Fish 154 -Module 6. Fish and Foodborne Pathogens PDF

FISH & FOODBORNE PATHOGENS Fish 154 Lecture Module 6 MODULE TOPIC OUTLINE v Foodborne pathogens & diseases vClassification Foodborne intoxication Foodborne infection v Causative Agents of Intoxication and Infection: Biology Route of Transmission/Infection...

FISH & FOODBORNE PATHOGENS Fish 154 Lecture Module 6 MODULE TOPIC OUTLINE v Foodborne pathogens & diseases vClassification Foodborne intoxication Foodborne infection v Causative Agents of Intoxication and Infection: Biology Route of Transmission/Infection Symptoms & Diagnosis vControl/Prevention Watch info video at: https://www.youtube.com/watch?v=2QQvhFPZedM v Foodborne diseases Foodborne diseases are acute illnesses associated with the recent consumption of food The food involved is usually contaminated with a disease pathogen or toxicant.  v SuchFoodborne diseases food contains enough pathogens or toxicantdiseases ¤Foodborne necessary are acute illnesses associated to make with a person the recent sick. consumption of food Fish and foodborne pathogens are associated with economic losses v Classification of foodborne diseases 1. Intoxication 2. Infection Exotoxin causes the microorganism itself symptoms or illness grows inside the body and causes the Exotoxin - chemical or natural toxin symptoms/ illness often produced as a by-product of bacteria present in the food v Classification of foodborne diseases: 1.Foodborne intoxications These are caused by consumption of food containing: 1. Biotoxicants- which are found in tissues of certain plants and animals. 2. Metabolic products (exotoxins)- formed and excreted by microorganisms while they multiply in food, or in gastrointestinal tract of human. 3. Poisonous substances- which may be intentionally or unintentionally added to food during production, processing, transportation or storage. v Classification of foodborne diseases: 1.Foodborne intoxications ¤Food borne intoxications have short incubation periods (minutes to hours) and are characterized by lack of fever. v Classification of foodborne diseases: 1.Foodborne intoxications ¤Food borne intoxications can be classified into: a. Bacterial intoxications b. Fungal intoxications c. Chemical intoxication d. Plant toxicants, and e. Poisonous animals. v Classification of foodborne diseases: 2. Food borne infections ¤Food borne infections are caused by the entrance of pathogenic microorganisms contaminating food into the body, and the reaction of the body tissues to their presence. v Classification of foodborne diseases: 2. Foodborne infections ¤These can either be fungal, bacterial, viral or parasitic ¤Food borne infections tend to have long incubation periods and are usually characterized by fever  Module 6 – Activity A: List and tabulate the characteristics of the different foodborne pathogens tackled in this module. Causative G-/G+ Conditions for growth Types of Toxin Symptoms agent shape food produ pH temp O2 other factors ction v Foodborne Pathogens 1. Causative Agents of Intoxication ¤Staphylococcus aureus Staphyloccocal poisoning ¤Escherichia coli O157 : H7 "hamburger disease" ¤Clostridium botulinum Botulism ¤Clostridium perfringens “canteen disease” 1. Staphylococcus aureus ¤Characteristics: Facultative anaerobe with heat-stable toxin. ¤Temperature sensitivity: heat labile; toxin heat-stable. ¤Habitat: nose and throat , skin ¤Foodborne Disease: Staphyloccocal poisoning ¤Source: contaminated RTE foods ¤Cause: Poor personal hygiene and subsequent temperature abuse. ¤Symptoms: nausea, vomiting and diarrhea within 4 to 6 hours of infection. No fever. 1. Staphylococcus aureus Biology: Growth Conditions ¤Staphylococcus aureus is a facultative anaerobe, non- spore forming Gram positive cocci. ¤It grows at a range temperature between 12-44oC (optimum 37oC) and pH range 4.0-9.83 (optimum 7.4-7.6). ¤Growth occurs in an environment containing up to 18% sodium chloride and water activity of 0.86 - 0.88 when growing aerobically and 0.9 under anaerobic conditions. 1. Staphylococcus aureus Biology: Growth Conditions ¤Staphylococcus aureus is a poor competitor and therefore grows poorly or not at all when growing together with other microorganisms. ¤Majority of S. aureus food poisoning are due to foods in which the microbial flora is substantially reduced, such as cooked, cured or pasteurized foods. 