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Home truths: encouraging good domestic hygiene

Debbie  Stevens
BSc(Hons) MSc
Research Scientist
Associate Member International Scientific Forum on Home Hygiene

Effective cleaning and good basic hygiene can go a long way in helping to prevent the spread of infections, we are told. Yet sometimes even healthcare professionals fail to adhere to this advice - let alone consumers.(1)
Cases of hospital-acquired infections have increased in recent years. For example, government figures reveal that cases of methicillin-resistant Staphylococcus aureus (MRSA) in England and Wales rose from just over 1,600 in 1996 to almost 5,700 in 2003,(2) but this may be a conservative estimate. MRSA Support, a support group for sufferers of MRSA, also claims that the likely annual death toll from MRSA is more than 30,000.
At the end of 2004 the government published a list of England's dirtiest hospitals, revealing that most hospitals had borderline levels of cleanliness. "Filthy wards" and "sloppy hygiene procedures" are often blamed by the media as the cause, yet simple handwashing can have a significant positive impact on preventing the spread of hospital-acquired infections.
Health Secretary John Reid has called for rates of MRSA infection to be halved by March 2008,(3) and to help tackle the problem he appointed Christine Beasley as Chief Nursing Officer for England during 2004, whose priority is to improve hospital cleanliness and tackle MRSA and other hospital-acquired infections.

Home to thriving infection
However, just as microbes such as MRSA can thrive in hospitals, so too can many others within the home. Patients leaving hospital need to take extra care when returning home, as they may be particularly vulnerable to infection. Healthcare professionals need to look beyond their workplaces for the spread of infection and not neglect the importance of educating patients about the significance of home hygiene.
There are an estimated 9.4 million cases of infectious intestinal disease (IID) in England and Wales each year,(4) and the Food Standards Agency (FSA) believes that up to half of IID cases are due to food poisoning.(5) In 2003 there were a reported 70,895 cases of food poisoning, according to the Health Protection Agency (HPA).(6) The Consumers' Association has suggested that these figures are merely the tip of the iceberg, as so many cases go unreported, and the real figures could be as much as 30 times higher.
In most cases, food poisoning symptoms clear up within days, but for vulnerable groups - including children under 5, pregnant women, the elderly, people who are immunocompromised and those taking immunosuppressive drugs - the consequences can be more serious, and even fatal. The FSA aims to reduce the incidence of food poisoning by 20% by 2006.(5)
A number of efforts have been made to raise awareness of the importance of hygiene in the catering industry. An FSA survey among catering managers and staff about food hygiene knowledge and behaviour in the workplace showed that a shocking 39% of those questioned don't wash their hands after visiting the toilet at work, and thus a campaign has begun to improve hygiene in the industry.(7)
But are people really taking these messages on board in their own homes? It is estimated that up to 40% of foodborne outbreaks in Europe arise from within the home.(8) European data suggest that more than 50% of Salmonella and Campylobacter infections are home-based.(9) The home is a potentially dangerous area for the spread of infection, yet it is much easier to prevent bugs thriving in the home than it is in hospitals. This is provided people know about day-to-day hygiene measures, understand their importance and create an environment in which the whole family stick to the "hygiene rules".
Practice nurses are in a particularly good position to help educate consumers about potential infections in the home, and how to avoid them. The subject can be discussed during routine procedures, following a specific case of food poisoning or when a patient is pregnant.
Vulnerable groups, including pregnant women, need to be particularly conscientious and keep their homes hygienically clean with a disinfectant such as bleach (the only household disinfectant that kills all types of bacteria and inactivates viruses), which will help to minimise the risk of infection.

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What lurks beneath
Campylobacter, the most common of the foodborne pathogens associated with food poisoning, has a sudden onset, with symptoms including nausea, vomiting and diarrhoea. Pets may carry Campylobacter, and it can also be contracted through eating undercooked meats or transferring bacteria from uncooked food to cooked or prepared food. Up to 83% of chickens are contaminated with Campylobacter.(10) Only a few Campylobacter need to be present in food or drink to cause illness.
Salmonella, the second most common cause of food poisoning, has been found in raw egg products, raw meat and poultry, and raw unwashed vegetables. It can grow in food - quickly multiplying unless the food is adequately chilled - and it can survive if food is not cooked thoroughly. It is estimated that 25% of chickens brought into UK homes contain Salmonella.(10)
While most strains of Escherichia coli are harmless, the verocytotoxin-producing E coli 0157 can cause serious illness, including kidney failure and even death. The household transmission rate for sporadic E coli 0157 infection in the UK is estimated at 4-15%.(11) E coli 0157 has been transmitted through raw and undercooked meats, dairy products (especially inadequately pasteurised milk), raw vegetables and unpasteurised apple juice. Thorough cooking and pasteurisation are needed to kill the bacteria.
Similarly, cooking and pasteurisation are required to kill Listeria monocytogenes, as this bacterium can still grow at low temperatures, such as in the fridge. Found in raw meat, poultry, cheeses (particularly soft mould-ripened cheeses and pâtés), it can be fatal in the elderly and debilitated.
Clostridium perfringens produces heat-resistant spores, which can survive the cooking process. Problems tend to occur if food is not reheated to a high-enough temperature (at least 60˚C), as the bacteria will multiply rapidly from the spores. This bacteria is mainly associated with foods that are left standing warm for long periods of time, such as stews, gravies and cooked meat dishes.

