Food safety

INTOXICATION VS INFECTION Food Intoxication- toxins/ toxicants responsible Produced in foods as by-products of microorganisms, plants or animals Cause disease upon ingestion Food Infection- multiplication of pathogenic Microorganisms responsible Viable microorganisms in the food at the time of consumption-> grow in the host- cause illness.

microorganisms We can find them everywhere Microorganisms cause a great deal of food spoilage throughout the world This has major economic consequences and as well as loss of potential sources of nutrients, since the food typically is discarded.

microorganisms Examples of microorganisms: Bacteria, mold and yeast Viruses can be agents of food borne disease but VIRUSES DO NOT CAUSE FOOD SPOILAGE, NOR DO THEY PRODUCE FERMENTED FOODS

MICROORGANISMS The Good--- The BAD--- The ugly--- Used in food processing (cheese, yogurt, olives) The BAD--- Can cause food spoilage Food preservation, packaging and storage technology kills or delays metabolic activities of MO The ugly--- MO that can cause foodborne disease Food processing, packaging and storage techniques are designed to kill these MO or prevent their growth

Bacteria, yeast, molds Bacteria- unicellular organism-1 micron or less in length Gram staining- classify bacteria based on whether the bacteria retain crystal violet in their cell membrane Gram positive ( violet/blue)- thick cell wall, with no outer membrane Gram negative( pink) – thin cell wall and have an outer membrane Rods (long and narrow)

Bacteria, yeast, molds Bacteria- fast growth Generation time fir 1 cell division cycle Eg) if 7 min,then in 3.5 hrs (210 min), one cell would multiply to 2 30= 1 billion cells! Vegetative cells (active) or spores (dormant) Cocci (circular shape) and rods (long and narrow)

Bacteria Vegetative cells ( active) or spores ( dormant) Clostridium botulinum Vegetative cells ( active) or spores ( dormant) Cocci (circular shape) and rods (long and narrow)

Yeasts Yeasts- slower growth but more toleratnt Tolerant lower pH or water activity Reproduced by budding

Molds Molds- even more tolerant of low pH and water activity Grow by network of hairlike fibres (mycelia)  spores Spores mycelia

Bacteria & mold Spores Spores- dormant form Very resistent to various conditions Germinate under favorable conditions -> active vegetative cells Notorious example: clostridium botulinum Spores are very heat resistant Germinate-> Toxin-> Botulism (pathogenic) Spores do not change flavors Stomach acid will not allow spores to release BoTox- botulism toxin

Classification of microrganisms by Oxygen and Temperature requirements for growth Oxygen requirements: Faculative anaerobe- in presence / absence of oxygen Bacteria, yeasts Small amount of oxygen ( not Mold) Mold may only grow on top in jar Anaerobic- only in the absence of oxygen Bacteria only Aerobic- only in presence of oxygen Bacteria, yeast, molds

Classification of microorganisms temperature requirements min max optimum Psychrophiles 0-5 18 10 o C Psychrotrophs 0 to -5 30-35 21 cause food spoilage in frig (listeria—deli meats) Mesophiles 10 45-50 35 pathogens- cause disease/ grow in danger zone Thermophiles 50 80-100 65 spores of c.botulism Spoilage of refrigerated foods- psychrotrophs Many disease causing bacteria are mesophiles

What contributes to microbial growth?

F= Food F=Food (Carbohydrates, Proteins and Fats) A= Acidity ( pH higher than 4.6) T= Temperature ( outside danger zone 41o F to 135o F) ( keep hot foods hot, cold foods cold) T= Time (longer exposure = greater MO growth) O= oxygen (greater exposure faster MO growth) M= Moisture (water activity)

Microorganisms and Foodborne Disease Foodborne Illness Outbreaks | Food Safety News

FACTS 5200 PEOPLE DIE EVERY YEAR FROM FOODBORNE ILLNESS 76 million cases of foodborne disease occur each year in the US cdc

Foodborne disease etiology (causes) Parasitic Cryptosporidium (water) Anisakiasis (fish) Acquired from consumption of infested food/ water Plant amanita mushrooms, taro leaves, green potatoes, etc Animal Poisonous animals Shellfish containing paralytic toxins, puffer fish, etc Chemical Tin in corrosive metal cans, cleaning and sanitizing agents, etc Microbiology= food/Waterborne Diseases (FBD)

Parasitic Cryptosporidium (water) Anisakiasis (fish) Acquired from consumption of infested food/ water Parasites such as Trichinella (pork)

Plant amanita mushrooms, taro leaves, green potatoes,… FBD example- solanine from green potatoes inhibit the action of enzyme ( cholinesterase) and interfers with nerve transmissions and impulses

Potatoes cont. Low levels (potato skin= 2.13mg/ 100g fresh weight) “green” potatoes ( sunlight)-> 80-100 mg/ 100 g fresh weight Solanine is insoluble in water Lower the concentration by simply peeling potato Not destroyed by heat ( cooking) At 2-8 mg/kg baking weight humans display drowsiness, difficulty breathing, increased sensory sensitivity Toxic ( LD50= 42mg/kg) LD =lethal dose But relatively low hazard /risk unless -> green potatoes

Animal Poisonous animals Shellfish containing paralytic toxins, puffer fish, etc

Seafood toxins Saxitoxin- paralytic shellfish poisoning (psp) Neurotoxin in microscopic plankton (dinoflagellates) May bloom under certain conditions (red tide) Found in shell fish ( muscles, clams, oysters) ‘filtering’ organisms- absorb toxins from water and concentrate it in their tissues Both on east and west coasts of US Muscular and nerve paralysis Toxicity LD 5 mg/kg body wt (LD50 ) Hazzard: know source of seafood, heed red tide signs

Chemical Tin in corrosive metal cans, cleaning and sanitizing agents, etc

Reasons why only some FBD are reported? Lack of reporting- Only 1-4 % are reported Mistakenly diagnosed Mild cases blamed on 24 hour flu, a virus, overeating Doctors fail to report to local health dept due to lack of evidence/ research available 5

Who is most at risk? Very old Very young Immunocompromised Expectant mothers ( pregnant)

Mold toxins (mycotoxins)- produced by molds Ergotism-(claviceps purpurea)= st Anthony’s fire Rye and other cereal grains Chemical ergot Similar to LSD ( hallucinogens, insanity) peanuts, corn, wheat, rice, cottonseed, nuts, milk, eggs, cheese Highly toxic and potentially carcinogenic Contains vaso constricting alkaloids (precursors for LSD 25) Believed to be part of the salem witch hunt hysteria (1692) Mouldy rye bread … Science, 1976 v. 192

Mycotoxins- produced by molds Aflatoxins (aspergilus flavus) Peanuts, corn, wheat, rice, cotton seed, nuts, milk, eggs, cheese Highly toxic and potently carcinogenic liver cancer

Examples of food intoxication Clostridium botulinum E coli Food infection Salmonella Listeria Virus Hepatitus a norwalk

haccp

Factors in fbd Prep food too far in advance and store improperly Insufficient cooking/ reheating Inadequate cooling Cross contamination **most pathogenic MO do not alter color, aroma, flavor, or texture of foods

Poster project Choose one pathogen and create an illustrated poster with detailed information to present to the class. Include: Scientific name Picture or drawing of pathogen Common name Classification Food sources Symptoms/ results Possible Prevention/ elimination methods or steps Other information