1. Staphylococcus aureus Biology: Toxin Production ¤Toxin production occurs at growth temperature 12-44oC, pH 4.2 and salt concentration of ≤10%. ¤No toxin production occurs at temperatures below 12oC, pH < 4.2 and > 10 % salt. ¤All the staphylococcal enterotoxins are heat stable (withstand heating at 100oC for one hour) and ordinary cooking procedures, pasteurization and drying do not inactivate these enterotoxins. ¤They are insensitive to pH changes(pH stable) and resistant to most proteolysis enzymes (trypsin, chymotrypsin, renin, and pepsin). 1. Staphylococcus aureus Mode of Transmission ¤ Habitat: nose and throat , skin ¤Vehicle Foods: Milk and milk products (e.g. pasteurized milk, yoghurt, chocolate milk, fermented milk, cream filled pastries), poultry, fish, shellfish, meat and meat products, non- meat salads, egg and egg products, vegetables and cereal products have been involved 1. Staphylococcus aureus Symptoms & Diagnosis 1. Use of clinical symptoms -incubation time (1-6 hrs),clinical symptoms include nausea, headache, vomiting and diarrhea. 2. Enumeration of organisms in food and stool (presence of ≥106 cfu/g of S. aureus in food in indicative of involvement of the disease in an outbreak. 3. Enterotoxin detection using various methods which include: a. Serological (e.g. ELISA) b. Biological (e.g. monkey feeding tests) 4. Use of molecular biology techniques. Gene probing and polymerase chain reaction. 2. Escherichia coli O157:H7 ¤Characteristics: toxins heat stable ; heat sensitive. ¤Temperature sensitivity: organisms: heat labile; grow at freezing temperatures. ¤Habitat: Feces of infected humans ¤Foodborne Disease: “hamburger disease” ¤Source: Meat and cheeses ¤Cause: Inadequate cooking, recontamination of cooked products Symptoms: Diarrhea, abdominal cramps. No fever. 2. Escherichia coli O157:H7 Biology: Growth Conditions ¤It grows poorly at 44oC-45oC, with no growth at 45.5oC, suggesting that its presence may not be detected by fecal coliform assay test. 2. Escherichia coli O157:H7 Mode of Transmission|Cause of Intoxication ¤Improper cooking of hamburger and other meats ¤Absence of after toilet good personal hygiene ¤cross-contamination of foods in the kitchen 2. Escherichia coli O157:H7 Symptoms ¤Symptoms: Diarrhea, abdominal cramps. No fever. “Hamburger disease”: ¤Deaths occur in patients who develop hemolytic uremic syndrome (HUS). ¤HUS can be recognized by acute renal failure, micro- angiopathic hemolytic anemia and thrombocytopenia.  Escherichia coli O157:H7 Outbreak Linked to Home- Cooked Hamburger - California, July 1993 Although outbreaks of Escherichia coli O157:H7 have been linked to consumption of contaminated ground beef, the organism is rarely isolated from the implicated meat. In addition, most epidemiologic investigations of illness associated with E. coli O157:H7 infections have been directed at restaurant-associated outbreaks, and the sources of infection for sporadic cases rarely have been identified. In July 1993, three cases of culture-confirmed E. coli O157:H7 infection among persons residing in a small community in California were traced to consumption of hamburger purchased from a local grocery store; E. coli O157:H7 was isolated from that meat. http://www.cdc.gov/mmwr/preview/mmwrhtml/00026029.htm 3. Clostridium botulinum ¤Characteristics: Produces spores and requires low oxygen atmosphere. Produces ¤Temperature sensitivity: a heat-sensitive toxin ¤Habitat: Soils, plants, marine sediments, fish ¤Foodborne Disease: botulism ¤Source: Home-canned foods ¤Cause: ¤Symptoms: Blurred vision, respiratory distress and possible death 3. Clostridium botulinum Biology: Growth Conditions ¤Obligate, spore-forming anaerobe, and Gram-positive bacilli ¤The strains are divided into proteolytic and non-proteolytic types according to whether they hydrolyze proteins or not. ¤C. botulinum spores will germinate if the pH is above 4.5 and there is an absence of oxygen (i.e. anaerobic condition). ¤It is important to ensure that spoilage organisms in a high- acid food do not cause a shift in pH to the low acid level, thereby allowing the potential development of C. botulinum. 3. Clostridium botulinum Biology: Growth Conditions ¤Proteolytic strains grow at temperature range between 10-50oC, while non-proteolytic grow at 3.3-45oC (optimum 35-37oC). ¤Both strains grow at minimum pH of 4.5. ¤Proteolytic strains produce an active botulinal toxin, while non-proteolyic strains produce inactive pro-toxin that require activation by trypsin. 