Hygiene holes
All aspects of home hygiene are based on the same underlying microbiological principles, which means people can tackle the risks logically. Achieving sterility is unnecessary and anyway a near-impossible task, but microorganisms can be reduced to a level that is not harmful to health.
Of foodborne IID cases in the home, 39% are due to inappropriate storage of food.(12) Home-cooked and purchased cold foods such as ham contain only small numbers of pathogens - insufficient to cause disease. But if left in warm, moist conditions, organisms such as Salmonella can multiply within hours, causing the food to become highly contaminated.
A further 20% of IID cases are caused by poor hygiene standards by food handlers.(12) In the kitchen, microorganisms can be transferred from one food to another - for instance, by a person's hands, a chopping board or drips from raw food onto cooked food. Cloths and sponges can spread contamination as bacteria can survive on the wet surfaces of these materials. The cleaning materials should be soaked regularly in a diluted bleach solution, and then rinsed and dried thoroughly.
Of the remaining IID cases, 31% are caused by inadequate cooking and reheating.(12) After heating, food must spend a minimum amount of time between 30 and 45oC. If not eaten immediately, food should be cooled to prevent growth of bacteria and then stored in the fridge until ready to be reheated.

Pinpointing the hot spots
There are four major considerations when looking at the most practical ways to improve home hygiene:

  • The sources whereby intestinal pathogens enter the home (eg, people, contaminated food, pets).
  • Identification of the routes of transfer of these pathogens to potential victims. These routes can include hands, cleaning cloths and chopping boards, as well as unexpected places such as light switches and door handles - all of these areas should be regularly decontaminated with a bleach-based product. 
  • Assessment of the risk posed by the transfer of these agents (particularly important if a family member is pregnant, very young or very old).
  • Identification of safe and effective hygiene procedures for eliminating - or reducing - the number of microorganisms.

Conclusion
Once good hygiene habits are developed, they will become second nature and have a significant impact on the spread of microorganisms in the home. People will become used to washing their hands after high-risk activities such as using the toilet, handling raw food or gardening, and always cleaning surfaces with a disinfectant such as bleach before and after preparing raw food, as they come to realise how important it is. But many people do not practise these measures yet - simply because they are unaware of their importance - and despite their best efforts they may be not be cleaning successfully (eg, using a contaminated dishcloth to clean surfaces). Increasing awareness of good hygiene practices can go a long way in helping to combat the spread of microorganisms.

References

  1. Stein AD, Makarawo TP, Ahmad MFR. A survey of doctors' and nurses' knowledge, attitudes and compliance with infection control guidelines in Birmingham teaching hospitals. J Hosp Infect 2003;54:68-73.
  2. Health Protection Agency. Staphylococcus aureus bacteraemia laboratory reports and methicillin susceptibility (voluntary reporting scheme): England and Wales, 1990-2003. Available from URL: http://www.hpa.org.uk/infections/topics_az/staphylo/lab_data_staphyl.htm
  3. Health Protection Agency. Bloodborne MRSA infection rates to be halved by 2008 - Reid. Press release;5 Nov 2004. Available from URL: http://www.dh.gov.uk/PublicationsAndStatistics/PressReleases/PressReleases Notices/fs/en?CONTENT_ID=4093533&chk=MY%2BkD/
  4. Wheeler JG, Sethi D, Cowden JM, et al. Study of infectious intestinal disease in England: rates in the community, presenting to general practice and reported to national surveillance.BMJ 1999;318:1946-50.
  5. Food Standards Agency. Agency launches food hygiene campaign. Press release - 11 Feb 2002. Available from URL:http://www.food.gov.uk/news/pressreleases/2002/feb/campaignlaunch
  6. Health Protection Agency. Food poisoning notifications - annual totals England and Wales, 1982-2003. Available from URL: http://www.hpa.org.uk/infections/topics_az/noids/food_poisoning.htm
  7. Food Standards Agency. Food Hygiene Campaign: your questions answered. Available from URL: http://www.food.gov.uk/multimedia/faq/fhc2qanda/?version=1
  8. World Health Organization. Several foodborne diseases are increasing in Europe. Press release; 16 Dec 2003. Available from URL: http://www.euro.who.int/eprise/main/who/mediacentre/PR/2003/20031212_2
  9. Scott E. Developing a rational approach to hygiene in the domestic setting. J Infect 2001;43:45-9.
  10. Jorgensen F, Bailey R, Williams S, et al. Prevalence and numbers of Salmonella and Campylobacter spp. on raw, whole chickens in relation to sampling methods. Int J Food Microbiol 2002;76:151-64.
  11. Parry SM, Salmon RL, Willshaw GA, Chesty T. Risk factors for and prevention of sporadic infections with verocytotoxin (shiga toxin) producing Escherichia coli O157.Lancet 1998;351:1019-22.
  12. Gillespie IA, O'Brien SJ, Adak GK. General outbreaks of infectious intestinal diseases linked with private residences in England and Wales, 1992: questionnaire study. BMJ 2001;323:1097-8.