toxicants in food and food borne disease (lesson 12: fnh200)

Safe food handling practices - Preparing, Serving, cooking, Storage

*CLEAN* -hands, utensils, cooking surfaces- soap and hot water -Sanitize with a mild bleach solution ( or approved sanitizer) *SEPARATE* - Avoid cross-contamination: - separate raw & cooked food *COOK* - Prepare foods quickly and cook them thoroughly & serve immediately *CHILL*- Refrigerate or freeze leftovers within two hours - Refrigerator is set at < 4°C , freezer set at -18°C Avoid *"temperature danger zone"* (TDZ) =between *4°and 60°C*

naturally occurring toxicants

*Constituents* - form part of the food.... *Contaminants*- become part of the food --> foodborne and waterborne diseases --> not responsible by humans

Processing Induced Toxicant

- Acrylamide - Benzene - ACBs

tetrodotoxin

- fugu poisoning Isolated from puffer fish - Produced by a bacteria associated with the ovaries, liver, intestine, skin of this fish - Meat from fish is considered a delicacy

risks with saxitoxin

- paralytic shellfish poisoning (PSP) - Muscular and nerve paralysis - Toxicity: lethal dose: 1-4 mg/kg body weight - hazard - depends on your passion for shellfish, and its source (where/when harvested) - Ignoring "red tide" warning signs!

saxitoxin

- paralytic shellfish poisoning (PSP) - shellfish (eg mussels, clams, oysters) --> 'filtering' organisms- absorb toxin & concentrate it in their tissues -Toxin produced by dinoflagellates -->Found in plankton responsible for red tides

facts about toxicants and foodborne ilnesses

-5200 People Die Every Year From Foodborne illness. -->Centers for Disease Control (US) -11-13 million Canadians suffer every year from illnesses caused by foodborne bacteria. -->Health Canada -foodborne illnesses can result in chronic health problems in 2 to 3 per cent of cases -->Health Canada

toxicity

-Ability of a chemical to damage a biological system -->Substances vary in toxicity --> Diff. sensitivity among individuals -Measured by LD50 (mg/kg b.w. or ppm)- lethal dose for 50% of the population --> measures short-term poisoning (acute toxicity) --> The lower the LD50 the stronger the toxicity --> Any substance with LD50 of 50 ppm/kg or lower is considered poison

environmental toxicants

-Food packaging residues -Pesticide residues -Heavy metals -Animal Drugs -

toxicant

-From Latin "toxicum " (poison) -produce a whole spectrum of effects (minor .... --> death)

What is meat glue? Is it allowed in Canada? What are your thoughts on its use?

-Meat glue: sticks together pieces of meats, in order to sell as a prime cut of meat. It is made of transglutaminase, which comes blood plasma from pigs and cows, using it's coagulating properties. Experts can't tell the difference. -Its allowed in Canada under certain conditions. -Risks for microorganisms and foodborne disease since outer pieces containing MO are mixed with the internal parts. It is sold as one cut of meat, so people not knowing may not throughly cook the steak and since pieces are stuck together, MO will not be completely destroyed.

risks of green potatoes

-Not destroyed by heat (cooking) - At 2-8 mg/kg b.w. humans display drowsiness, difficult breathing, increased sensory sensitivity - Toxic (LD50= 42 mg/kg) - but relatively low hazard/Risk (unless green potatoes)

hazard

-Probability that injury will result from use of a chemical at a given exposure - Assessing a hazard by: 1) inherent capacity to cause harm (toxicity) 2) probability of contact btwn. substance & target object.

HACCP

-The Hazard Analysis and Critical Control Points (HACCP) system is designed to anticipate and control problems before they happen. -Processing flow diagram -> Identifying Critical Control Points

Who's most at risk for foodborne ilnesses?

