This set of slides crisply present the various types of contaminants and toxicants associated with food.

1. FOOD CONTAMINANTS ANDFOOD CONTAMINANTS AND
NATURALLY OCCURRINGNATURALLY OCCURRING
TOXICANTSTOXICANTS
Monika Jain
Department of Food Science and Nutrition
Banasthali Vidyapith, Rajasthan, India

2. Monika Jain
Food Contamination- DefinitionFood Contamination- Definition
CODEX ALIMENTARIUS-
 “Any substance not intentionally added to food,
which is present in such food as a result of the
production (including operations carried out in
crop husbandry, animal husbandry and
veterinary medicine), manufacture, processing,
preparation, treatment, packing, packaging,
transport or holding of such food as result of
environmental contamination”

3. Monika Jain
Examples of Food ContaminationExamples of Food Contamination
Food can get
contaminated by-
 Water used for
cooking/washing
 Soil in which food is
grown
 Container used for
storage, preparation,
service
 Personnel handling food
at various stages
 Dioxin contaminated
chickens
 Hormone injected cattle
 GM varieties of maize
 Animal carcasses used to
make animal feed and
subsequent mad cow
disease in animals
consuming the feed
 Pesticide residue
containing mineral
water, soft drinks

4. Monika Jain
Classification of Contaminants inClassification of Contaminants in
FoodstuffsFoodstuffs
Contaminants
in foodstuffs
PHYSICAL BIOLOGICAL CHEMICAL

5. Monika Jain
Contaminants, Natural orContaminants, Natural or
otherwise..otherwise..
CONTAMINANTS
Naturally occurring toxicants
(toxicants in plants, animal food, anti nutritional factors)
Environmental contaminants
(biological contaminants, pesticide residues, vet drug residues, heavy metals)
Miscellaneous
(dioxins, acrylamide, contaminants from plastic)

6. Monika Jain
Food Contaminants
of Natural Origin
Toxicants in
animal foods
Toxicants in
plant foods
Anti nutritional
substances
•Shellfish toxins
•Other seafood toxins
•Toxic amino acids
•Toxic alkaloids
•Cyanogenic glycosides
•Toxic mushrooms
•Enzyme inhibitors
•Phytates
•Tannins
•Oxalates
•Goitrogens
•Haemagglutinins

7. Monika Jain
Seafood ToxinsSeafood Toxins
Most potent toxins are found in marine
products, esp., shellfish
Clams, oysters, scallops and mussels feed
on plankton and algae in the sea
Some of the plankton is toxic for us
Four separate types of shellfish poisoning
have been identified

8. Monika Jain
Types of Shellfish PoisoningTypes of Shellfish Poisoning
 PARALYTIC SP
 Most severe symptoms
of all
 Causative agent is
Saxitoxin
 It is neurotoxin produced
by Gonyaulax catenella
 Symptoms in 30 mins-
headache, floating
feeling, dizziness,
tingling, burning,
numbness, difficulty in
swallowing & speaking.
Death due to paralysis of
resp. sys.
 DIARRHOEIC SP
Mild gastro intestinal
symptoms
 NEUROTOXIC SP
Both gastrointestinal and
neurological symptoms
 AMNESIC SP
Gastrointestinal and
neurologic disorders.
Caused by the presence
of an unusual amino acid

9. Monika Jain
Other Toxicants Present inOther Toxicants Present in
SeafoodSeafood
Ciguatera toxin, a polyether, is found in
blue algae and protozoans. It’s known to
affect sensory, motor and muscular
activities.
Ingestion of improperly handled and stored
seafood causes Scombroid poisoning.
Maitoxin has been implicated. It releases
neurotransmitters and increases the
contraction of smooth, cardiac and skeletal
muscle.

10. Monika Jain
Tetrodotoxin (non pr neurotoxin) causes
Pufferfish poisoning. Symptoms are
cardiovascular and neurologic in nature.
Hallucinogenic fish poisoning can occur
with the ingestion of a no. of fish species.
 Miscellaneous shellfish poisonings
include oyster, abalone and red whelk
poisoning. Starfish ingestion may be
associated with nausea and vomiting as a
result of asteritoxin.

11. Monika Jain
Toxicants in Plant FoodsToxicants in Plant Foods
 Favism- Haemolytic anaemia after consuming
Fava beans. Initial symptoms include headache,
nausea, vomiting, pain and fever. This is
followed by Hb in urine, jaundice and death.
 Gossypol- Toxicant present in cottonseed may
come in cottonseed oil
 Erucic acid- linked to heart disease, is found in
mustard and rapeseed oil.
 Cucurbitacins- Toxin in bitter cucurbits. Results
in symptoms of severe cramps, diarrhoea and
collapse.

