FS 116 LEC

• Foodborne Illness


  • Occurs when a pathogen is ingested with food, establishes itself, and multiplies in the human host
  • Happens when a toxigenic pathogen establishes itself in a food product and produces a toxin which is ingested
• Types of Foodborne Illness


  • Infection
  • Intoxication
  • Toxicoinfection
• Factors necessary for foodborne illness to occur


  • Pathogen
  • Food vehicle
  • Susceptible host
  • Growth conditions
• Food Infection


  Caused by the ingestion of food containing live bacteria which grow and establish themselves in the human intestinal tract
• Food Intoxication


  Caused by ingesting food containing toxins formed by bacteria which resulted from the bacterial growth in the food item. The live microorganism does not have to be consumed
• Food Toxicoinfection


  Involve either sporulation or lysis of bacterial cells, and release toxin(s) from lysed cells in gastrointestinal tract
• Foodborne Pathogen


  Infectious or disease-causing agents such as viruses, parasites, fungi, prions, and bacteria for which food is the vector
• Common Food Poisoning Bacteria


  • Bacillus
  • Clostridia
  • Listeria
  • Staphylococcus
  • Salmonella
  • Escherichia coli
  • Campylobacter
  • Vibrio
• Gram-Positive Pathogenic Bacteria


  • Usually produce toxins and some produce spores
• Gram-Positive Pathogenic Bacteria


  • Bacillus (B. cereus)
  • Clostridia (C. botulinum & C. perfringens)
  • Listeria (L. monocytogenes)
  • Staphylococcus (S. aureus)
• Clostridium botulinum

  Anaerobic bacteria, soil, sediments of lakes, ponds, and decaying vegetation, organisms produce neurotoxin, bacterial intoxication, food with pH > 4.6 can support growth and toxin production, disease: botulism

  
• Clostridium perfringens


  Microaerophilic bacteria, present in environment, vegetation, sewage, and animal feces; found in human, domestic and feral animals, cold-tolerant with heat-resistant spores, causes toxin-mediated infection (enterotoxin), food sources: meat-containing products, improperly cooled and cooked foods
• Bacillus cereus

  Anaerobic, large rods, heat-resistant spores, causes two types of gastrointestinal illnesses: pre-formed heat and acid-stable toxin (emetic/vomiting syndrome), heat labile enterotoxin (Diarrheal disease), sources: milk, meat, vegetables, fish (diarrheal), rice products and other starchy foods, such as pasta and potato, cheese products (vomiting type)
• Staphylococcus aureus


  Small and spherical bacteria (commensal), produce heat-stable toxin, one of the most resistant non spore-forming human pathogen, infective dose of toxin is < 1 microgram (105 microorganism/g of food), onset: rapid (30 min. - 8 hours), symptoms: nausea, abdominal, cramping, vomiting, and diarrhea, sources of contamination: food handlers, contaminated surfaces, prevention: proper food handling, cooking food thoroughly

  
• Listeria monocytogenes

  Ubiquitous (environmental contaminant), associated with consumption of vegetables, dairy products, seafood, and RTE meats, vulnerable population/people at risk: pregnant women and newborns, senior citizens, immunocompromised (opportunistic), disease: Listeriosis, onset: GIT (gastrointestinal) symptoms > 12 hours, severe forms may range from a few days to 90 days, symptoms: pregnant women - fever and other flu-like symptoms, such as fatigue and muscle aches; miscarriage, people other than pregnant women - headache, stiff neck, confusion, loss of balance, and convulsions in addition to fever and muscle aches
• Enteric Gram-Negative Rods (Enterobacteriaceae)

  • Complex antigenic structure (lipopolysaccharides); produce variety of toxins (endotoxin) or other virulence factors, natural habitat is the intestinal tract of humans and animals (enteric)

  
• Enteric Gram-Negative Rods (Enterobacteriaceae)

  • Salmonella
  • Escherichia (E. coli O157:H7)

  
• Salmonella spp.

