Gastroenteritis

Gastroenteritis is the inflammation of intestines and stomach. The symptoms can include diarrhea, stomach pain, nausea, vomiting, fever or feeling unwell. It could be persistent, acute, or chronic, and can also be classified as infectious or non-infectious.

Diarrhea is defined as the passage of three or more loose or watery stools per day (or more frequent passage of stool than is normal for the individual). Sometimes diarrhea is so severe that a person becomes very ill and loses large amounts of body fluids.

There are three clinical classifications of diarrheal conditions:
• Acute diarrhea, lasting several hours or days
• Acute bloody diarrhea or dysentery
• Persistent diarrhea, lasting 14 days or longer

The three major types of germs that cause gastro are bacteria, viruses and parasites. While most of these are usually harmless, many can cause illness in some situations.

Gastro can also be caused by toxins that some bacteria produce in food (for example Staphylococcus aureus, Clostridium perfringens).

It is quite challenging to establish accurate incidence and prevalence of acute gastroenteritis because of under-reporting of attacks by many patients. Moreover, only 1.5% of stool samples get positive results for a bacterial cause.

Viral infection that affects the stomach and small intestine is called stomach flu. The illness is usually brief, lasting 1 to 3 days. Norovirus and Rotavirus are the most common causes of viral gastroenteritis. Reports suggest that up to twenty-five million cases of acute viral gastroenteritis occur annually in the United States.

The virus enters the stomach and intestine and inflames the lining of these organs. As a result, the stomach and intestine are temporarily unable to perform their usual functions.

The most important causes of bacterial gastroenteritis in Europe have been reported to be enteroaggregative E. coli (EAEC), Campylobacter, and enteropathogenic E. coli. A study in 2012 has concluded that Campylobacter was responsible for more cases of chronic gastroenteritis than Salmonella, with an incidence of 68 vs. 22 cases per 100,000.

Germs that cause gastroenteritis are usually spread by contamination of something that goes in human mouth. This can occur by contact with contaminated objects, including food or water, or by contact with other people who are ill.
Gastroenteritis

Temperature 40°F and below inhibits the growth of Salmonella

Salmonella is the most common form of food poisoning, causing vomiting, fever, and stomach pain. There re actually three types of disease caused by Salmonella: Enteric fever caused by S. typhosa; septicemia caused by S. cholerasuis; and gastrointeritidis caused by S typhimurium and S. enteritidis.

Salmonellae in foods are destroyed by heating the food to at least 160° F for red meats and 185° F for poultry. In general, foods heated to an end-point temperature of 160°F or above will destroy Salmonella.

All foods should be held at temperatures of 4.4 °C or below when not being cooked, prepared for cooking or being served. This would not eliminate Salmonella organisms from foods, but it would prevent their growth in the foods so that their number would be too small to cause salmonellosis in healthy adults.
Temperature 40°F and below inhibits the growth of Salmonella

Strain of Escherichia coli O157:H7

Although most kinds of E. coli bacteria do not cause disease in humans, those that are pathogenic are a significant threat to public health, especially relating to food safety.

The most common and notorious of these pathogenic bacteria are E. coli O17:H7, which part of a category call enterohemorrhagic E. coli (EHEC).

Escherichia coli O157:H7 was first identified as a human pathogenic in 1982. A rare but dangerous type of E. coli, the strain O157:H7 is now a major public health problem worldwide.

The main method of identifying pathogenic strains of E coli has been stereotyping base on specific markers found on the bacterial cell surface, namely the O, H and K antigens. The “O” antigen of E. coliO157:H7 was the 157th cell surface lipopolysaccharide or somatic antigen, to be identified; the ”H” antigen was the seven flagellar antigen identified.

The major reservoir of E. coli O157:H7 are ruminant animal, particularly cattle. E. coli O157:H7 has also been isolate from sheep, deer, and goats. E. O157:H7 was identified as the cause of two outbreaks of hemorrhagic colitis that occurred in 1982 and were associated with undercooked ground beef.
Strain of Escherichia coli O157:H7

Acute gastroenteritis

Acute gastroenteritis is characterized by stomach and intestinal mucosal inflammation secondary to viral or bacterial infection, food poisoning, chemical irritants or food allergies.

