THE BUG THAT SHOOK EUROPE-ARE OTHERS SAFE?

In the wake of the deadly deadly Escherichia coli ( E.Coli) outbreak that's swept Europe in recent days, a logical question that worries food safety experts is whether such episodes can happen elsewhere in the world. The issue is too complex to get a ready answer since E.coli, considered for long as an innocuous bug has metamorphosed into a monster group of microorganisms capable of causing death amongst humans. It was known for quite some time that a virulent strain of E.coli can cause food poisoning and it was identified as E.coli 0157:H7 which can damage the kidney if infected, though early treatment can abate the symptoms. Almost a decade of tireless work by microbiologists resulted in evolving reliable techniques to identify and assay them, giving considerable confidence to safety monitoring agencies to nip such poisoning with reasonable degree of accuracy. In some countries mandatory testing of foods for 0157:H7 is in place to prevent large scale food poisoning. In spite of all these efforts, more than 60000 people per year are affected by food poisoning episodes in the US alone due to infection from this bacteria.

There are also several other virulent strains isolated from soil but very little is known about most of these dangerous versions and practically no reliable assay method has been evolved that can be applied in the field. Thus there are gaps in the food safety systems of most of the countries as it is not feasible to test for new illnesses emerging caused by various strains of pathogenic E.coli. It is true that most safety agencies are focusing on a single strain, 0157:H7 considered most dangerous, ignoring other strains which also caused occasional food poisoning episodes to a limited extent. Now that the culprit in the EU food contamination case has been tentatively identified as E.coli 0104:H4, world has to sit and take note of the potential for damage by this strain. Probably the EU incidence may be a wake-up call for agencies like WHO to channel more resources to tackle this menace.

Why should this bacteria infect such products like tomato, cucumber, aubergine or lettuce which after all are not energy dense products giving sustenance to them? Could it be that they are just carriers becoming active only when suitable environment is available? How do they survive the rigorous processing steps which include washing and disinfection practiced by the industry most of them following the HACCP practices? Do they possess extra-ordinary capacity to with stand the scientifically sound disinfection processes followed by the industry? How come they possess the ability to resist antibiotics used for treatment of affected consumers? What precaution consumers can take to avoid ingesting such deadly foods? These are all disturbing questions that need to be probed without any delay.

Some of the clues available are helpful in understanding the problem and these must be kept in mind while evolving preventive action to avoid such contamination taking place at the grower's end and at industry level. E.coli is a bacteria associated with feces and they live in the guts of most mammals including human beings. Unless the affected product was exposed to an environment containing these bacteria in adequate numbers, it is unlikely that they would be contaminated. It would be advisable for fresh produce industry to ensure that at least a distance of 5 ft is kept between areas containing E.coli sources and the produce materials. The reported fact that those affected by the food poisoning are not responding to antibiotics Penicillin and Streptomycin points out to the possibility of raw meat as a source of contamination because the meat industry uses antibiotics in heavy doses in the feed tending to cause resistance of many pathogens to these antibiotics.

Now that the large outbreak in EU has been more or less traced to the emerging super-strain O104:H4 which is reported to have sickened at least 1,600 people and killed 18, intensive efforts are on to trace the source of contamination so that such future incidences can be avoided. The sacrifices by those unfortunate people felled by this pathogenic bacteria should not go in vain and the mankind owes to them for preventing such tragedy in future.

V.H.POTTY
http://vhpotty.blogspot.com/
http://foodtechupdates.blogspot.com

E.COLI FOOD CONTAMINATION-ASSUMING ALARMING PROPORTION?

The ubiquitous Escherichia coli (E.coli) had never posed any danger to humans until new strains were discovered a few years ago with potential to be dangerous to consumers. Interestingly this bug was routinely being tested as a marker for testing foods for possible contamination with fecal matters during production and handling. The group of E.coli coming under the Enterohaemorrhagic (EHEC) category can cause serious food poisoning, if the food is not properly processed to kill them and it is known to cause even death if not immediately treated. One of the most virulent strains under EHEC is the notorious 0157:P7 which was found to be a major culprit in almost all food poisoning cases in the West.

