Microbiology ICA-2

- BORNE.

Virus Bacteria Biological agentsthatcauses Parasitesfoodborneillnessevent.

Foodborne Illness Occurs When pathogen ingested with food Starts to multiply in host OR Produces toxins in food product ( before ingestion ) toxins causes the illness inside the host ( after ingestion ).

Food Borne Illness Food Borne Infection Food Borne Intoxication Food already has toxins from germs Food has living germs they need time to grow & multiply Symptoms appear quickly Symptoms take longer time to appear Time Minute to few hours Time Hours to days.

[Audio] Food Borne Bacteria Bacteria — most common cause of foodborne diseases Some pathogenic bacteria can form Spores Highly heat resistant 1. Clostridium botulinum 2. Clostridium perfringens 3. Bacillus subtilis 4. Bacillus cereus.

[Audio] Heat resistant toxins Some bacteria produce Cooking may kill bacteria but Toxins remain Example Staphylococcus aureus Clostridium botulinum Most foodborne pathogens are mesophilic Grow @ 20 – 45 °c.

[Audio] Psychrotrophs Grow at refrigeration temperatures (<10 °C) Refrigeration does not completely stop their growth Common psychrotrophic foodborne pathogens : Listeria monocytogenes Yersinia enterocolitica.

[Audio] Bacillus cereus Bacillaceae family Gram positive Motile rod bacterium Ability to form spores 1. Highly resistant 2. Appendages/pili aids attachment 3. Highly hydrophobic 4. Adhere strongly to many surface 5. Resistance to cleaning and sanitation Widely present — soil,fresh water, and marine environments.

[Audio] Clostridium botulinum Spore forming bacteria family Bacillaceae Gram positive motile rods Obligate anaerobes (grow without oxygen) Endospore Do not form spores in presence of air Formed under unfavorable conditions Located terminally Produce botulinum neurotoxins Make cells appear swollen/distended Highly resistant — survive: Long boiling Exposure to air.

[Audio] Botulinum Neurotoxin Cell lysis occurs Bacterial growth Neurotoxin synthesized inside cell Toxin enters bloodstream Toxin released Proteolytic cleavage activates toxin Reaches neuromuscular junction Irreversibly binds to nerve endings Internalized into nerve cell Leads to botulism symptoms.

[Audio] Escherichia coli Gram negative, Rod shaped bacterium Non spore forming May be motile (some have flagella, some do not) Facultative anaerobe (can grow with or without oxygen) Ferments simple sugars like glucose Produces: Lactic acid, Acetic acid and Formic acid Large and diverse group of bacteria Most strains harmless Some strains pathogenic (disease causing) produce toxins Spread through contaminated food and water Can survive long periods in the environment Can grow in vegetables and other foods.

[Audio] Food Borne Virus Very small, particulate agents Multiply only inside living cells Cannot survive long outside a host Over 100 types of enteric viruses — foodborne illness Common Foodborne Viruses Hepatitis A virus Norovirus High Risk Foods Bivalve molluscs: Clams Mussels Oysters.

[Audio] Hepatitis A Environmentally Stable Virus Single positive stranded R-N-A Picornavirus family Only species genus Hepatovirus Hydrophobic in nature Non enveloped virus (no lipid envelope) Very stable under harsh conditions: Freezing HeaT Chemicals Drying (desiccation) Transmitted through: Contaminated food Contaminated water Contaminated surfaces (tables, utensils) Person to person contact.

[Audio] Norovirus Cause of acute viral gastroenteritis Non enveloped virus Single stranded R-N-A genome Highly infectious R-N-A virus Common outbreak in: Nursing homes Hospitals Military camps Cruise ships.

[Audio] food borne parasites Common foodborne parasites :1. Cyclospora cayetanensis 2. Toxoplasma gondii 3. Trichinella spiralis. One celled microorganisms No rigid cell wall Have organized nucleus Larger than bacteria Do not multiply in food — only in host Infective stage called cyst Spread through contaminated: Food Water Feces.

[Audio] Cyclospora cayetanensis Toxoplasma gondii Trichinella spiralis Protozoan parasite Protozoan parasite Phylum Apicomplexa Family Eimeriidae Parasitic roundworm Infects small intestine Phylum Nematoda Obligate intracellular pathogen Causes Toxoplasmosis in humans Causes Trichinosis in humans Affects Immunocompromised& Immunocompetent individuals Infects humans and other mammals Transmitted by Eating undercooked meat , blood transfusion et cetera, Symptoms : Fever,Rash,Headache, Muscle pain, Swollen lymph nodes Symptoms : Non bloody diarrhea,Nausea, anorexia, Bloating, Abdominal cramps, Fever, Fatigue Symptoms : Eosinophilia, circumorbital edema, myalgia, Nausea , fever etc ,..

[Audio] BY : Ashika A Msc Zoology. BY : ASHIKA.A MSc ZOOLOGY.