The most common etiology of gastroenteritis is foodborne infections. The most common culture-confirmed infections were Salmonella, followed by Campylobacter and Shigella.

Regardless of the source, patients often present complaining of some combination of anorexia, nausea, abdominal pain, vomiting, diarrhea and dysentery (bloody diarrhea), and fever

Vomiting may prevent oral intake, leading rapidly to dehydration, especially when diarrhea contributes to fluid losses. Diarrhea may be debilitating or fatal even in the absence of vomiting.

In term of virus, Norwalk virus are the most common cause of infectious acute gastroenteritis and are transmitted feco-orally through food and water directly from person to person and by environmental contamination.

These viruses are often responsible for protracted outbreaks in closed stetting, such as cruise ships, nursing homes and hospitals. Norwalk virus alone is estimated to account for more than half of cases of gastroenteritis.
Acute gastroenteritis

Foodborne illness due to bacterial food poisoning

Foodborne illness, one of the greatest public health and food industry concerns.

In some infections, microbes produce toxins inside the infected person’s body. In food poisoning cases, the microbes produce toxins the contaminated food and when people eat the food, the toxins make them very ill.

If a person eats food containing a fairly large amount of a toxin, it is like that he or she will be ill that day.

The disease is characterized by rapid onset, severity of symptoms, but usually a short duration.

Examples include botulism due to the formation of botulinum toxin in the food from the growth of certain clostridial species, staphylococcal and histamine poisoning.

Where these toxic food poisonings result from bacterial toxins, the poisons are synthesized in the food. 

Today, staphylococcal food poisoning ranks as the second most reported of all types of foodborne disease. Because most staphylococcal outbreaks probably t unreported, staphylococcal food poisoning could actually be the most common type.

Symptoms of foodborne illness are diarrhea, nausea, abdominal pain or vomiting without fever or upper respiratory distress.

Most foodborne illnesses are caused by the mishandling of food or the faulty cooking or storage of food, either in food service establishment or at home.
Foodborne illness due to bacterial food poisoning

Autoimmune disorders foodborne infection

Consumers are often unaware that there are long-term as well as short term consequences of foodborne microbial disease.

Several foodborne bacteria including staphylococcus, streptococcus, Yersinia and clostridium have superantigens.

Many of these are thought to be associates with several autoimmune disorders such as rheumatic heart disease, rheumatoid arthritis, multiple sclerosis, Grave disease and Crohn disease.

What are autoimmune disorders? Autoimmune disorders are disease caused by the body producing an inappropriate immune response against its own tissue.

Normally, the immune system should be able to distinguish between ‘self’ and ‘not self’ and only attacks those tissues that it recognizes as ‘not self’.

Graves disease is an autoimmune thyroid disease mediated by autoantibodies to the thyrotropin receptor. The disease may be inked to an infection with Y. enterocolitica serotype 0:3.

Campylobacter jejuni leads to a serious autoimmune disorder that affects peripheral nervous system resulting in flaccid paralysis called Guillain-Barre syndrome.
Autoimmune disorders foodborne infection

Common causes to food borne illness

A foodborne disease is any illness caused by eating food. A food borne disease outbreak is when two or more people have the same illness.

Some food-handling errors introduce pathogens into uncontaminated food. This including: use contaminated food, cross contamination, poor personal hygiene, inadequate cleaning of requirement, inadequate cooking, insufficient process such as fermentation, acidification or salting.

The most common error cause by mass outbreaks reported to CDC was improper holding temperature.

In countries with poor sanitary conditions, diarrheal illness is a leading cause of mortality and malnutrition in young children.

While most infections are acquired from contaminated drinking water, food is an important route of transmission.

Common bacterial causes of foodborne illness are Salmonella, Listeria monocytogenes, Shigella, Staphylococcus aureus, Clostridium perfringens, Bacillus cereus, Escherichia coli.