-The very old -The very young -Those with weakened immune systems -Expectant (pregnant) mothers

domoic acid

-amnesic shellfish poisoning - First discovered in Canada (PEI) in 1987 --> 107 cases acute poisoning from blue mussels - produced by plankton -Toxicity (some deaths; others with long-lasting effects) -->*Permanent memory loss* --> neurotoxin - cause lesions in the central nervous system - hazard - depends on consumption of shellfish --> ignoring signs indicating closure of areas to shellfish harvesting

Pesticide residues

-herbicides, insecticides, fungicides - E.g. malathion residues on fruit

Cholinesterase inhibitors- Solanine

-inhibit action of enzyme (cholinesterase) --> nerve transmission/impulses - neurological and GI disorders -in potatoes -->low levels in the skin2-13 mg/100 g fresh weight) --> "green" potatoes (sunlight) 80-100 mg/100 g f.w. - solanine - insoluble in water -minimize hazard: dec concentration by peeling/ cutting off green, or don't eat if a child

histamine

-produced in high levels by bacterial action on fish flesh -Histidine: naturally occurring amino acid -high in scombroid fish (tuna, bonito, mackerel and skipjack) -Bacteria convert histidine --> histamine "Scombroid poisoning" from eating scombroid fish causes: - Nausea, vomiting, facial flushing, thirst, skin itchiness - Effects subside ~ 12 hrs

Top 4 places where food can be mishandled and lead to foodborne disease incidents:

1. Food Service Establishments 2. Food Processing Establishments 3. Retail Food Establishments 4. Homes

steps of HACCP

1. Identify hazard - FATTOM (food, acidity, time, temp, oxygen, moisture) 2. Determine CCP (critical control point) 3. Institute Control Measures 4. Monitor CCP 5. Take Corrective Action 6. Keep records 7. Verify Procedures

Types of toxicants based on occurrence or origin

1. Naturally occurring toxicants - constituents - Part of the normal composition of food 2. Naturally occurring toxicants - contaminants - Not originally part of the food - due to bacterial or mould growth - Plant or animal grown in an environment which permitted the Nat. Tox. to become part of the food 3. Environmental toxicants - Not originally part of the food; - introduced in environment as a result of human actions

temperature danger zone

4º-60ºC

what LD values are toxic

50 or less is toxic -smaller number is more toxic

Animal Drugs

Antibiotics, hormones E.g. penicillin in milk

Naturally occurring constituents as toxicants

Cholinesterase inhibitors- Solanine Cyanogenic (or cyanogenetic) glycosides

Selected causes of microbial food-poisoning - Viruses

Do not multiply in the food • Usually oral-fecal route of contamination; infect upon ingestion - e.g. shellfish from contaminated water Examples: • Hepatitis A • Norovirus: formerly known as Norwalk-like viruses Prevention: -Inactivated by *thermal processing* and *hygiene* (sanitary food handling)

risks of Cyanogenic (or cyanogenetic) glycosides

Fatal in humans at 0.5 - 3.5 mg/kg --> e.g. 100 g of bitter almonds or dried bitter cassava root - Toxic (LD50= 0.81 mg/kg) - Low hazard from accidental consumption of fruit seeds; ↑ hazard if cassava, lima beans etc. part of staple diet - Non-fatal at lower doses

food intoxication vs food infection

Food intoxication - *toxins /toxicants* responsible --> produced in foods as by-products of MOs, plants or animals - cause disease upon ingestion Food infection - *multiplication* of pathogenic MOs responsible -->*viable* MOs in the food at the time of consumption --> grow in the host- cause illness

