Bacillus cereus toxin

Bacillus cereus-triggered food poisoning manifests suddenly as the microorganism releases toxins, leading to two distinct categories of gastrointestinal disorders: an emetic syndrome characterized by vomiting, and a diarrheal syndrome.

In the emetic phase, individuals undergo severe and prolonged nausea, accompanied by recurring vomiting that usually persists for hours to days. This emetic syndrome occurs due to the ingestion of a cyclic peptide toxin called cereulide, which forms within the food during the growth of B. cereus.

Symptoms of diarrheal-type food poisoning caused by B. cereus encompass abdominal discomfort, watery diarrhea, rectal tenesmus, moderate nausea often accompanying diarrhea, sporadic vomiting, and the absence of fever.

B. cereus has the potential to flourish in improperly stored food. Hence, it becomes imperative to adopt suitable food handling practices, especially post-cooking, to prevent illnesses arising from this microorganism.

The diarrheal form of food poisoning arises from the presence of complex enterotoxins emerging during the vegetative growth of B. cereus in the small intestine. In contrast, the emetic toxin is produced by multiplying cells present in the food itself. In both variations of food poisoning, the implicated food generally undergoes heat treatment, with the enduring spores acting as the source of the poisoning.

Uncooked rice can house B. cereus spores, which can persist even through the cooking process. When rice is left at room temperature, these spores can activate and develop into bacteria.
Bacillus cereus toxin

Foodborne botulism: Toxin and symptoms

Botulism is an uncommon yet severe disease characterized by the targeting of nerves by a toxin, resulting in breathing difficulties, muscle paralysis, and potentially fatal consequences. The toxin is produced by bacteria called Clostridium botulinum, and occasionally by Clostridium butyricum and Clostridium baratii.

Botulism can occur when food or wounds become contaminated. Additionally, it can arise when bacterial spores grow in the intestines of infants. In rare cases, botulism can also be caused by medical treatments or acts of bioterrorism.

In situations where foodborne botulism occurs, the harmful bacteria thrive and produce the toxin in oxygen-depleted environments. Consuming food contaminated with the botulinum toxin can result in foodborne botulism. Improperly canned, preserved, or fermented homemade foods are common sources of this type of botulism. While it is infrequent, store-bought foods can also become tainted with the toxin.

The World Health Organization (WHO) has identified botulinum toxin in various food items, including low-acid preserved vegetables like green beans, spinach, mushrooms, and beets; fish, including canned tuna, fermented, salted, and smoked fish; as well as meat products such as ham and sausage.

Symptoms of foodborne botulism usually appear within 12 to 36 hours after the toxin enters the human body. Botulism causes paralysis by affecting the nerves responsible for muscle stimulation and parts of the central nervous system. Initially, it impacts the nerves in the skull, leading to symptoms such as blurred vision, difficulty swallowing, double vision, stammering or stuttering, vocal disturbances, drooping eyelids, facial weakness, and weakness of the tongue. Subsequently, weakness progresses to the neck and arms, eventually affecting the respiratory and lower body muscles.
Foodborne botulism: Toxin and symptoms

Gram-positive anaerobic bacillus of Clostridium perfringens

Clostridia produce the highest number of toxins of any type of bacteria. Among Clostridium species, Clostridium perfringens is the largest toxin producer and also the most widespread, being found as part of the microbiota of animals and humans and in the soil.

Clostridium perfringens is an important anaerobic pathogen causing food-borne gastrointestinal (GI) diseases in humans and animals, often referred to as perfringens food poisoning. Humans become infected by transmission of the bacteria from cooked dishes, especially meat dishes. Contamination of the meat by the intestinal contents of slaughtered animals might serve as an important source of this pathogen to the food supply.

C. perfringens develops easily in complex peptone media but much less in defined media. Under optimal conditions it can double in 7 min.

This bacterium is a gram-positive anaerobic bacillus that is classified into five types according to the production of four major toxins: alpha (α), beta (β), epsilon (ε) and iota (ι).

In addition to the major toxins, it can produce more than 15 other known toxins. Some of these additional virulence factors, including enterotoxin, necrotic enteritis B-like toxin (NetB) and beta-2 toxin, have received more attention than others due to their role in the pathogenesis of C. perfringens-associated disease (CPAD) in humans and animals.

While outbreaks of C. perfringens are common, they do not become major headlines because the typical symptoms of the illness are mild, and deaths are extremely rare.

C. perfringens is a highly ubiquitous bacterium widely distributed in all types of environment (soil, sediments, sewage, slurry, carcasses, dust, the surfaces of plants, etc.). Healthy humans and animals can be carriers of C. perfringens in their digestive tubes.
Gram-positive anaerobic bacillus of Clostridium perfringens

Mycotoxins cause cancer

Mycotoxins are toxic secondary metablistes produced by filamentous fungi (molds). Mycotoxins are very powerful protein synthesis inhibitors, so they can affect the DNA, which is a problem in and of itself.

