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Group Members o Muhammad Shahid o Ayesha Butt o Laraib Shoaib o Fatin Atique o Fatima Sayed Topic • Margins of Safety • Factors Affecting Toxicity • Dose Response Relationship • Manifestation of Organ Toxicity Stay Attentive ! Activity is following this presentation “All substances are poisonous, there is none which is not a poison; the right dose differentiates a poison from a remedy.” Paracelsus Circa 1538 Chemical Poisons, Biological Toxins Poison –A chemical substance that can cause illness or death when it enters our bodies. Toxin –A poison of biological origin, specifically a protein molecule produced by a plant or animal. The terms are often used interchangeably. Toxicity Some depends on dose. substances are beneficial at low concentration but are toxic at high conc. Types of Foodborne Illness Infection – eating food contaminated with pathogens Intoxication – eating food contaminated with the toxins (poisons) formed by bacteria – eating food contaminated with other biological or chemical toxins (poisons) Toxin-mediated infection – eating food contaminated with pathogens that grow in the body and form toxins (poisons) Foodborne Diseases Infections Intoxications Chemical Poisoning Poisonous Plant Tissues Poisonous Animal Tissues Toxicoinfection Microbial Intoxications Other Neurotoxins Invasive Infection Enterotoxins Intestinal Mucosa Mycotoxins (Fungal Toxins) Algal Toxins Bacterial Toxins Diarrhogenic Emetic Enterotoxins Neurotoxins Other Systemic Other Tissues or Organs (Muscle, Liver, Joints, Fetus, Other) Controlling Bacteria Good personal hygiene Only allow healthy workers to handle food. Have all workers wash their hands properly and frequently. Prevent cross-contamination Store foods properly. Only use cleaned and sanitized utensils and surfaces for food preparation. Time-temperature control Cook foods to proper temperatures. Hold foods at proper temperatures. Common Foodborne Bacteria Bacillus cereus Campylobacter Clostridium botulinum Clostridium perfringens E. coli Listeria monocytogenes Salmonella Shigella Staphylococcus aureus Vibrio Yersinia 9 Food Mixture of chemicals Nutrients (99,9%) Toxin Contaminants Additives Proper Food Handling “Key recommendations” for food safety Recommendation 1: CLEAN Clean hands, food-contact surfaces, fruits and vegetables. Do NOT wash or rinse meat and poultry as this could spread bacteria to other12foods. Wash your hands! Handwashing is the most effective way 13 to stop the spread of illness. How to wash hands 1. Wet hands with WARM water. 2. Soap and scrub for 20 seconds. 3. Rinse under clean, running water. 4. Dry completely using a clean cloth or paper towel. 14 Wash hands after … Using bathroom or changing diapers Handling pets Sneezing, blowing nose & coughing AND before ... Touching a cut or open sore 15 Handling food Clean during food preparation Wash cutting boards, knives, utensils and counter tops in hot soapy water after preparing each food and before going on to the next. 16 Recommendation 2: SEPARATE Separate raw, cooked, and ready-to-eat foods while shopping, preparing or storing foods. 17 Use different cutting boards Use one cutting board for fresh produce and a separate one for raw meat, poultry and seafood. 18 When groovy isn’t a good thing Replace cutting boards if they become excessively worn or develop hard-to-clean grooves. 19 Use clean plates NEVER serve foods on a plate that previously held raw meat, poultry or seafood unless the plate has first been washed in hot, soapy water. 20 Recommendation 3: COOK Cook foods to a safe temperature to kill microorganisms. 21 Which ground beef patty is cooked to a safe internal temperature? 23 This IS a safely cooked hamburger, cooked to an internal temperature of 160 degrees F, even though it's pink inside. This is NOT a safely cooked hamburger. Though brown inside, it’s undercooked. Research shows some ground beef patties look done at internal temperatures as low as 135 degrees F. 24 Recommendation 4: CHILL Chill (refrigerate) perishable foods promptly and defrost foods properly. 25 DANGER ZONE Bacteria multiply rapidly between 40 and 140 degrees F. 26 Recommended refrigerator & freezer temperatures Set refrigerator at 40 degrees F or below. Set freezer at 0 degrees F. 27 The THAW LAW Plan ahead to defrost foods. The best way to thaw perishable foods is in the refrigerator. 