3. Clostridium botulinum Biology: Toxin Production ¤Toxin production occurs at temperature range between 25-30oC. ¤These toxins are neurotoxins, that are highly toxic, heat labile (inactivated by heating at 80oc for 10 min), unstable at alkaline pH (but stable below pH 7.0) but resistant to pepsin and acidic environment. ¤The toxins can resist the action of the gastric and intestinal juices. ¤Botulinum toxin is one of the most lethal poisons known. The calculated lethal dose for an adult person is 10 µg. 3. Clostridium botulinum Cause of Intoxication 1. Contamination of food due to improper handling. 2. Insufficient heating of food to destroy spores. 3. Spores present in animal tissues (e.g. meat, fish). 3. Clostridium botulinum Preventive Measure ¤Ensuring proper manufacturing practices e.g. ensure proper sterilization and preservation of canned meat ¤Preserved foods possessing rancid or other odors should be rejected ¤Proper heating of food before consumption to destroy heat labile neurotoxins. Food should be heated to 80oC and temperature maintained for at least 10 min before eating. ¤Picked foods are rendered safe if the brine used contain not less than 10 % common salt, in weaker brines, microorganisms can continue to multiply. 3. Clostridium botulinum Preventive Measure ¤Ensuring fast cooling of food. This will ensure that spores that may be remaining do not germinate in food. ¤Utmost care should be taken in the manufacture of cans, their transport, handling, storage and subsequent use during packaging of product. 4. Clostridium perfringens ¤Characteristics: Produces spores and prefers low oxygen atmosphere. ¤Temperature sensitivity: ¤Habitat: Dust, soil and gastrointestinal tracts of animals and man. ¤Foodborne Disease: “canteen disease” ¤Source: Meat and poultry dishes, sauces and gravies. ¤Cause: improper temp control of hot food ¤Symptoms: Cramps and diarrhea within 12 to 24 hours. No vomiting or fever. 4. Clostridium perfringens Biology: Toxin Production ¤Spores produced by these organisms can resist boiling for 4 or more hours. ¤If the spores are present as contaminants on raw meat, they may resist boiling or steaming, and on slow cooling the spores will germinate into rapidly multiplying bacterial cells, which produce large amounts of toxin. 4. Clostridium perfringens Biology: Toxin Characteristics ¤Clostridium perfringens enterotoxin (CPE) is synthesized during sporulation. ¤CPE is heat labile (destroyed at 60oC for 10 min) and its activity is enhanced by trypsin. ¤The food poisoning strains are heat resistant and survive heating at 100oC for 1 hr). 4. Clostridium perfringens Cause of Intoxication ¤Clostridium food borne intoxication is caused by the ingestion of food containing large numbers of vegetative cells of enterotoxigenic C. perfringens type A and some type C and D strains. ¤These cells multiply in the intestine and sporulate releasing Clostridium perfringens enterotoxin (CPE). 4. Clostridium perfringens Cause of Intoxication ¤Sometimes CPE may be pre-formed in food, and once the food is consumed, symptoms may occur within 1-2 hours. ¤Improper temperature control of hot foods and recontamination can cause the disease. ¤Temperature sensitivity: Normal cooking kills bacteria but heat-stable spores can survive. 4. Clostridium perfringens Cause of Intoxication ¤Cooking kills the vegetative cells of Cl. perfringens but activates surviving spores, which will germinate and multiply. ¤Foods poisoning occurs when the level reaches 107-108 cells/g of food ¤Growth is enhanced by anaerobic conditions achieved after removal of oxygen by cooking., 4. Clostridium perfringens Cause of Intoxication: Vehicle Foods ¤The food involved are those that are prepared one day and served the next day. ¤Foods that have been involved include red meats, chickens, fish, pork, fruits, vegetables, spices etc. ¤The heating of such foods is inadequate to destroy heat resistant endospores, ¤Upon cooling and warming the endospores germinate and grow. 4. Clostridium perfringens Mode of Transmission 1. Directly from slaughter animals 2. Contamination of slaughter meat from containers, handlers, dust, and water. 3. Cross -contamination in the kitchen environment. 4. Clostridium perfringens Preventive Measure 1. Proper cooking of food and eating freshly prepared foods. 2. Thorough washing and sanitation of containers 3. Hygiene handling of cooked food 4. Fast cooling of cooked food. Storing food in small quantities will enhance cooling. 