food borne infection.clostridium .pptx

Foodborne infection- ingestion of viable pathogens along with food e.g. typhoid 
Foodborne intoxication (poisoning)- ingestion of foods containing preformed toxins e.g. botulism, staphylococcal poisoning 

1. By Apoorva Udayashankar Department of Life sciences Kristu Jayanti Autonomous College

2. Contents Foodborne infections and intoxications Clostridium Salmonella Shigella Staphylococcus Campylobacter Listeria Mycotoxins in food with reference to Aspergillus species

3. INTRODUCTION Foodborne diseases may be caused by bacteria and bacterial toxins, viruses, fungi and fungal toxins, zoonotic parasites/protozoans, pesticide residues, drug residues, heavy metals, food adulterants and food additives. Food poisoning can be of three types: Foodborne infection-  ingestion of viable pathogens along with food e.g. typhoid  Foodborne intoxication (poisoning )- ingestion of foods containing preformed toxins e.g. botulism, staphylococcal poisoning  Toxico-infection - organisms produce toxins  in situ  when ingested along with food e.g.  B. cereus  poisoning

4. Figure: Classification of foodborne diseases

5. Figure examples of bacteria responsible for foodborne intoxications and infections

6. Foodborne infections Mycotic foodborne infections include  Candida  spp.,  Sporothrix  spp.,  Wangiella  spp. etc),   Viral foodborne infections include hepatitis A & E, Norwalk virus and poliomyelitis virus  Parasitic foodborne infections include hydatidosis, Taeniasis, Anisakiasis, Trichinosis  Protozoal foodborne infections include Cryptosporidiosis, toxoplasmosis, Sarcocystosis and cyclosporiasis

7. Clostridium Two species of clostridium are of significant importance in the food industry, namely the Clostridium perfringens and Clostridium botulinum. Clostridium perfringens Gram-positive rod-shaped bacterium capable of forming end, the dormant spores can change to potentially harmful vegetative cells if exposed to cooking temperatures and when allowed to stand at temperatures between 41 to 120 °F The vegetative cells are killed when the foods are cooked at or above 140 °F, however, the spores can survive the process of cooking It is an anaerobic organism and hence can thrive in very little or no oxygen conditions. It doesn’t grow at refrigeration or room temperatures. Found in soil, water, sediments, the intestine of domestic animals and humans, sewage, and areas prone to sewage contamination They cause food poisoning when People consume large number of the bacteria, which then multiply and produce toxins in the intestine When people eat contaminated food with toxin already in it.

8. SOURCE: Common sources of C. perfringens infection include root vegetables, canned foods, meat, poultry, gravies, and other foods cooked in large batches and held at an unsafe temperature. Outbreaks tend to happen in places that serve large groups of people, such as hospitals, school cafeterias, prisons, and nursing homes, and at events with catered food. Disease: t he symptoms are caused by a toxin that is produced by the bacteria. When large numbers of vegetative  C. perfringens  bacteria are ingested, bacteria that survive the acid conditions in the gut, grow in the intestines, form into spores and release an enterotoxin that results in diarrhea. When  C. perfringens  is introduced into deep wounds, the toxin produced results in damage to the skin and deeper tissues. Symptoms: Most people with  C. perfringens  infection develop diarrhea and stomach cramps within 6 to 24 hours after eating contaminated food. The illness usually begins suddenly and lasts for less than 24 hours. Diarrhea can cause dehydration, so it’s important to drink plenty of fluids. This infection usually does not cause fever or vomiting, and it cannot be passed from one person to another. Diagnosis: Stool samples are analyzed for the presence of pathogen/ enterotoxin Prevention: Cooking in the right temperatures, promptly refrigerate leftover cooked meat and reheat it thoroughly (internal temperature, 75° C) before serving, proper storage of canned foods. Treatment: Food poisoning from  C. perfringens  is mainly supportive as it will resolve on its own.

9. Clostridium botulinum Of the many types of foodborne illnesses,  botulism  is one of the most dangerous. It can cause  paralysis  and it can be life-threatening, but it is rather rare. Botulism is caused by the bacterium  Clostridium botulinum , It releases a neurotoxin, which is a poison that attacks your  nervous system . Clostridium botulinum  is an anaerobic, rod-shaped spore-forming bacterium that produces a protein with characteristic neurotoxicity. Under certain conditions, these organisms may grow in foods producing toxin(s). Botulism, a severe form of food poisoning results when toxin-containing foods are ingested. The organism is resistant to heat, radiation, drying and the spores can survive several hours of boiling while toxins are heat sensitive. Seven types are distinguished on the basis of the serological specificities of their toxins: Type A: is the one commonly found in human botulism and is more toxic than B Type B: is found often than type A in moist soils and is less toxic to humans Type C: causes botulism of fowls, cattle, and other animals but is not reported in humans Type D: Is associated with forage spoiling of cattle Type E: Toxic to humans and has been reported from fish and sea products Type F: produces human botulism Type G: has been isolated from soil but not reported botulism in human

10. C. botulinum is widely distributed in soils and in sediments of oceans and lakes. The finding of type E in aquatic environments by many investigators correlates with cases of type E botulism that were traced to contaminated fish or other seafood. Types A and B are most commonly encountered in foods associated with soil contamination. Symptoms : Double or blurred vision, Drooping eyelids, Difficulty swallowing, Slurred speech, Shortness of breath, weakness. Diagnosis: Stool samples are analyzed for the presence of pathogen/ toxin Prevention : The botulism toxin can be killed at high temperatures, so if you’re eating home-canned food, consider boiling it for 10 minutes to kill the bacteria. Proper refrigeration can help prevent the growth of  C. botulinum , too . Treatment : Antibiotics, Antitoxins Contamination in canned foods: The can has a bulge. The container spurts out foam or liquid when you open it. The contents smell unusual or foul.

11. Reference William C Frazier and Dennis C West Hoff (1995),  Food microbiology , fourth edition, Tata Mcgraw Hill.   Aneja K.R.( 2018), Modern Food Microbiology, Medtech.