Nontyphoidal Salmonella and Campylobacter were estimated to be leading causes of foodborne illness in Australia, England, and Wales and the United States.

In recent years, norovirus have been the most common cause of foodborne illness.

Bacterial pathogens can be easily transmitted and can multiply rapidly in food, making them difficult to control. While, the chemical causes of foodborne illnesses are primarily natural toxins that occur in fish or other foods but also include heavy metals, such as copper and cadmium.
Common causes to food borne illness

Microbial Grouping

Microbial Grouping
The microbial groups important in foods consist of several species and types of bacteria, yeasts, molds and viruses. Bacteria, yeasts, molds and viruses are important in food for their ability to cause foodborne diseases and food spoilage to produce food and food ingredients.

Many bacterial species and some molds and viruses, but not yeasts are able to cause foodborne disease.

Most bacteria, molds and yeasts, because of their ability to grow in foods (viruses cannot grow in foods, can potentially cause food spoilage.

Several species of bacteria, molds and yeasts are considered safe of food grade or both and are used to produce fermented foods and food ingredients.

Among the four major groups, bacteria constitute the largest group. Because of their ubiquitous presence and rapid growth rate even under condition where yeast and molds cannot grow, they are considered the most important in food spoilage and foodborne disease.

Prion or proteinaceous infectious a particles have been identified to cause transmissible spongiform encephalopathies (TSEs) in humans and animals.
Microbial Grouping

Favorable growth conditions for bacteria

Favorable growth conditions for bacteria
Microorganisms grow when they have the right nutrients and conditions for growth. Bacteria need these conditions to grow:

Food
High protein foods are often contaminated at the time of purchase. Using safe food practices destroys the bacteria. Acidity: bacteria prefer low-acid environments. Some bacteria do survive an acidic environment.

Bacteria use an enormous range include various sugars and either carbohydrates, amino acids, sterols, alcohols, hydrocarbons, inorganic salts and carbon dioxide.

Time
Potentially hazardous foods should not remain in the danger zone for more than four hours during the entire food handling process.

Temperature
The temperature danger zone is 40 degrees F to 140 degrees F.

Oxygen
Many bacteria grow bets in the present of oxygen (aerobic organism). Some bacteria grow without oxygen- anaerobic. However, both types of bacteria cause foodborne illness.

Others grow equally well under either aerobic or anaerobic conditions.

Moisture
Bacteria grow best in a moist environment.
A high proportion of the mass of a bacterium is water, and during growth, nutrients and waste products enter and leave the cell. Bacteria can grow only in or on materials which have adequate free or available water.

pH
Most bacteria grow best at near pH7 (neutral), and the majority cannot grow under strongly acidic or strongly alkaline solution.
Favorable growth conditions for bacteria

Food Spoilage

Food Spoilage
Processed and natural foods are composed mainly of carbohydrates proteins and fats.

The major constituents in vegetables and fruits are carbohydrates, including sugars (sucrose, etc), polymers of sugars (starch) and other complex carbohydrates such as fibers.

Fats are the major components of milk and most cheeses, and proteins are the chief constituents of muscle foods.

Under natural storage conditions, foods start to deteriorate once the living cells in the foods (plant and animal origins) are dead.

Either when the cells are dead or if the tissues are damaged, deterioration begins with the secretion of internal proteases (such as chymotrypsin and trypsin to break up proteins at specific amino acid positions), lipases and lyases from lyzosomes to disintegrate the cells, to hydrolyze proteins into amino acids and starch into simpler sugars (or monosaccharides), and to de-esterificate fats ( triglycerides) into fatty acids.

The exposure of foods and damaged cells to the environment attracts microorganisms (e.g. bacteria, molds and virus) and insects, which in turn further accelerate the decomposition of the food.

For most food poisoning, spoilage has not reached the stage where the sensory attributes (appearance, smell, taste, texture, etc.) of the food are abnormal.