Listeria

Foods: - refrigerated smoked fish, raw or unpasteurized milk, soft and unpasteurized cheeses, ready-to-eat meats Symptoms: -Fever, nausea, cramps, diarrhea, vomiting,.... -Symptoms of severe listeriosis may appear up to 70 days after you have been exposed to Listeria. It is reported to cause miscarriage and stillbirth Prevention: -killed by *heat* (cooking, pasteur.) & *irradiation*; *hygiene* (sanitary food handling)

norovirus

Foods: Raw shellfish, any food prepared or touched by an infected person. Easily spread from infected person up to at least 3 day after they recover symptoms: -Diarrhea, vomiting (children usually experience more vomiting than adults), nausea, stomach cramps -Other symptoms :low-grade fever, headache, chills, muscle aches, fatigue (a general sense of tiredness) -symptoms of gastroenteritis within 24 to 48 hours, but symptoms can start as early as 12 hours after exposure. The illness often begins suddenly Prevention: killed by heat (cooking, pasteur.) hygiene (sanitary food handling)

clostridium botulinum

Foods: low acid foods (pH > 4.6) & anaerobic conditions, potatoes, carrots Symptoms: double vision, dry mouth, paralysis - actively growing cells --> botulism neurotoxin - LD50 for humans 1 ng/kg b.w. (small amount=lethal) Prevention: - vegetative cells easily killed by heat - Spores- *heat resistant* --> "botulinum cook" (Lesson 6: 12D to destroy 1012 spores) -Keep pasteur. Carrot juice refrigerated (< 4ºC)

Salmonella

Foods: raw or undercooked poultry, eggs, hogs, ground beef, milk & dairy products symptoms: -cramps, chills, vomiting, diarrhea, fever -symptoms usually start within 6 to 72 hours after exposure. -Most symptoms end within 4 to 7 days. Prevention: -killed by *heat* (cooking, pasteur.) & *irradiation*; *hygiene* (sanitary food handling)

Escherichia coli 0157:H7

Foods: undercooked ground beef; unpasteur. milk & fruit juice, alfalfa sprouts, spinach, drinking water - *acid-tolerant*: often survive in acidic foods (eg. apple juice) Symptoms: - bloody diarrhea --> kidney failure; hemolytic uremic syndrome esp in children Prevention: easily inactivated by heat (pasteur.); irradiation - cook food especially ground beef well; - does not grow well at temperatures < 8-10ºC - Hygiene (sanitary food handling)

What are the main causes of foodborne illnesses in the order of importance

From general public perspective - Food Additives From Regulatory Agency perspective - Microorganisms

Naturally occurring contaminants as toxicants - Seafood toxins

Histamine Saxitoxin domoic acid terodotoxin

Myths and facts about chemicals and food safety -Unprocessed and organically grown food are completely free of harmful chemicals I -t is possible to demand a food supply that is completely safe

Myth: Unprocessed and organically grown food are free of harmful chemicals Myth: It is possible to demand a food supply that is completely safe (zero risk of harm) Fact: All foods consist of "chemicals" Fact: All substances (chemicals) are toxic at some level and potentially harmful Fact: Zero risk is unattainable in food safety (and in life!)

dose-response curve

No effect level ÷ 100 = ADI "Every substance is toxic at some dose, but not every substance is hazardous at commonly used doses." -as dose increases, response/effect increases, but theres a maximin response/effect

known etiology (causes)

Parasitic - Parasites such as Cryptosporidium (water); Anisakiasis (fish) - Acquired from consumption of infested water/foods Plant -Amanita mushrooms, taro leaves, green potatoes, etc. Animal - Poisonous animals (eg. Shellfish containing paralytic toxins, puffer fish, etc.) Chemical - cleaning & sanitizing agents, etc Microbiological = Food/Waterborne Diseases (FBD)

Examples of Food infection

Salmonella Listeria

incident

Simple occurrence of foodborne illness

red tide/ bloom

Source of the saxitoxin - contained in microscopic plankton (dinoflagellates) which may "bloom" under certain conditions (red tide)

Examples of Food intoxication:

Staphylococcus aureus Foods: contaminated and undercooked food exposed to open wounds and nasal fluid. Produce heat resistant enterotoxin. Symptoms: rapid onset of nausea, vomiting, abdominal pain, cramps, and diarrhea. - 20 ng toxin can cause the illness • Prevention: easily inactivated by heat (pasteur.) - cook food well; - does not grow well at temperatures < 4ºC (refrigerated temps) - Hygiene (sanitary food handling)

example of food intoxication

clostridium botulinum Escherichia coli 0157:H7

Why are hamburgers a concern, but not beef steak that is consumed "blue or rare"?

