بهداشت مواد غذایی و سموم

• This document discusses nutrition and food safety in the context of contaminants, presented by Dr. Hamed Jafarri, Assistant Professor at Arak University of Medical Sciences.

Learning Objectives

• To understand the types of environmental and industrial contamination affecting food.
• To recognize the impacts of environmental and industrial food contamination on health.
• To identify strategies for dealing with environmental and industrial food contamination.

Food Hygiene

• Food hygiene involves adhering to health principles and practices during food preparation, production, handling, storage, sale, and consumption.
• It aims to minimize physical, chemical, and biological contamination.
• The goal is to prevent these contaminations from posing a risk to human health.
• Food hygiene ensures the delivery of beneficial food and is a fundamental element of proper nutrition.
• Safe food is an essential component of initial health care.

Toxins in Food

• Contaminants include those used in agriculture, industrial pollutants, natural toxins, and toxins produced during food processing.

Sources of Contamination

• Common sources are polluted water, fossil fuels, radioactive materials, toxic microbial metabolites, chemical residues from agriculture, and drug compounds added to animal feed.

Toxins Used in Agriculture

• Includes pesticides or insecticides, herbicides, fungicides, chemical fertilizers, and veterinary drugs like antibiotics.

Pesticides

• Pesticides in food pose a low acute risk to individuals.
• Only trace amounts of these compounds are typically found in food.
• Most of these substances are not toxic to humans.
• They tend to degrade rapidly in the environment.

Types of Pesticides

• Organochlorines (e.g., Chlordane, DDT): Many of these are now banned.
• Organophosphates (e.g., Malathion, Parathion).
• Carbamates (e.g., Carbaryl, Aldicarb).
• Botanicals (e.g., pyrethrum, nicotine).
• Inorganic compounds (e.g., arsenic compounds).

Organochlorines

• DDT is a common example.
• They accumulate in fatty tissues.
• They can be transferred into breast milk.
• They can transfer into the milk produced by livestock.

Organophosphates

• They inhibit cholinesterase enzymes.
• They are neurotoxic.
• Common examples include malathion, parathion, phosphamidon, and dimethoate.
• Transmission happens through ingestion, inhalation, and skin absorption.
• They are sometimes mistaken for substances like sugar and salt.

Carbamates

• Aldicarb-related acute poisoning happened following the consumption of contaminated watermelons in 1985 in the US, due to farmers illegally using this substance.
• Aldicarb poisoning is also related to consuming hydroponically grown cucumbers.
• Symptoms of Aldicarb poisoning include nausea, vomiting, diarrhea, and mild neurological effects such as headache, dizziness, blurred vision, and imbalance.

Herbicides

• They include chlorophenoxy compounds, dinitrophenols, bipyridyl compounds, carbamates, and triazines.
• There is generally no risk to consumers from consuming residue of these compounds in foods.
• They can be selectively toxic to plants.
• Bipyridyl versions (Paraquat and Diquat) are not selective to plants, possessing strong toxic effects, causing significant effects on lungs in humans.

Fungicides

• The risk of exposure to these compounds and related hazards is minimal.
• Mercury compounds and hexachlorobenzene are exceptions.
• Mild mercury poisoning includes gastrointestinal and skin symptoms such as acrodynia and itching.
• Severe hexachlorobenzene poisoning symptoms include porphyria cutanea tarda, skin lesions, alopecia, hepatomegaly, and thyroid enlargement.
• Overall fatality rate is about 10%.

Chemical Fertilizers

• Includes nitrogen and phosphorus compounds.
• Nitrogen is converted to nitrite and then nitrate in the soil.
• Infants are highly susceptible to nitrite and nitrate poisoning.
• Symptoms of low-dose nitrite ingestion entail facial flushing, extremity warmth, gastrointestinal disturbances, and headaches.
• Symptoms of high-dose nitrite ingestion include cyanosis, methemoglobinemia, nausea, vomiting, abdominal pain, vascular collapse, and potentially death.
• The lethal dose of nitrate in adults is 1 gram.

Antibiotics

• Concerns exist over the use of drugs and antibiotics in animals.
• The primary concern relates to penicillin.
• Penicillin is a broad-spectrum antibiotic used in both humans and animals.
• Allergic reactions to low levels of penicillin in food are considered unlikely.

Chemicals Transferred from Food Containers

• Includes Bisphenol A (BPA).
• Includes copper, iron, lead, zinc, tin, nickel.
• Acidic foods in metal containers and packaging can cause heavy metals to leach into the food.

Bisphenol A (BPA)

• BPA is used in the production of plastic compounds (polycarbonate resins) and epoxy resins.
• It is found in baby bottles, water bottles, and the plastic liners of metal food and beverage cans.
• Negative impacts of BPA include affecting brain, behavior, and prostate function in fetuses, infants, and children.
• Adults face a lower risk of these problems.