E. coli belongs to bacterial species and it has been found commonly in the gut of humans and warm-blooded animals. Historically most strains of E. coli are harmless. Enterohaemorrhagic E. coli is an exception in that it can cause severe food borne disease. It is transmitted to humans primarily through consumption of contaminated foods, such as raw or undercooked ground meat products and raw milk. Its significance as a public health problem was recognized in 1982, following an outbreak in the United States of America. EHEC produces toxins, known as verotoxins or Shiga-like toxins because of their similarity to the toxins produced by Shigella dysenteriae. EHEC has the amazing capacity to grow in a wide range of temperatures from from 7°C to 50°C, with the optimum temperature being 37°C. Some EHEC can grow in even in acidic foods, with pH as low as 4.4 and in foods with a minimum water activity (Aw) of 0.95. It can be destroyed completely by adequate cooking of foods to ensure that all parts reach a temperature of 70°C or higher. E. coli O157:H7 is the most important EHEC serotype in relation to public health, though other serotypes are also emerging causing occasional outbreaks.

Symptoms of the diseases caused by EHEC may include abdominal cramps, diarrhea, fever and vomitting. It may take any where from three to eight days for the bacteria to be fully incubated and act in human body though most cases can be diagnosed within three to four days. When properly treated the affected person can recover within 7-10 days, though in a few cases, especially when young children and old people are affected the infection can be life-threatening. Haemolytic uraemic syndrome (HUS) one of the diseases caused by this bug is characterized by acute renal failure, haemolytic anaemia and thrombocytopenia. It is believed that up to 10% of patients with EHEC infection may develop HUS, with a fatality rate ranging from 3% to 5%. It can cause neurological complications including seizure, stroke and coma in about 25% of HUS patients and chronic renal sequelae in around 50% of survivors. Some of the outbreaks due to EHEC have involved a high number of cases, such as in Japan in 1996, where an outbreak linked to contaminated radish sprouts in school lunches affected thousands of children. Data on the situation in most developing countries are limited, as surveillance for this pathogen is not done routinely and documentation practices are not in vogue.

Why is that EHEC infection is reported more commonly in Western countries and other affluent populations where hygiene and sanitation awareness is very high? Why is that this infection does not affect people in countries like India where food crops are cultivated in rural areas where open defecation is practiced with high probability of the crop getting contaminate? Probably because Indians consume almost all their foods in overcooked conditions while the salad eating practice based on raw vegetables is prevalent in the West.The serotype O157:H7 which has been studied extensively, is easily differentiated biochemically from other E. coli strains. Interestingly this bug is present in great numbers in cattle and other ruminants such as camels and is transmitted to humans primarily through consumption of contaminated foods, such as raw or undercooked ground meat products and raw milk.

Fecal contamination of water and other foods, as well as cross-contamination during food preparation containing beef and other meat products, contaminated surfaces and kitchen utensils, will also lead to infection. Examples of foods implicated in outbreaks of E. coli O157:H7 include undercooked hamburgers, dried cured salami, unpasteurized fresh-pressed apple cider, yogurt, cheese and milk. What is worrying the food safety experts is that increasing number of outbreaks are now being associated with the consumption of fresh horticultural produce like sprouts, lettuce, coleslaw, tomato, cucumbers, salad etc, which are eaten raw without thermal processing. Possibly these fresh produce materials are contaminated due to contact with feces from domestic or wild animals at some stage during cultivation, handling and storage.

EHEC has also been isolated from bodies of water (ponds, streams), wells and water troughs, and has been found to survive for months in manure and water-trough sediments. Waterborne transmission has been reported, both from contaminated drinking-water and from recreational waters. Organic foods which are produced using natural manure can be most vulnerable to infection by EHEC. Person-to-person contact is an important mode of transmission through the oral-fecal route. There are also instances where infected individuals show no clinical signs of disease but pass on the infection to others. The duration of excretion of EHEC from the body is about one week or less in adults, but can be longer in children. Visiting farms and other venues where the general public might come into direct contact with farm animals has also been identified as an important risk factor for EHEC infection.

The most recent episode of EHEC food poisoning comes from Austria where many consumers were infected by consuming organically grown vegetables from Spain and that country's food safety agency has cautioned the consumers about the dangers of consuming these tainted fresh produce, advising them further to destroy such dangerous bacteria containing products. Some of the vegetables under the scanner include cucumbers, tomatoes and aubergines. There are reported to be 10 casualties in Germany due to this episode and other member countries of EU are gearing up to tackle this contingency without causing major damage to their citizens. The classical belief that only animal products are contaminated by EHEC needs to be reexamined in the context of such episodes involving fruits and vegetables. Probably predominantly meat consuming countries are vulnerable because of improper management of production farms due to shortage of personnel and over mechanization of many operations. Though meat products are segregated during storage, distribution and retailing there can be cross contamination from these foods affecting fresh produce like fruits and vegetables.

