food poisoning overview

8/7/2019 Food Poisoning Overview

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Food Poisoning Overview

Food poisoning is a common, usually mild, but sometimes deadly illness. Typical symptomsinclude nausea, vomiting, abdominal cramping, and diarrhea that occur suddenly (within 48hours) after consuming a contaminated food or drink. Depending on the contaminant, feverand chills, bloody stools, dehydration, and nervous system damage may follow. These

symptoms may affect one person or a group of people who ate the same thing (called anoutbreak).

y The Centers for Disease Control and Prevention (CDC) estimates that in the UnitedStates, food poisoning causes about 76 million illnesses, 325,000 hospitalizations, andup to 5,000 deaths each year. One of the most common bacterial forms of infection,

the salmonellae organisms, account for $1 billion in medical costs and lost work time.

y Worldwide, diarrheal illnesses are among the leading causes of death. Travelers todeveloping countries often encounter food poisoning in the form oftraveler's diarrheaor "Montezumas revenge." Additionally, there are possible new global threats to theworld's food supply through terrorist actions using food toxins as weapons.

Food Poisoning Causes

More than 250 known diseases can be transmitted through food. The CDC estimatesunknown or undiscovered agents cause 81% of all food-borne illnesses and relatedhospitalizations. Many cases of food poisoning are not reported because people suffer mildsymptoms and recover quickly. Also, doctors do not test for a cause in every suspected casebecause it does not change the treatment or the outcome.

y The known causes of food poisoning can be divided into two categories: infectiousagents and toxic agents.

o Infectious agents include viruses, bacteria, and parasites.

o Toxic agents include poisonous mushrooms, improperly prepared exotic foods(such as barracuda), or pesticides on fruits and vegetables.

y Food usually becomes contaminated from poor sanitation or preparation. Foodhandlers who do not wash their hands after using the bathroom or have infectionsthemselves often cause contamination. Improperly packaged food stored at the wrongtemperature also promotes contamination.


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What Is Food Poisoning?

Food poisoning comes from eating foods that contain germs likebad bacteria or toxins, which are poisonous substances. Bacteria are all around us, so mildcases of food poisoning are common. You may have had mild food poisoning withdiarrhea and an upset stomach but your mom or dad just called it a stomach bug orstomach virus.

You might think the solution is to get rid of all the bacteria. But it isn't possible and youwouldn't want to do it, even if you could. Bacteria are all around us, including in food, andsometimes they can be good for you. It's confusing, but one thing is for sure the bacteria inthe rotten leftovers weren't good for you. But you can learn how to avoid those bad germs infood.


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y Campylobacter jejuniwhich can lead to secondaryGuillainBarr syndromeandperiodontitis[4]

y Clostridium perfringens, the "cafeteria germ"[5]y Salmonella spp. its S. typhimurium infection is caused by consumption of eggs that are not

adequately cooked or by other interactive human-animal pathogens[6][7][8]

Salmonella

y Escherichia coli O157:H7enterohemorrhagic (EHEC) which causeshemolytic-uremicsyndrome

Othercommon bacterial foodborne pathogens are:

y Bacillus cereusy Escherichia coli, other virulence properties, such as enteroinvasive (EIEC), enteropathogenic

(EPEC), enterotoxigenic (ETEC), enteroaggregative (EAEC or EAgEC)

y Listeria monocytogenesy Shigella spp.y Staphylococcus aureusy Streptococcusy Vibrio cholerae, including O1 and non-O1y Vibrio parahaemolyticusy Vibrio vulnificusy Yersinia enterocolitica and Yersinia pseudotuberculosis

Less common bacterial agents:

y Brucella spp.y Corynebacterium ulceransy Coxiella burnetiior Q fevery Plesiomonas shigelloides

[edit] Exotoxins

In addition to disease caused by direct bacterialinfection, some foodborne illnesses arecaused by exotoxins which are excreted by the cell as the bacterium grows. Exotoxins canproduce illness even when the microbes that produced them have been killed. Symptomstypically appear after 16 hours depending on the amount oftoxin ingested.


