General view of bacterial toxin

Toxins are powerful pathogenicity factors produced by certain bacteria, fungi, animals, and plants which mediate drastic interactions of these pathogens on the organism host. Notably, bacterial toxins were the first compounds which were identified as responsible for severe bacterial diseases in man and animals.

Bacterial toxigenesis is a major mechanism by which pathogenic bacteria produce diseases. They produce two kinds of toxins, lipopolysaccharides and protein toxins. Lipopolysaccharides are cell-associated toxins released after disruption of the cell (endotoxins), whereas protein toxins are synthesized inside the cells and then released to the target cells.

Endotoxins are associated with Gram-negative bacteria and form part of their cell wall structures. More specifically, endotoxins refer to the lipopolysaccharide complex associated with the outer membranes of Gram-negative bacteria.

The toxins are usually liberated from the organism by lysis, but some are shed with outer membrane proteins in outer membrane vesicles.

Bacterial toxins are the most powerful poisons produced in the nature, and are known to retain a very high level of activity at high dilutions. Bacterial toxins proteins capable of achieving multiple remarkable tasks. They function as autonomous molecular devices, targeting specific cells in an organism, punching holes in their membranes, or modifying intracellular components. Intoxication processes involve highly specialized steps of great complexity.

Toxins may damage the eukaryotic cell mem brane by combining with some structural component, or otherwise alter its function. Many toxins combine with specific receptors on the surface membrane, frequently glycoproteins or gangliosides, and penetrate the cell to reach their intracellular target. A common mechanism of entry is absorptive endocytosis.

Structurally, bacterial toxins seem to display some unconventional strategies. For example, toxins may have structurally and functionally identical domains but containing different binding domains (Diphtheria toxin and Pseudomonas ExoA), or could have similar binding domains but different catalytic domains.
General view of bacterial toxin

Food intoxications

A wide variety of foods and food products derived from plants and animals support the growth of pathogenic and toxigenic bacteria, resulting in food-borne diseases such as food infection and food intoxication or poisoning which is a major public health problem globally.

Food intoxication is a form of food-borne illness caused by ingesting exotoxins made by organisms such as bacteria, fungi etc or by consuming the foods that are naturally toxic to humans and animals. Bacterial growth and toxin production in foods are influenced by various intrinsic (e.g. pH, moisture, redox potential, nutrients) and extrinsic (e.g. temperature) factors.

Toxins can cause food-borne diseases such as gastrointestinal and systemic disorders. Toxins, not bacteria, cause illness. Toxins may not alter the appearance, odor or flavor of food. Common kinds of bacteria that produce toxins include Staphylococcus aureus and Clostridium botulinum.

The intoxication usually comes with an abrupt and violent onset of vomiting, nausea, cramps, and exhaustion, often accompanied by diarrhea and low-grade fever, and sometimes, low blood pressure. Symptoms occur between 1 to 8 hours after ingestion of enterotoxin, but usually between 2 to 4 hours.

In the case of Clostridium perfringens, illness is caused by toxins released in the gut when large numbers of vegetative cells are eaten.

Any person can get intoxication, which is widespread and relatively frequent. About 25% of U.S. population is carriers of Staphylococcus aureus.

Food intoxications

Toxin in our beverages

People are always reminded to refrain from consuming too much sodas and softdrinks because they contain lots of sugar and can cause tooth decay. But never because they contain benzene.

In 2001, an Italian survey was conducted to determine benzene in 60 beverages. Benzene was detected at low concentrations in all the samples. Regular and diet softdrinks, orange juice and carbonated orange juice were analyzed and found to contain benzene amounts that ranges from 0.7 to 2.9 ppb.

Benzene is not in the product as produced, but it can form due to a reaction that occurs between certain ingredients used to preserve and flavor the drinks.

It has been established that the source of benzene in softdrinks is the decarboxylation of benzoic acid when ascorbic acid and trace amounts of a suitable metal catalysts (copper or iron) are present.

This now posed a new barrage of health and medical concerns and debates.

Benzene is carcinogen which is used in production of plastics, detergents and pesticides. It is produced naturally by the burning of natural products. Benzene has caused leukemia to develop in people which have bee exposed to it.

Benzene is produced from petrochemicals and is used as an engine antiknock agent in gasoline.
It does not matter whether the benzene concentration is negligible or not, but the fact that it is in there and it is significant enough to be detected, should alert health and medical professionals.

It is also imperative that consumption of softdrinks found with benzene should be stopped or else limited to adults since benzene can stunt the growth of the mental and physical faculties of children.

Beverage producers are now reformulating the ingredients to avoid the reaction. Many drinks have now replaced potassium benzoate in drinks with potassium sorbate.

However, for several years millions of us swallowed benzene in softdrinks without our knowledge.

Lastly, perhaps it is better to limit intake of processed foods and beverages to ensure that less chemicals enter and pollute the body systems.

Food safety should be a top priority for consumers and manufacturers alike. It is also wise to act on anything that raise health and medical problems immediately to avoid further complications.
Toxin in our beverages

Food Intoxication: Staphylococcal Poisoning

The symptoms of staphylococcal poisoning are nausea, vomiting, abdominal cramps, diarrhea, and prostration. While the symptoms last, suffering may be acute, but this is usually for period of only a few hours.

Intoxication are especially important because the preformed toxin may remain in the food if resistant to inactivation.

Diarrhea is uncommon in staphylococcal intoxication. Food poisoning strains of Staphylococcus aureus produce a heat stable enterotoxin that has a direct effect upon the central nervous system.

Generally, the patient recovers without complications. The incubations period after ingestion or eating food containing the toxin is from 1 to 7 hours, usually 3 tom 6 hrs.

Staphylococcal poisoning is often wrongly called ptomaine poisoning.

Ptomaine poisoning, may be developed from taking into the system food that is in a state of decomposition which produced a bacteria or it may be produced by taking wholesome food into the system in too large quantities.

Staphylococcus aureus
Staphylococcus food poisoning is associated most frequently with coagulase-positive Staphylococcus aureus. It is the same bacterium that causes white-head pimples, infections, boils and carbuncles.

These cells are spherical or ovoid in shape, non motile and in liquid cultures, arrange themselves in grapelike clusters, in small groups, pairs, or in short chains.

They grow best in the presence of air but they will also grow in the absence of air. They will grow in media or in foods that contain as much as 10% salt. When these organisms grow in foods they produce a toxin that can be filtered away from the food and from the bacterial cells.

The toxin is not destroyed by cooking. Heating destroys competing microflora and denatures proteins for use by the staphylococcus. It also provides a favorable temperature, for the staphylococci initiate growth at 45 degree on a cooling food.

Staphylococcus food poisoning is usually associated with meat including beef, chicken, ham and other pork products and turkey.

If food not properly stored before consumption, however, staphylococcus may flourish and produce sufficient exotoxin to cause disease.
Food Intoxication: Staphylococcal Poisoning