  Motile by flagella (except S. gallinarum and S. pullorum), non-spore forming facultative anaerobe, causes two types of illness: non-typhoidal salmonellosis (gastroenteritis) and typhoidal salmonellosis (enteric fever), two species that can cause illness in humans: Salmonella enterica and Salmonella bongori
• Salmonella enterica

  Widely distributed in nature, environmental sources: water, pond-water sediments, soil, and animal feces, spread through fecal-oral route and contact with contaminated water, survives frozen and dry state, greatest public health concern which comprise of 6 subspecies, Salmonella enterica subsp. enterica (I) - two serotypes: Salmonella Enteritidis and Salmonella Typhimurium, over 1400 serotypes

  
• Salmonella Enteritidis


  Illness: Gastroenteritis, sources: raw meat and poultry, farm irrigation, soil, insects, factory, equipment, hands, kitchen surfaces, and utensils, mostly of the concern in eggs, infective dose: as low as 100 [cells], onset: 6-72 hours, symptoms: nausea, vomiting, abdominal cramps, diarrhea, fever, headache, symptoms last 4-7 days (1-2 days for acute symptoms), Salmonella Dublin is associated with blood poisoning or infect blood, organs, and/or joints (bacteremia)
• Salmonella Typhi and Salmonella Paratyphi A


  Only found in human hosts, illness: Enteric fever, source: drinking and irrigation water contaminated by untreated sewage, prevalent in countries with poor sanitation, infective dose: ~1000 cells, onset: 7-28 days, symptoms: typhoid fever (Salmonella Typhi) and paratyphoid (Salmonella Paratyphi) fever cause similar symptoms: high fever (39-40 °C), weakness, stomach pain, headache, diarrhea or constipation, cough, and loss of appetite; rash of flat, rose-colored spots
• Shiga Toxin-Producing Escherichia coli (STEC)


  Shiga toxins (verotoxins/shiga-like toxins) are closely related or identical to the toxin produced by Shigella dysenteriae, verocytotoxin-producing E. coli (VTEC) or enterohemorrhagic E. coli (EHEC), E. coli O157:H7 is the most common identified STEC that is associated with food, symptoms: diarrhea, hemorrhagic colitis, HUS (hemolytic uremic syndrome), and TTP (thrombotic thrombocytopenic purpura), onset: 1-8 days

  
• Escherichia coli O157:H7 (STEC)

  Grows well in low-acid foods; survives at pH <4.6, infective dose: <100 cells, enterohemorrhagic, produces one or more potent toxins that cause severe damage to the intestinal lining, bacteria attach to the inside surface of the large intestine and produce shiga-like toxin in GIT, hemorrhagic colitis or bloody diarrhea, around 5-10% of those diagnosed with STEC infection develop a potential life-threatening complication, which is the HUS, symptoms of HUS: decreased frequency of urination, feeling tired at all times, losing pink color in the cheeks and lower eyelides/becoming pale, may lead to kidney failure, and sometimes death, TTP may include symptoms of: HUS, fever, neurologic symptoms (mortality in the elderly is 50%), outbreaks associated with undercooked ground beef (zero tolerance), adulterant in ground beef since 1994 (USDA FSIS), STEC serogroups O26, O45, O103, O111, O121 and O145

  
• Campylobacter jejuni

  Microaerophilic (5% O2 and 10% CO2), motile by flagella (virulence factor), susceptible to drying, heating, freezing, disinfectants, and acidic conditions, major food sources linked to infection include undercooked poultry products, unpasteurized milk, cheeses, and contaminated water, illness: Campylobacteriosis, self-limiting gastroenteritis, in which the disease does not require medication, can be cured by oral rehydration therapy (ORT) if the symptoms include mild to moderate dehydration, symptoms: mild to severe diarrhea, with loose, water stools often followed by bloody diarrhea; muscle pain, headache, and abdominal pain, bacteremia and infection of various organ systems, such as meningitis and pancreatitis (1.5/1000 cases), miscarriage and neonatal sepsis (very rare), potential long-term complication like Guillain-Barré Syndrome (1/2000 C. jejuni infections) or reactive arthritis, onset: 2-5 days (lasts to 2-10 days)