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y C o d u bo u nu y C o d u p ng n y Staph o o u au u y Ba ! " " u# $ % $ u#

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) l0 1 0 1 1 2 3 & 2 4 5 2 3 produces a toxin that causes intense vomiting. The rare

but potentially deadly disease botulism occurs when the anaerobic bacterium Cl0 3

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0 t2 li 8 2 6 grows in improperly canned low-acid foods and produces botulin, a powerfulparalytic toxin.

Pseudoalteromonas tetraodonis, certain species ofPseudomonas and Vibrio, and some otherbacteria, produce the lethal tetrodotoxin, which is present in the tissues of some living animalspecies rather than being a product ofdecomposition.

[edit] Mycotoxins and alimentary mycotoxicoses

The term alimentary mycotoxicoses refers to the effect of poisoning by Mycotoxins throughfood consumption. Mycotoxins sometimes have important effects on human and animal

health. For example, an outbreak which occurred in the UK in 1960 caused the death of100,000 turkeys which had consumed aflatoxin-contaminated peanut meal. In the USSRinWorld WarII, 5000 people died due to Alimentary Toxic Aleukia (ALA).

[9]The common

foodborne Mycotoxins include:

y Aflatoxins originate 9 from As @ ergillus parasiticus and Aspergillus flavus A They arefre

Buently found in tree nuts, peanuts, maize,sorghum and other oilseeds, including corn

and cottonseedsAThe pronounced forms ofAflatoxins are those ofB1,B2, G1, and G2,

amongst which Aflatoxin B1 predominantly targets the liver, which will result in necrosis,

cirrhosis, and carcinoma.[10][11]

In the US, the acceptable level of total aflatoxins in foods is

less than 20 g/kg,except for Aflatoxin M1 in milk, which should be less than 0.5 g/kg.[12]

The official document can be found at FDA's website.[13][14]

y Altertoxins are those ofAlternariol (AOH), Alternariol methyl ether (AME), Altenuene(ALT), Altertoxin-1 (ATX-1), Tenuazonic acid (TeA) and Radicinin (RAD), originated from

Alternariaspp. Some of the toxinscan be present in sorghum,ragi, wheat and

tomatoes.[15][16][17]

Some research hasshown that the toxinscan beeasilycross-

contaminated between grain commodities,suggesting that manufacturing and storage of

grain commodities is a critical practice.[18]

y Citrininy Citreoviridiny Cyclopiazonic acidy Cytochalasinsy Ergot alkaloids / ErgopeptinealkaloidsErgotaminey FumonisinsCrop corn can beeasilycontaminated by the fungi Fusarium moniliforme, anditsFumonisin B1 will cause Leukoencephalomalacia (LEM) in horses, Pulmonaryedema

syndrome (PES) in pigs, liver cancer in rats and Esophageal cancer in humans.[19][20]

For

human and animal health, both theFDA and theEC have regulated thecontent levels of

toxins in food and animal feed.[21][22]

y Fusaric acidy Fusarochromanoney Kojic acidy Lolitrem alkaloidsy Moniliformin


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y 3-Nitropropionic acidy Nivalenoly Ochratoxins In Australia, The Limit of Reporting (LOR) level for Ochratoxin A (OTA) analyses

in 20th Australian Total Diet Survey was 1 g/kg,[23]

whereas the EC restricts the content of

OTA to 5 g/kg in cereal commodities, 3 g/kg in processed products and 10 g/kg in dried

vine fruits.[24]

y Oosporeiney Patulin Currently, this toxin has been advisably regulated on fruit products. TheEC and the

FDA have limited it to under 50 g/kg for fruit juice and fruit nectar, while limits of 25 g/kg

for solid-contained fruit products and 10 g/kg for baby foods were specified by theEC.[24][25]

y Phomopsinsy Sporidesmin Ay Sterigmatocystiny Tremorgenic mycotoxins Five of them have been reported to be associated with molds

found in fermented meats. These are Fumitremorgen B, Paxilline,Penitrem A, Verrucosidin,

and Verruculogen.[26]

y Trichothecenes sourced from Cephalosporium,Fusarium, Myrothecium,Stachybotrys andTrichoderma. The toxins are usually found in molded maize, wheat, corn, peanuts and rice,

or animal feed of hay and straw.