5. Proper reheating of cold cooked food before consumption 6. Storage of leftovers or unused foods in freezers v Foodborne Pathogens 2. Causative Agents of Infection ¤Salmonella ¤Campylobacter jejuni ¤Listeria monocytogenes ¤Shigella ¤Vibrio parahaemolyticus 1. Salmonella ¤Characteristics: Produces an intestinal infection. ¤Temperature sensitivity: No growth below 40°F. Can be destroyed by normal cooking. ¤Habitat: Intestinal tracts of animals &human beings. ¤Source: High protein foods(meat, poultry, fish, eggs) ¤Cause: Contamination of ready-to-eat foods, insufficient cooking & cooked foods contamination ¤Symptoms: Diarrhea, nausea, chills, vomiting and fever within 12 to 24 hours of infection. Watch the animated info video at: https://www.youtube.com/watch?v=xOamez79hLA 1. Salmonella Biology ¤Gram negative, motile with petritrichous flagella non- sporeforming rods, facultatively anaerobic and mesophilic. ¤The salmonellae constitute a group of organisms with over 2000 different serotypes. ¤Many salmonella species have a wide host range. These are the organisms which commonly cause food poisoning. 1. Salmonella Biology: Common food poisoning serotypes ¤Some of the salmonella species involved in food poisoning include; Salmonella typhimurium, Salmonella enteritidis, Salmonella dublin, Salmonella softenburg, Salmonella virchow, Salmonella montevideo, Salmonella infantis, and salmonella newport. ¤These species are also involved in causing diarrhea in animals 1. Salmonella Cause of Infection & Vehicle Foods ¤A heavy dose up to 10,000 -1,000,000 organisms per gram of food is required to cause infection ¤Aquatic environment are the major reservoirs for Salmonella, thus fishery products have been recognized as major carrier. ¤Fresh fish, fish meal, farmed aquatic products can carry Salmonella if they are caught in areas with fecal contamination. 1. Salmonella Biology: Heat Resistance ¤The salmonellae are killed by temperatures attained in commercial pasteurization, ¤They can remain alive in moist earth for one year and in dry earth for 16 months, ¤They are not destroyed in carcasses or offal maintained at chilling or freezing temperatures, or in the usual pickling solutions 1. Salmonella Factors associated with Salmonella food poisoning outbreaks ¤Consumption of inadequately cooked or thawed meat or poultry, ¤Cross-contamination of food from infected food handlers. ¤Presence of flies, cockroaches, rats, in the food environment that act as vectors of the disease. 1. Salmonella Mode of Transmission ¤Salmonellae reach food in many different ways; 1. Directly from slaughter animals to food 2. From human excreta, and transferred to food through hands, utensils, equipments, flies etc. ¤Food poisoning is more likely to occur if the total number of microorganisms present is high. A smaller number may have no ill effect. 1. Salmonella Preventive | Control Measures ¤Efficient refrigeration and hygienic handling of food. ¤Consumption of properly cooked meat, ¤Complete thawing of frozen meats and adequate cooking. ¤Heat processing of meat, milk , fish and poultry to destroy salmonella organisms in food 2. Campylobacter jejuni ¤Characteristics: Oxygen sensitive, does not grow below 86°F. ¤Temperature sensitivity: Sensitive to drying or freezing. Survives in milk and water at 39°F for several weeks. ¤Habitat: Animal reservoirs and foods of animal origin. ¤Source: Meat, poultry, milk, and mushrooms. ¤Symptoms: Diarrhea, abdominal cramps and nausea. ¤Cause: Improper pasteurization or cooking, cross- contamination. 2. Campylobacter jejuni Biology ¤Campylobacter are a group of tiny strictly micro-aerophilic curved or spiral Gram negative rods ¤Campylobacter jejuni and Campylobacter coli cause food poisoning and are associated with acute enterocolitis in human. 2. Campylobacter jejuni Biology ¤Campylobacter jejuni occur in large numbers in cattle feces, and poultry as normal flora. ¤Campylobacter coli are commonly associated with human diarrhea, and enteritis in pigs mostly in association with Treponema hyodysenteriae. 2. Campylobacter jejuni Mode of Infection ¤Infection occurs by ingestion of campylobacter organisms in contaminated foodstuffs. ¤Foods involved includes meat from infected animals, unpasteurized milk and possibly cross-contamination from these sources to foods eaten uncooked or unrefrigerated. ¤The infectious dose is thought to be small, typically