Illness form food can be mainly classified as:

• Food borne infection caused by pathogenic bacteria (disease-causing microorganisms, such as Salmonella bacteria, multiplying in victim’s digestive tract causing diarrhea, vomiting and fever, etc.)
  
• Food borne intoxication (food poisoning resulting from toxin produced by pathogenic microorganisms, e.g. Clostridium botulinum and Staphylococcus aureus, in the digestive tract).
  

Food borne illness also has a major economic impact on society, costing billions of dollars each year in the form of medical bills, lost work time, and reduced productivity.
Food Spoilage

Bacterial Food Poisoning

Bacterial Food Poisoning
The following bacteria frequently cause food poisoning:

• Salmonella
• Staphylococcus aureus
• Clostridium perfringes
• Bacillus cereus
  
  The following bacteria cause food poisoning less frequently:
• Clostridium botulinum
• Some strains of Escherichia coli
  
  

All bacteria have two names. The generic name is written first and with a capital letter, e.g. Clostridium, Bacillus.

The specific name is written with a small letter after generic name, e.g. perfringes, cereus.

Bacteria with the same generic name have similar characteristics, e.g. shape, oxygen requirements, enterotoxin production and spore formation.

There are approximately 2000 species of the Salmonella genus (e.g. Salmonella typhimurium, Salmonella enteriditis, Salmonella hadar, Salmonella newport) but most of them cause food poisoning it is usual to talk about Salmonella food poisoning without distinguishing which species is actually cause.

Salmonella, Staphylococcus aureus, Clostridium perfringes and Bacillus cereus are all common cause of food poisoning in the UK and many other countries.
Bacterial Food Poisoning

Bacteria in General

Bacteria in General
Bacteria are single celled organisms that can cause foodborne illness in two ways

1. They can infect foods themselves, by their presence in the food as they feed on it
2. They can produced toxins, which can make food hazardous, as they breakdown. Bacteria, under good condition, can grow and divide quickly – each cell dividing into two approximately every 20 minutes.
   

Good conditions for bacterial growth require

• Food – especially high protein

• Acidity – neutral to low acid

• Temperatures –especially 40 – 140 degree F, ideal temperature is 90 to 100 degree F about body temperature

• Oxygen

• Moisture

When one or more of these six factor is present in a food product, creating the conditions for bacterial growth, that food product is a potentially hazardous food. Potential hazardous foods therefore include meats; poultry; fish; soy-based foods; eggs; milk and milk products; cooked pasta, rice, potatoes, or beans; garlic oil mixture; raw fruits and vegetables; and raw seeds and sprouts. Some of these items surprise many people – it’s not the mayonnaise that is the problem on a buffet; rather, it is the moisture content and low acidity of the items that are put into mayonnaise – potatoes, pasta, beans, etc. Some bacteria even produce spores that don’t reproduce but can survive heating and cooling so that as conditions improve the spore’s bacteria can become active again.
Bacteria in General

Health effects of E. coli O157:H7

Health effects of E. coli O157:H7
E. coli O157:H7 is one of hundreds of strains of the bacterium E. coli. Although most strains are harmless and live in the intestines of healthy humans and animals, this strain produces a powerful toxin and can cause severe illness.

Infection often causes severe bloody diarrhea and abdominal cramps; sometimes the infection causes non-bloody diarrhea. Frequently, no fever is present. It should be noted that these symptoms are common to a variety of diseases, and may be caused by sources other than contaminated drinking water.

In some people, particularly children under 5 years of age and the elderly, the infection can also cause a complication called hemolytic uremic syndrome, in which the red blood cells are destroyed and the kidneys fail. About 2%-7% of infections lead to this complication.

In the United States, hemolytic uremic syndrome is the principal cause of acute kidney failure in children, and most cases of hemolytic uremic syndrome are caused by E. coli O157:H7. Hemolytic uremic syndrome is a life-threatening condition usually treated in an intensive care unit. Blood transfusions and kidney dialysis are often required. With intensive care, the death rate for hemolytic uremic syndrome is 3%-5%.
Health effects of E. coli O157:H7