  
• Vibrio

  Vibrios are aquatic organisms, motile, aerobic, occur in fresh marine and fresh water habitats, free-living or in association with aquatic animals (mutualistic or pathogenic)
• Vibrio cholerae (serogroups O1 and O139)


  Causes cholera, produces cholerae enterotoxin (heat-labile), only pathogenic to humans, readily inactivated at temperatures >45 °C
• Vibrio parahaemolyticus

  Gastroenteritis, food source: raw/undercooked fish and shellfish, symptoms: watery (occasionally bloody) diarrhea, abdominal cramps, nausea, vomiting, fever, infective dose: > 1 million cells, onset: 4-96 hours (last 2-5 days)

  
• Vibrio vulnificus

  Gastroenteritis, food source: raw/undercooked fish and shellfish (oyster), symptoms: vomiting, diarrhea, abdominal pain, bloodborne infection. Fever, bleeding within the skin, ulcers requiring surgical removal. Can be fatal to persons with liver disease or weakened immune systems, infective dose: <105 cfu/mL, onset: 1-7 days (last 2 to 8 days)
• Foodborne Viruses


  Obligate intracellular parasites, they do not grow or make their own energy, can only replicate using a living host cell, virus consists of: DNA or RNA genome, protein coat (capsid made of capsomers), envelope: not always present (derived from the plasma membrane of the host cell), surface proteins/glycoproteins

  
• Vibrio vulnificus


  Causes gastroenteritis
• Foodborne disease from viruses


  1. They can only multiply inside the living host

  2. Are only able to get into food by external contamination (primary contamination from contaminated raw materials, secondary contamination during processing or serving)

  3. Viruses do not multiply in foods (low infective dose: ≤ 100 cells)

  4. From a food handler to food and water

  5. A potentially hazardous food (PHF) is not needed to support the survival of virus
• Hepatitis A


  Virus: Hepto Virus or Hepatitis A virus
• Hepatitis A


  • Found in human intestinal and urinary tract and contaminated water
  • Symptoms: fever, fatigue, headache, nausea, loss of appetite, stomach pain, vomiting, "jaundice"
  • Incubation time: 2-10 months after contaminated food and water is consumed
  • Infective dose: 10-100 virus particles
  • Food sources: Raw and lightly cooked oyster and clams harvested from polluted water, Raw vegetables irrigated and washed in polluted water, Food handled by a person infected with hepa A that needed no further cooking
  • Prevention: Handle foods properly, Cook at the recommended temperature, Avoid eating raw seafood, Food handlers must practice good personal hygiene, Wash hands and fingernails properly

  
• Norwalk Virus/Norovirus


  Virus: Norwalk virus/Norovirus
• Norwalk Virus/Norovirus


  • Found in human intestinal and urinary tract and contaminated food and water
  • Symptoms: nausea, vomiting, diarrhea, abdominal pain, headache, low grade fever
  • Incubation time: 12 hours – 3 days
  • Infective dose: 10-100 virus particles
  • Food sources: Ready to eat including leafy vegetables and herbs, berries and foods handled after cooking, Crustaceans, shellfish, mollusks, and their products
  • Prevention: Cook foods to a proper temperature, practice good personal hygiene, wash hands and fingernails, Primary route of transmission is person-to-person, via fecal-oral and vomit-oral routes and indirectly through foods

  
• Rotavirus


  Causes disease rotavirus gastroenteritis (self-limiting)
• Rotavirus


  • It is the leading cause of severe diarrhea among infants and children
  • Symptoms: vomiting, low-grade fever, watery diarrhea
  • Incubation time: 1-2 days
  • Transmission: person-to-person spread through contaminated hands
  • Infective dose: 10-100 virus particles
• Parasites


  Organisms living in or on another organism (host), obtaining nourishment at the host's expense
• Parasites


  • Can cause malnourishment, illness, and organ dysfunction for the host
  • Parasites cause pathogenic infections when: Large numbers of parasites are present, They interfere with organ function, Host is malnourished, ill, or immunocompromised
  • Examples: Entamoeba histolytica, Cryptosporidium parvum, Taenia saginata, Taenia solium
• Entamoeba histolytica


  Causes gastrointestinal amoebiasis