[27][28]

Four trichothecenes, T-2 toxin, HT-2 toxin,diacetoxyscirpenol (DAS) anddeoxynivalenol (DON) have been most commonly encountered

by humans and animals. The consequences of oral intake of, or dermal exposure to, the

toxins will result in Alimentary toxic aleukia,neutropenia,aplastic anemia,

thrombocytopeniaand/or skin irritation.[29][30][31]

In 1993, the FDA issued a document for the

content limits of DON in food and animal feed at an advisory level.[32] In 2003, US published a

patent that is very promising for farmers to produce a trichothecene-resistant crop.[33]

y Zearalenoney Zearalenols

[edit] Emerging foodborne pathogens

Many foodborne illnesses remain poorly understood. Approximately sixty percent ofoutbreaks are caused by unknown sources.[citation nee

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eC

]

y Aeromonas hydrophila,Aeromonas caviae,Aeromonas sobria[edit] Preventing bacterial food poisoning

Proper storage and refrigeration offood help in the prevention of food poisoning


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Prevention is mainly the role ofthe state, through the definition of strict rules ofhygiene anda public services ofveterinary surveying of animal products in the food chain, fromfarmingto the transformation industry and delivery (shops andrestaurants). This regulation includes:

y traceability: in a final product, it must be possible to know the origin of the ingredients(originating farm, identification of the harvesting or of the animal) and where and when it

was processed; the origin of the illness can thus be tracked and solved (and possiblypenalized), and the final products can be removed from the sale if a problem is detected;

y enforcement of hygiene procedures likeHACCP and the "cold chain";y power of control and of law enforcement ofveterinarians.

In August 2006, the United StatesFood and Drug Administration approvedPhage therapywhich involves spraying meat with viruses thatinfect bacteria, and thus preventing infection.

This has raised concerns, because withoutmandatory labelling consumers wouldn't be awarethat meat and poultry products have been treated with the spray. [1]

At home, prevention mainly consists of goodfood safety practices. Many forms of bacterialpoisoning can be prevented even if food is contaminated by cooking it sufficiently, and either

eating it quickly or refrigerating it effectively[citation neeD

eD

]. Many toxins, however, are notdestroyed by heattreatment.

[edit] Viruses

Viralinfections make up perhaps one third of cases of food poisoning in developed countries.In the US, more than 50% of cases are viral and noroviruses are the most common foodborneillness, causing 57% of outbreaks in 2004. Foodborne viralinfection are usually ofintermediate (13 days) incubation period, causing illnesses which are self-limited inotherwise healthy individuals, and are similarto the bacterial forms described above.

y Enterovirusy Hepatitis A is distinguished from other viral causes by its prolonged (26 week)incubation

period and its ability to spread beyond the stomach and intestines, into theliver. It often

induces jaundice, or yellowing of the skin, and rarely leads to chronic liver dysfunction. The

virus has been found to cause the infection due to the consumption of fresh-cut produce

which has fecal contamination.[34][35]

y Hepatitis Ey Norovirusy Rotavirus


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Rotavirus

[edit] Parasites

Most foodborne parasites are zoonoses.

y Platyhelminthes:o Diphyllobothrium sp.o Nanophyetus sp.o Taenia saginatao Taenia solium

The scolex ofTaenia solium

o Fasciola hepaticaSee also: Tapeworm andFlatworm

y Nematode:o Anisakis sp.o Ascaris lumbricoideso Eustrongylides sp.o Trichinella spiraliso Trichuris trichiura

y Protozoa:o Acanthamoeba and other free-living amoebaeo Cryptosporidium parvumo Cyclospora cayetanensiso Entamoeba histolyticao Giardia lamblia