28 When to leave your leftovers Refrigerated leftovers may become unsafe within 3 to 4 days. If in doubt, toss it out! 29 Recommendation 5: AVOID... Raw (unpasteurized) milk or milk products Raw or partially cooked eggs and foods containing raw eggs Raw and undercooked meat and poultry Unpasteurized juices Raw sprouts Most at risk are infants, young children, pregnant women, older adults and the immunocompromised. 30 31 Should you keep or toss … Pizza left on the counter overnight? 32 Toss it out! Even if you reheat pizza left on the counter overnight, some bacteria can form a heat resistant toxin that cooking won’t destroy. 33 Should you keep or toss … Perishable food left out from the noon meal until the evening meal? 34 Toss it out! Perishable foods – such as meats, gravy and cooked vegetables – should be refrigerated within TWO hours. 35 Should you keep or toss … Cut/peeled fruits and vegetables at room temperature for over TWO hours? 36 Toss it out! Once you have cut through the protective skin of fruits and vegetables, bacteria can enter. Refrigerate cut or peeled fruits and vegetables within TWO hours. 37 Should you keep or toss … Leftovers in the refrigerator for over a week? 38 Toss it out! Refrigerated leftovers may become unsafe within 3 to 4 days. You can’t always see or smell if a food is unsafe. It may be unsafe to taste a food. 39 Remember: 40 41 The dose–response relationship, describes the change in effect on an organism caused by differing levels of exposure or doses to a stressor usually a chemical after a certain exposure time. This may apply to individuals or populations. The science of toxicology is based on the principle that there is a relationship between a toxic reaction (the response) and the amount of poison received (the dose). An important assumption in this relationship is that there is almost always a dose below which no response occurs or can be measured. A second assumption is that once a maximum response is reached any further increases in the dose will not result in any increased effect. The dose response relationship does not hold true, in regards to a true allergic reactions. Allergic reactions are special kinds of changes in the immune system; they are not really toxic responses. The difference between allergies and toxic reactions is that a toxic effect is directly the result of the toxic chemical acting on cells. Allergic responses are the result of a chemical stimulating the body to release natural chemicals which are in turn directly responsible for the effects seen. Measures of exposure Exposure to poisons can be intentional or unintentional. The effects of exposure to poisons vary with the amount of exposure. Usually when we think of dose, we think in terms of taking one vitamin capsule a day or two aspirin every four hours. Contamination of food or water with chemicals can also provide doses of chemicals each time we eat or drink. These measures tell us how much of the chemical is in food, water or air. The amount we eat, drink, or breathe determines the actual dose we receive. Concentrations of chemicals in the environment are most commonly expressed as ppm and ppb. Dose effect parameters Potency: The sensitivity of an organ or tissue to the drug. A highly potent drug evokes a larger response at low concentrations, while a drug of lower potency evokes a small response at low concentrations. It is proportional to affinity and efficacy. Efficacy: The maximum effect that a drug can produce, regardless of dose. Efficacy is the relationship between receptor occupancy and the ability to initiate a response at the molecular, cellular, tissue or system level. The response is equal to the effect. A true assessment of chemical toxicity involves comparisons of numerous doseresponse curves covering many different types of toxic effects The knowledge gained from dose-response studies in animals is used to set standards for human exposure and the amount of chemical residue that is allowed in the environment. Numerous dose-response relationships must be determined, in many different species. Without this information, it is impossible to accurately predict the health risks associated with chemical exposure. With adequate information, we can make informed decisions about chemical exposure and work to minimize the risk to human health and the environment. Manifestation of organ toxicity All organ systems can be targets of toxic exposures. •The accumulation of anti-microbrial drugs and their metabolic byproducts in organs or the exposure of organs