V.H.POTTY
http://vhpotty.blogspot.com/
http://foodtechupdates.blogspot.com

E.COLI- FROM MARKER TO MONSTER!

Escherichia coli is normally a benign gram negative bacterium, found in the lower intestines of warm blooded creatures including humans and often considered beneficial because of its ability to synthesize Vitamin K2 and keeping out pathogens from the body. The famous pediatrician and microbiologist Theodor Escherich of Germany, after whom the bacterium has taken its name, might never have thought, when he discovered it in 1885, that this ubiquitous organism would play a vital role in human health one day. A new born child gets E.coli within 40 hours of its birth through water, food and the persons handling it. There are 700 stereotypes of E.coli identified so far and a few of them can be virulent in causing serious food poisoning. For food scientists E.coli is a critical marker for assessing the microbiological safety of foods and its presence in water or foods is taken as indication of contamination with fecal matter and consequent possibility of presence of pathogenic organisms. Unhygienic food preparations, farm contamination due to manuring, irrigation of crops with contaminated water or raw sewage, all can result in food contamination with unpredictable adverse consequences. Raw ground beef which finds many use in processed foods, raw seed sprouts, spinach, raw milk, unpasteurized juice and foods handled by unhygienic workers under insanitary conditions will invariably be contaminated with E.coli and such foods can pose risks to consumers.

Virulent strains of E.coli include O157:H7 and O121:H19 capable of excreting Shigatoxins, similar to toxins from Shigella; there are also others like O111:B4, O104:H21 etc which are not as dangerous as them. A pin head can hold about 2.5 lakh cells of these microbes, as they are hardly 0.5-2 microns in size and just about 10-50 cells can be fatal to a child or old age person if not treated properly. An estimated 1 lakh cases of human infection with E.coli O157:H7 are reported annually in the Americas with 2-7% developing serious haemolytic uremic syndrome (HUS) causing damage to kidney, intestine, liver and pancreas, eventually leading to coma. 5% of HUS patients, mainly children and old folks die because of higher sensitivity to the toxins. 44 million pounds of beef were recalled in 25 episodes of contamination in the year 2007 alone in USA. The economic burden in treating the affected population is estimated at $ 400 million per year. Why no cases have been reported from India is a mystery though the traditional cooking habits and shunning of cold foods like salads could be the main reasons. Or could it be that such cases are not diagnosed properly and therefore go unreported?.

Cows are known to carry E.coli 0157:H7 but they do not get sick due to their presence in their guts. Contamination usually takes place through contact with cow dung. The cells get attached to the mucus walls of the GI tract and they are regularly shed along with the excreta. The severe damage potential of this pathogen attracted attention of the scientific community and a vaccine has since been developed in Canada being marketed under the brand name Econiche for use amongst the cattle reared in open as well as in restrained environment. The vaccine has already been approved for unrestricted use in Canada and USA for immunizing beef and dairy cattle which significantly reduces shedding of E.coli O157:H7 cells into the environment and consequent lesser risk to human health. Effectively the vaccine prevents the cells of the microbe from attaching to the intestine of the cattle, thereby reducing their reproduction within the animal.

Can E.coli O157:H7 be a serious health hazard ever in India? A difficult question considering that millions of domesticated cows live happily with the human beings at close proximity and cow is an integral part of the rural economy. Either Indian cows do not harbor this virulent type in their body or Indians must have developed high degree of immunity to them over years of close contact and personalized rearing system. Or the habit of Indian population to eat mostly well cooked hot foods and drink boiled milk might be preventing wide scale occurrence of E.coli infection. Or the E.coli strains present in Indian cattle are highly resistant to mutation into virulent forms under Indian conditions and feeding regimen. Nonetheless it is prudent to put in place a national monitoring system, probably under the aegis of National Dairy Research Institute/Indian Veterinary Institute under the ICAR so that the country is well prepared to manage such an epidemic if and when it occurs.

V.H.POTTY
http://vhpotty.blogspot.com/