Copper (Cu)

• The safe copper intake is 0.05 mg per kilogram of body weight.
• Contamination happens due to storing foods in unlined and corroded copper cookware.
• Acute poisoning symptoms include nausea, vomiting, melena, and hematemesis.
• A lethal dose of copper sulfate for humans is about 10 grams.

Iron (Fe)

• Contamination happens through the preparation and prolonged storage of food in uncoated iron cookware and corroded containers.
• Change in food taste prevents consuming such foods, preventing development of poisoning.
• Children are more susceptible to toxicity following iron supplements.

Zinc (Zn)

• The required zinc intake is 0.2-0.3 mg per kilogram of body weight.
• Storing acidic foods and drinks in galvanized containers can cause acute zinc poisoning.
• Zinc poisoning is notably associated with nausea.
• Related symptoms: mouth, throat, and abdominal irritation, nausea, vomiting, dizziness, and fainting.

Lead (Pb)

• Lead exposure is a widespread public health concern.
• One exposure route is through lead-containing cans.
• Lead poisoning occurs if the blood lead level is between 0.6 and 1.0 micrograms per liter.
• Children are especially vulnerable.
• It affects the nervous system, kidneys, and bones.
• Associated with anemia and neurotoxic disorders.

Tin (Sn)

• Metal food cans are usually coated with tin.
• If these cans are used for acidic foods and drinks, the inner surface is lacquered to prevent tin from leaching into the food.
• If acidic foods, such as tomato juice and fruit juice, are stored in unlacquered containers, acute tin poisoning may result in certain instances.
• Early signs and symptoms include nausea, stomach cramps, vomiting, diarrhea, and headaches.
• Symptoms manifest between 30 minutes and 2 hours after ingesting the food.

Industrial Pollutants

• Mercury.
• Polychlorinated biphenyls (PCBs).
• Polybrominated biphenyls (PBCs).

Mercury

• Wastewater from some industries can contaminate the environment with mercury.
• Anaerobic bacteria can produce methane, dimethyl mercury, and methyl mercury.
• Methyl and dimethyl mercury can easily be absorbed and accumulate in red blood cells and the central nervous system.
• Fish and other marine products have a high potential for mercury contamination.

Mercury - Minamata Disease

• It is caused by eating fish contaminated with methyl mercury.
• Symptoms include neurotoxic effects, tremors, and kidney failure.
• Effects of mercury poisoning differ, all implying nervous system impairment.
• Maximum acceptable mercury levels in fish should not exceed 0.5 ppm; daily intake by humans should not exceed 45 micrograms.

Polychlorinated Biphenyls (PCBs) and Polybrominated Biphenyls (PBCs)

• PCBs and PBCs are toxic industrial pollutants that persist in the environment.
• Several situations involving their contamination of food products have happened.
• They dissolve in fat and accumulate in the fat reserves of living things, especially fish.
• While there's little concern regarding severe poisoning brought on by these substances, there's more worry about their detrimental effects over prolonged durations.
• They are slowly eliminated from the body, raising concerns over their long-term consequences in contaminated diets.

PCBs - Yusho Syndrome

• PCB poisoning has been documented in Japan following the consumption of rice bran oil that was contaminated.
• Specific symptoms encompass weakness, limb numbness, eyelid swelling, eye discharge, darkened skin, and liver damage.
• Acute poisoning is characterized by a dose of 0.5 grams.
• Chronic effects appeared in many sufferers up to 8 years post-consumption.
• Long-term effects encompass menstrual irregularities, exhaustion, headaches, fever, coughing, gastrointestinal problems, and sensory impairment.

Cadmium (Cd)

• Cadmium is rapidly and uniformly absorbed by plants, with extensive distribution in their tissues.
• In animals, it is found mainly in internal organs like the liver, kidneys, and also in milk.
• Cadmium accumulates in the kidneys at levels of 0.02 to 0.03 percent of kidney weight, causing damage in the kidneys.
• Nausea, diarrhea, and malaise can develop 10 minutes after consuming contaminated food.

Arsenic

• Arsenic is present in low concentrations in most foods because it is widespread in the environment.
• Drinking water typically contains around 0.5 ppm of arsenic in many countries.
• Levels may reach about 1 mg/L in some hot springs and mineral waters.
• Levels rarely go over 1 ppm in foods, except seafood.
• Mussels on the English coast have been found to contain 170 ppm of arsenic.

Summary

• Chemical pollutants in food significantly endanger human health.
• Metal contamination and pollution from industrial processes present critical threats to human health and safety.
• Chronic illnesses like cancer, neurological disorders, anemia, and liver and kidney conditions can arise from prolonged exposure to industrial and environmental pollutants.
• Public awareness and industry regulation can significantly reduce the incidence of contamination and associated diseases.