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[edit] Natural toxins

Several foods can naturally contain toxins, many of which are not produced by bacteria.Plants in particular may be toxic; animals which are naturally poisonous to eat are rare. Inevolutionary terms, animals can escape being eaten by fleeing; plants can use only passivedefenses such as poisons and distasteful substances, for example capsaicin in chili peppersand pungent sulfurcompounds in garlic and onions. Most animal poisons are not synthesisedby the animal, but acquired by eating poisonous plants to which the animal is immune, or bybacterial action.

y Alkaloidsy Ciguatera poisoningy Grayanotoxin (honey intoxication)y Mushroom toxinsy Phytohaemagglutinin(red kidney bean poisoning; destroyed by boiling)y Pyrrolizidine alkaloidsy Shellfish toxin, including paralyticshellfish poisoning, diarrheticshellfish poisoning,

neurotoxicshellfish poisoning,amnesicshellfish poisoning and ciguatera fish poisoning

y Scombrotoxiny Tetrodotoxin (fugu fish poisoning)

Some plants contain substances which are toxic in large doses, but have therapeuticproperties in appropriate dosages.

y Foxglovecontainscardiac glycosides.y Poisonous hemlock (conium) has medicinal uses.

[edit] Other pathogenic agents

y Prions, resulting in Creutzfeldt-Jakob disease[edit] "Ptomaine poisoning"

An early theory on the causes of food poisoning involved ptY ` a ib c d (from Greekpt` a ,"fall, fallen body, corpse"), alkaloids found in decaying animal and vegetable matter. While

some alkaloids do cause poisoning, the discovery of bacteria left the ptomaine theoryobsolete and the word ptY ` a ib c is no longer used scientifically.


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y YersiniaInfants and elderly people are at the greatest risk for food poisoning. You are also at higherrisk if:

y You have a serious medical condition,such as kidney disease or diabetesy You have a weakened immunesystemy You travel outside of the United States to areas where there is moreexposure to organisms

that cause food poisoning

Pregnant and breastfeeding women have to be especially careful to avoid food poisoning.


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Whatis food poisoning?

Food poisoning is an unpleasant illness which is caused by eating contaminated food. Thisincludes food which has been poorly prepared, cooked at the wrong temperature or as a resultof poor hygiene. It can also occur if raw food is stored next to cooked food.

This contamination includes bacteria, viruses, toxins or parasites.

This is a common illness which ranges from relatively mild through to serious, even lifethreatening conditions. The degree of severity of food poisoning will depend upon the cause.

Whatever the extent, food poisoning is a horrible illness which most of us have experiencedat some point in our lives.

According to the Food Standards Agency (FSA) there are nearly 900, 000 cases of food

poisoning each year. However, this figure may be higher due to the fact that not every case offood poisoning is reported.

(Source: NHS Choices: food poisoning)

So, food poisoning is more common than we realise.

Increase in the number of cases of food poisoning

Food poisoning is not only a common illness but one which appears to be on the increase.

Why is this?

There are two reasons for this:

y Changing lifestylesy Global food market

Changing lifestyles

Our lifestyles have changed over the last few years which include an increasing reliance onready prepared meals, eating out rather than cooking and taking more holidays abroad.

We all lead busy lives and as a result of that tend to spend less time preparing and cookingfood. People often cook several meals in advance and freeze them for a long period of time or

buy convenience food which only has to be put in a microwave oven.

Another popular option is buying takeaway meals. It is a quick option with the minimum offuss and offers a wide variety of choice.

But with this increased choice and flexibility comes an increase in health risks. Foodpoisoning occurs if food is not stored in the refrigerator at the correct temperature or is keptpast its sell bydate. Another problem is when food is reheated even though it is not designedto be or is not cooked for the right amount of time.


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This applies to food bought for consumption at home, from a local fast food outlet or arestaurant.

Another factor is that women as well as men go out to work which means that they have less

time (and inclination!) to cook a meal. At one time the woman stayed at home and had a mealready for her family once they arrived home from work and school but that is less common

nowadays.

If you are tired after a long day at work then the last thing you want to do is to spend hourspreparing a meal when it is so much easier to put something in the microwave.

