is cooked properly, reducing the number of pathogens to a reasonable level, so the food is commercially sterile, and that no contamination occurs due to the process of heat treatment. This helps to maintain a high level of food safety within the industry.

References
BBC News, 2011. Deaths from E. coli still rising in Germany. [Online]
Available at: http://www.bbc.co.uk/news/world-europe-13746682
[Accessed 03 04 2014].
BBC News, 2011. E. coli outbreak: First German sprout tests negative. [Online]
Available at: http://www.bbc.co.uk/news/world-europe-13672161
[Accessed 03 04 2014].
Cambridge Online Dictionary, 2014. Cambridge Dictionaries. [Online]
Available at: http://dictionary.cambridge.org/dictionary/british/cross-contamination?q=cross+contamination
[Accessed 02 04 2014].
Department for Environment, Food and Rural Affairs , 2012. Food Statistics Pocketbook 2012. [Online]
Available at: http://webarchive.nationalarchives.gov.uk/20130103014432/http:/www.defra.gov.uk/statistics/files/defra-stats-foodfarm-food-pocketbook-2012-121005.pdf
[Accessed 02 04 2014].
Food and Agriculture Organisation, 2007. Canning/Sterilization of Meat Products. [Online]
Available at: http://www.fao.org/docrep/010/ai407e/ai407e22.htm
[Accessed 03 04 2014].
Food Standards Agency, 2014. Cross-contamination. [Online]
Available at: 2014 http://www.food.gov.uk/northern-ireland/nutritionni/niyoungpeople/survivorform/dontgetsick/crosscontamination#.UzxFf_ldXpt
[Accessed 18 04 2014].
Morillo SG, T. M., 2011. Norovirus: an overview, s.l.: s.n.
Pennington, H., 2009. The Public Inquiry into the September 2005 Outbreak of the E. coli O157 in South Wales, s.l.: s.n.
Pennington, H., n.d. s.l.: s.n.
Warwick University , 2011. High and Low Risk Foods. [Online]
Available at: http://www2.warwick.ac.uk/services/healthsafetywellbeing/guidance/foodhygieneandsafety/highandlowriskfoods/
[Accessed 03 04 2014].

References: BBC News, 2011. Deaths from E. coli still rising in Germany. [Online] Available at: http://www.bbc.co.uk/news/world-europe-13746682 BBC News, 2011. E. coli outbreak: First German sprout tests negative. [Online] Available at: http://www.bbc.co.uk/news/world-europe-13672161 Cambridge Online Dictionary, 2014. Cambridge Dictionaries. [Online] Available at: http://dictionary.cambridge.org/dictionary/british/cross-contamination?q=cross+contamination Food and Agriculture Organisation, 2007. Canning/Sterilization of Meat Products. [Online] Available at: http://www.fao.org/docrep/010/ai407e/ai407e22.htm Food Standards Agency, 2014. Cross-contamination. [Online] Available at: 2014 http://www.food.gov.uk/northern-ireland/nutritionni/niyoungpeople/survivorform/dontgetsick/crosscontamination#.UzxFf_ldXpt Morillo SG, T. M., 2011. Norovirus: an overview, s.l.: s.n. Pennington, H., 2009. The Public Inquiry into the September 2005 Outbreak of the E. coli O157 in South Wales, s.l.: s.n. Warwick University , 2011. High and Low Risk Foods. [Online] Available at: http://www2.warwick.ac.uk/services/healthsafetywellbeing/guidance/foodhygieneandsafety/highandlowriskfoods/