to the toxicants can be toxic, leading to organ damage. Target organ toxicity Types of organ specific toxic effects are: •Blood/vascular toxicity •Dermal or occular toxicity •Genetic toxicity •Hepato toxicity •Immuno toxicity •Nephrotoxicity •Neurotoxicity •Reproductive toxicity Blood or cardiovascular toxicity Blood and cardiovascular toxicity results from xenobiotics acting directly On cells circulating blood, bone marrow and heart. Examples of blood and cardiovascular toxicities are: •can result from exposure to noise and to chemicals such as carbon monoxide and tobacco smoke •Hypoxia due to carbon monoxide binding of Dermal toxicity Dermal toxicity may result from direct contact or internal d the skin. Effects range from mild irritation to severe chang Corrosivity, hypersensitivity, and skin cancer. Tetracycline (antimicrobial drug)can cause phototoxicity, Examples of dermal toxicity are: •Dermal irritation due to skin exposure to gasoline •Dermal corrosion due to skin exposure to sodium •Dermal hypersensitivity due to skin exposure to poison iv •Skin cancer due to ingestion of arsenic or skin exposure Eye Toxicity Eye toxicity results from direct contact or internal distribut The cornea and conjunctiva are directly exposed to toxica This rash seen on a forearm is a typical reaction observed when an antibiotic causes phototoxicity. •Corticosteroids may cause cataracts. •Methanol may damage of optic nerves Hepatotoxicity Hepatotoxicity is the toxicity to the liver, bile duct a The liver is particularly susceptible to xenobiotics Supply and its role in metabolism.Thus it is expos Toxicant or its toxic metabolites. The primary form Steatosis: Lipid accumulation in hepatocytes Chemical hepatitis: Inflammation of the liver Hepatic necrosis: Death of the hepatocytes Intrahepatic cholestasis: Back of the bile salts in Ototoxicity •It is basicallly a damage to the ear •ANTIBIOTICS, such as gentamicin, can cause a lose of hearing, or tinnitus ("ringing in the ears") . • Ototoxicity is usually temporary with antibiotics, but permanent hearing damage, while rare, has been reported Immunotoxicity Immunotoxicity is the toxicity of the immune system. It ca Hypersensitivity (allergy and autoimmunity),immunodefic Proliferation (leukemia and lymphoma). The normal funct Is to recognize and defend against foreign invaders. This Of cells that engulf and destroy the invaders or by antibo Materials. e.g •Contact dermatitis due to exposure to poison ivy •Systemic erythematous in workers exposed to hydrazine •Immunosuppresion by cocaine Nephrotoxicity The kidney is highly susceptible to toxicants for two A high volume of blood flows through it and it filtrates Of toxins which can concentrate in the kidneys. It ca Toxicity causing: •Decrease ability to excrete body wastes •Inability to maintain body fluid and electrolyte balan •Decreased synthesis of essential hormones ( e.g. e •Inability to maintain PH balance Neurotoxicity Neurotoxicity represents toxic damage to cells of the System( brain and spinal chord) and the peripheral n (nerves outside the CNS). fluoroquinolones can cause neurotoxicity by directl receptors Respiratory toxicity Respiratory toxicity relates to effects on the upper re (nose,pharynx, larynx, and trachea) and the lower re (bronchi, brochioles and lung alveoli). The primary ty Toxicity are: Pulmonary irritation The primary types of neurotoxicities are: Neuronopathies Axonopathies Demyelination Interference with neurotransmission Reproductive toxicity Reproductive toxicity involves toxic damage to either male or female reproductive system. Toxic effects may cause Decrease libido and impotence Infertility Interrupted pregnancy ( abortion, fatal death, or premature delivery) Infant death or childhood Table 2. Organ Systems Often Affected by Toxic Exposure Organ/System Exposure Risks respiratory asbestos, radon, cigarette smoke, glues Skin dioxin, nickel, arsenic, mercury, cement (chromium), polychlorinated biphenyls (PCBs), glues, rubber cement Liver carbon tetrachloride, methylene chloride, vinyl chloride Kidney cadmium, lead, mercury, chlorinated hydrocarbon solvents cardiovascular carbon monoxide, noise, tobacco smoke, physical stress, carbon disulfide, nitrates, methylene chloride reproductive lead, carbon disulfide, methylmercury, ethylene dibromide hematologic arsenic, benzene, nitrates, radiation neuropsychological tetrachloroethylene, mercury, arsenic, toluene, lead, methanol, noise, vinyl chloride