12. Monika Jain
Specific Toxicants found in PlantSpecific Toxicants found in Plant
FoodsFoods
TOXIC AMINO ACIDS
 Lathyrus sativus seeds contain BOAA. It causes
lathyrism.
 It is an excitotoxin, capable of over stimulating
& destroying nerve cells.
 Causes upper motor neuron disease.
 Classical symptom is spastic paraplegia,
paralysis of lower limbs.
 Consumption in lower quantities- painful spasms
in calf muscles, heaviness of lower limbs, pain in
knee and ankle, difficulty in walking.

13. Monika Jain
TOXIC ALKALOIDSTOXIC ALKALOIDS
 Alkaloids are N heterocycles which occur mainly
in plants as their salts of common carboxylic
acids.
 Potatoes contain glycoalkaloids, eg., solanine.
Consumption causes diarrhoea, vomiting,
abdominal pain, restlessness.
 Consumption of mustard oil with argemone oil
(contains toxic alkaloid sanguinarine) can cause
epidemic dropsy, in which there is oedema over
ankles, gastrointestinal disturbances & vascular
& cardiac complications which can result in
death.

14. Monika Jain
CYANOGENIC GLYCOSIDESCYANOGENIC GLYCOSIDES
Cassava is a rich source of CG
(Linamarin). It may be hydrolysed
chemically or enzymatically to yield the
poisonous hydrogen cyanide.
Acute cassava poisoning- headache,
breathlessness, gasping, paralysis, muscle
weakness, coma & death.
Lima beans contain cyanide precursors.
These inhibit oxidative processes of cells.

15. Monika Jain
MUSHROOM POISONINGMUSHROOM POISONING
Caused by consumption of raw or cooked
fruiting bodies of a no. of species of higher
fungi. Four types-
Protoplasmic poisons
Neurotoxins
Gastrointestinal irritants
Disulfirum- like toxins

16. Monika Jain
Anti Nutritional Factors in FoodAnti Nutritional Factors in Food
Interfere with the assimilation of nutrients
in the body
Protease inhibitors
Phytates
Oxalates
Tannins
Lectins
Goitogens

17. Monika Jain
Protease InhibitorsProtease Inhibitors
Interfere with the action of trypsin and
chymotrypsin
Found in oats, wheat, barley, maize, onion,
beetroot, peanuts
Trypsin inhibitors are found in legmes,
white of an egg
Raw soyabeans have high levels of TI.
These can cause growth retardation &
hypertrophy of pancreas.

18. Monika Jain
HaemagglutininsHaemagglutinins
 Globulin type of proteins
 Present in field bean, white bean, horse gram
 Have the property of agglutinating RBCs
 Agglutinins combine with the cell lining of
intestinal wall & thus interfere with nutrient
absorption
 Symptoms are nausea, vomiting , diarrhoea,
growth depression, decreased food intake, death.

19. Monika Jain
PhytatesPhytates
Unrefined cereals and millets are richest
sources of phytates
Phytates in cereals form insoluble
complexes with minerals such as Fe, Mg,
Zn & Ca & contibute to their poor
absorption from cereal based diets
Germination and overnight soaking reduce
phytate content

20. Monika Jain
TanninsTannins
 Interfere with the absorption of iron and reduce
the availability of proteins by binding to them
 Present in high amounts in seed coat of most
legumes, spices, tamarind, turmeric, certain
vegetables, fruits and particularly teaa
 A typical Indian diet may contain 2-3 g of
tannins
 Removal of seed coat of legumes, exclusion of
tamarind, avoiding tea with meals improve iron
absorption & reduce tannin content

21. Monika Jain
OxalatesOxalates
Mostly present in form of Ca salts
Interfere with Ca absorption
Hyperoxaluria- kidney stones
Rich sources are GLVs & some legumes
like horse gram & kesari dhal

22. Monika Jain
Goitrogens/Anti ThyroidGoitrogens/Anti Thyroid
SubstancesSubstances
Interfere with the uptake of iodine by the
thyroid gland
Can contribute to development of IDD
when I intakes are marginal
Thiocyanates, isothiocyanates & their
derivatives are the chief goitrogens present
in leaves & vegetables belonging to
Brassica genus & family Cruciferae

23. Monika Jain
ENVIRONMENTALENVIRONMENTAL
CONTAMINANTSCONTAMINANTS
ENVIRONMENTAL
CONTAMINANTS
BIOLOGICAL
•Fungi
•Fungal toxins
•Bacteria and their toxins
PESTICIDE RESIDUES
Found in-
•Milk
•Grains
•Oil
•Bottled water
•Vegs & fruits
VET DRUG RESIDUES
Found in-
•Milk
•Milk pdts
•Meat
•Meat pdts
METALLIC
Nickel

24. Monika Jain