This combined with the fact that cookery is not as widely taught as it used to be has led to adecrease in basic cooking skills.

However, there has been a swing back to what are considered old fashioned cooking skillswhich is largely due to the current economic climate. People are having to cut back and arelooking at ways of reducing their outgoings which often includes staying in and cookingrather than eating out or buying ready made meals.

This may reduce the number of food poisoning cases.

Global foodmarket

Another reason is our global village: we are able to access a greater range of foods thanbefore which are flown in from all parts of the world.

But these foods are often from countries which have different standards of food safety fromthe UK which means that it is easy for bacteria to quickly spread from one host to another.

Many of us have become accustomed to purchasing foods out of season, for examplestrawberries which be bought in winter rather than the summer. We expect to walk into asupermarket and purchase these foods whenever we want and dont always give this a second

thought.

But whilst it is ideal to have a wide range of choice there is an increased risk of contractingfood poisoning due to variable food standards.

However there is a trend towards buying locally produced food or foods which are in seasonwhich might help alleviate this problem. Plus this also supports local growers which isbeneficial for the economy.

Knowing where your food is sourced from and the standards of care and safety that have beenapplied may help to reduce the incidences of food poisoning.

Whatcauses food to become contaminated?

Many cases of food poisoning can be attributed to poor food hygiene. Food which has notbeen properly prepared, cooked or stored becomes a ripe breeding ground for bacteria whichmultiply and then release toxins which are absorbed by the body.


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These toxins cause the characteristic symptoms of food poisoning which are nausea, stomachpains, vomiting and diarrhoea. These symptoms develop quickly, often within 48 hours.

This is discussed in more detail in ourbacterial food poisoning section.

Contamination and cross-contamination are the two main causes of food poisoning. Both of

these are discussed in greater detail in ourcauses of food poisoning section.

Food can also be contaminated by viruses and pesticides. Viruses, for example norovirus are

known for causing food poisoning, especially in areas where large numbers of peoplecongregate, e.g. on board a cruise ship.

Find out more in ourviral food poisoning section.

Pesticides are substances sprayed onto crops to protect them against pests, for exampleinsects or weeds. However, there are risks to health from using these which includessymptoms of food poisoning.

Find out more in ourtoxins section of this guide.

To summarise: most but not all cases of food poisoning are caused by infected food.However, food poisoning can be caused by viruses spread by person to person contact orclose proximity to an infected animal.

Food poisoning also occurs from drinking water which has been infected with bacteria orparasites such as giardia.

So whilst contaminated food is the most likely cause of food poisoning, do not discount thepossibility of it being caused by a virus, parasite or toxin.


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Aspects of food poisoning

y Caused bycontaminated food and/or watery Spread by theconsumption of any infected food producty Causes abdominal pain, nausea,vomiting and diarrhoeay Can lead to dehydration, kidney failure and reactive arthritis in severecases.

Food poisoning occurs when a food product is consumed which is contaminated by bacteria.These bacteria attach themselves to the lining of the intestines and start to multiply. Toxinsare then released which attack cells within this lining that results in the symptoms describedabove.

These toxins can be absorbed by the body which may cause problems elsewhere.

So, food poisoning occurs due to the bacteria in the contaminated food and the toxinsproduced.

Foods whichare likelyto cause food poisoning

Food poisoning is caused by the consumption of food which has been contaminated bybacteria or other similar toxins. However, there are certain foods which carry a greater riskfor food poisoning than others.

These foods include:

y Poultry,e.g. chickeny Eggsy Red meaty Porky Cooked rice/pastay Coleslawy Unpasteurised milky Shellfishy Unwashed fruit and vegetables

Other groups include ready-to-cook foods such as those found in chiller cabinets insupermarkets. These include pre-packaged sandwiches, cooked meats (e.g. salami), pates andsoft cheeses such as Brie.

A major risk with this group of foods is listeria: this type of bacteria is found within thesefoods and is especially risky to pregnant women, babies and people with a weakened immunesystem.


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Listeria is discussed further in our bacterial food poisoning section.

food poisoning overview

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