cut of beef/steak: only surface can be contaminated with MO, so inside flesh has no MO, so when grilled, MO are killed ground beef: mix of internal, surface, so MO can be anywhere

Cyanogenic (or cyanogenetic) glycosides

eg. *amygdalin* in bitter almonds (not toxic) and fruit pits; *linamarin* cassava, lima beans, - Compounds that yield HCN (hydrogen cyanide) - are toxic --> Upon enzymatic action (beta-glucosidase), acidic conditions --> high levels in some foodstuffs

boric acid (borax)

example of a hazard LD50 = 1240 mg/kg - mild acid used as an antiseptic, insecticide, flame retardant - In some cultures added to foods! (banned in Canada) --> firming agent, preservative, or tenderizer! - Not highly toxic -->Very hazardous when used in a manner that makes it easily available for accidental ingestion.

strychnine

example of a hazard (plant from SE Asia) LD50 = 1.2 mg/kg - Extremely toxic chemical --> only a small amount is needed - severe effect in people - when sealed in an un-openable vial, can be handled freely by people with no chance that poisoning will occur - Its toxicity has not changed - No hazard: no contact can be established btwn the chemical & people.

Radioisotopes

from soil or from radioactive fallout

environmentally occurring toxicants

human activities are responsible for them being in our food supply

Discuss when and why mechanical tenderization might pose a hazard

if blades are continuously piercing the surface, surface MO now may be inside the flesh, so it must be thoroughly cooked

black licorice

if over consumed, the compound causes blood pressure to rise

Heavy metals

lead, mercury, cadmium

Food packaging residues

monomers of plastic resins

alphatoxins

mycotoxin (Aspergillus flavus) - peanuts, corn, wheat, rice, cottonseed, nuts, milk, eggs, cheese - Highly toxic and potently carcinogenic --> Liver cancer

Ergotism alkaloid (Claviceps purpurea)

mycotoxin -grain of rye grass infected with ergot (Claviceps purpurea) - contains vaso-constricting alkaloids --> precursors for LSD 25 - Salem witch hunt "hysteria" (1692) --> mouldy rye bread...(Science, 1976 v.192)

Naturally occurring contaminants as toxicants

mycotoxins bacterial toxins seafood toxins

Mycotoxins

produced by moulds - *Ergotism alkaloid* (Claviceps purpurea)= St. Anthony's Fire - *Aflatoxins* (Aspergillus flavus)

symptoms of tetrodotoxin

symptoms: - tingling sensations (fingers, toes, lips, tongue) minutes after eating - Reflexes of pupil & cornea are lost - Paralysis, respiratory distress, death Toxicity- LD 1.0 - 4.0 mg/kg b.w. - hazard - depends on passion for these "delicacies", and proper cleaning and gutting of the fish.

bacterial toxins

toxins produced by Clostridium botulinum and Staphylococcus aureus... -foodborne illnesses

outbreak

• 2 or more people after ingestion of the same food • Epidemiological evidence

Why are Foodborne Diseases "Emerging"?

• Globalization of food supply - Pathogens introduced to new areas • Travel • Change in lifestyle --> a century ago, most food was local, total it comes from all over the world

Factors in Foodborne Disease

• Inadequate cooling of foods • Preparation of food several hours in advance • Poor personal hygiene and Crosscontamination • Insufficient cooking or reheating of food • Improper hot storage Most pathogenic MOs do not alter the colour, aroma, flavour or texture of food!!

Reasons why only some foodborne disease outbreaks are documented:

• Lack of reporting- only *1-4% are reported*! • Mistakenly diagnosis - Mild cases of FBD wrongly attributed to "24 -hour flu" , "virus" , "eating too much" - not documented • Physician fail to report the case to local health units - Not enough evidence/research available

outbreak of unknown etiology

• No Epidemiological evidence (what the reason for illness what)