Because they affect the DNA, the cells start multiplying abnormally which can eventually develop into cancer. That mycotoxins can and do cause oesophageal cancer, kidney cancer, liver cancer, prostate cancer.

Fumonisins are carcinogenic mycotoxins by some Fusarium, primarily F. verticillioides growing in maize. At least 28 fumonisins (fumonisin B1, fumonisin B2, and fumonisin B3) analogs are now known and three of these occur naturally in maize world wide.

Fumonisins ingestion via feed prpeared from corn contaminated woth Fusarium could cause leukoencephalomalacia in horse, pulmonary oedema in pig, and liver cancer in rat.

The incidence of F. moniliforme is home grown corn has been correlated with human esophageal cancer rates in Transkei, southern Africa and in China. Corn naturally contaminated with F. moniliforme and associated with a field oubreak of LEM in horse in the US was also shown to be hepatocarcinogenic in rats.
Mycotoxins cause cancer

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

Vomiting due to food poisoning

Diarrhea, vomiting and abdominal pain are probably the most common symptoms of food poisoning. Food poisoning is a general term referring to illness, usually, vomiting, caused by contaminated food or water.

Vomiting or emesis is the forceful expulsion of gastric and intestinal contents through the mouth. The emetic type of food poisoning is characterized by nausea excessive salivation, pallor and sweating and vomiting within 0.5 – 6 hours after consumption of contaminated foods.

Occasionally, abdominal cramps and/or diarrhea may also occur. Duration of symptoms is generally less than 24 hours.

In the vomiting process the stomach divides into two sections and a deep inspiration is taken; then with a strong contraction of the diaphragm and abdominal muscles the stomach contents are regurgitated up via the esophagus.

If vomiting occurs only an hour or so after food consumption, it may be caused by Staphylococcus aureus or Bacillus cereus toxins. These enterotoxins are absorbed in the stomach and act via the central vomiting center.

Vomiting from gastro-enteric infections, for example salmonella or typhoid, can also be classed as food poisoning.
Vomiting due to food poisoning

Botulism toxin

Botulism is a rare but serious food borne disease caused by a nerve toxin that is produced by the bacterium Clostridium botulinum.

Botulism is characterized by symmetric descending flaccid paralysis resulting from the effect of botulinum neurotoxin.

Clostridium botulinum, the etiologic agent of botulism, is an anaerobic, spore forming organism that elaborates a neurotoxin that prevents the release of acetylcholine.

This poison spreads in dead plants or animal matter. It kills many those who make the mistake of eating it. The three main clinical presentations of botulism include infant botulism (IB), foodborne botulism (FBB) and wound botulism (WB).

Food borne botulism is caused by eating foods that contain the botulism toxin. It causes food poisoning because its heat resistant spores may survive food preservation methods and produce neurotoxin in anaerobic, low acid (pH>4.6) conditions.

Wound botulism, which is very rare, is caused by a toxin produced from a wound infected with C. botulinum. Infant botulism is caused by consuming the spores of botulinum bacteria, which grow in a child's intestines.

The botulinum toxin is a colorless, odorless, and tasteless protein that our digestive enzymes can’t break down. It is small enough to pass through the lining of the digestive tract to be absorbed into the blood stream.

Botulism toxin

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

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

Control measures

Control measures
The ubiquity of potentially life-threatening pathogens in our environment, the ability of some of them to survive or proliferate under refrigeration and in reduced oxygen atmospheres, and for some of them, the low number necessary for disease production indicate the seriousness of the potential hazards with which we are faced.

The food industry utilizes a variety of effective control measures to limit potential hazards. This is accomplished by destruction or inactivation of the relevant bacteria or their spore through the use of heat treatments, dehydration, freezing, refrigeration, specialized packaging approved anti-microbial preservatives.

Additionally, extensive quality control procedures are maintained to ensure that these processes are effective. It is for these reasons that American food supply remains the safest most wholesome in the world. However, recent consumer trends toward lower dietary salt (and thus low salt or salt free foods), towards the elimination of preservatives, and towards minimal processing significantly affect control measures and product shelf life and greatly limit the variety and type of food available.

While the food industry employs necessary control measures to ensure the safety of food until it reaches the consumer, all food handlers and consumers have the responsibility upon purchase of the food to maintain these control measures until consumption.

Any compromise of control measures, such as time or temperature abuse, alteration of product integrity, may result in growth and toxin production of pathogenic microorganisms.
Control measures