FOOD TOXICANTS DR NAVYA N ASSIS TA N
- Slides: 30
FOOD TOXICANTS DR NAVYA N ASSIS TA N T PROFESSO R DEPART MENT OF C OMMUNIT Y MEDICINE
SPECIFIC LEARNING OBJECTIVES At the end of the class the student should be able to 1. Describe the classification of food borne diseases 2. List the various food toxicants 3. Briefly describe the effect of each food toxicant on health
FOOD BORNE DISEASES Foodborne intoxications Due to naturally occurring toxins 1. Lathyrism 2. Endemic ascitis Bacterial toxins 1. Botulism 2. Staphylococcal poisons
Toxins from fungi 1. Aflatoxin 2. Ergot 3. Fusarium toxins
Food borne chemical poisoning ◦ Heavy metals. eg. v Mercury (fish) v Cadmium (shell fish) v Lead (canning) ◦ Oils, petroleum derivatives and solvents (trycresyn phosphates) ◦ Asbestos ◦ pesticides
Food borne infections Bacterial diseases • Typhoid • Paratyphoid • Salmonellosis • Staphylococcal infections • C. perfringens • Botulism • B. cerus food poisoning • E. coli diarrhea • Non cholera vibros • V. parahimoliticus • Shigellosis • Brucellosis • Streptococcus
• Viral Diseases v. Viral hepatitis v. Gastro enteritis • Parasites v. Taeniasis v. Hydatiosis v. Trichinosis v. Ascariasis v. Amoebiasis v. Oxyuriasis
LATHYRISM §Lathyrism- paralysing disease- humans and animals. §Humans- neurolathyrism- affects the nervous system § Animals- osteolathyrism (odoratism)- pathological changes- bones- skeletal deformities §Neurolathyrism- crippling disease- nervous system Characterised: § Gradually developing spastic paralysis- lower limbs, § Adults consuming- pulse- Lathyrus sativus- large quantities
CLINICAL FEATURES Disease affects- young men between- age of 15 to 45 years and manifests itself in stages : 1. LATENT STAGE 2. NO STICK STAGE 3. ONE STICK STAGE 4. TWO STICK STAGE 5. CRAWLER STAGE
CLINICAL FEATURES (a) Latent stage : §Individual- apparently healthy- subjected to physical stress- ungainly gait. §Neurological examination- characteristic physical signs. §This stage – important- preventive aspect- if the pulse- withdrawn- dietcomplete remission of the disease. (b) No-stick stage : Patient walks- short jerky steps without the aid of a stick. (c) Onestick stage- Patient walks- crossed gait with a tendency to walk on toes. §Muscular stiffness makes it necessary to use a stick to maintain balance.
CLINICAL FEATURES (d) Two stick stage : symptoms- more severe. Excessive bending of knees and crossed legs- patient needs two crutches for support. The gait is slow and clumsy- patient gets tired easily after walking a short distance. (e) Crawler stage : Erect posture- impossible- knee joints cannot support the weight of the body. Atrophy of the thigh and leg muscles. The patient is reduced- crawling by throwing his weight on his hands
INTERVENTIONS 1. VITAMIN C PROPHYLAXIS 2. BANNING THE CROP 3. REMOVAL OF TOXIN 4. EDUCATION 5. GENETIC APPROACH 6. SOCIO-ECONOMIC CHANGES
INTERVENTIONS (a) Vitamin C prophylaxis: certain instances- damages- repaired by the daily administration of 500 -1000 mg of ascorbic acid for a week or so. (b) Banning the crop : extreme step not feasible- immediate implementation. • The Prevention of Food Adulteration Act in India-banned lathyrus in all forms - whole, split or flour. • But ban- not operative where it is needed- Madhya Pradesh, Bihar, Orissa and Gujarat- pulse is widely grown. • If not possible to avoid consuming khesari dhal- proportion of the dhal -never form more than a quarter of the total amount of cereals and pulses eaten per day.
INTERVENTION (c) Removal of toxin q. Steeping Method : toxins- water soluble- removed by soaking the pulse in hot water. - can be practised at home. § A large quantity- water boiled- pulse soaked in hot water for 2 hours-soaked water is drained off completely. §Pulse -washed again with clean water, then drained off and dried- sun. §Pulse- then used for consumption. §Drawback- entails loss of vitamins and minerals
INTERVENTION (c ) Removal of toxin q. Parboiling : Improved method of detoxicating. • suitable for large scale operation. §Simple soaking in lime water over- night followed by boiling- destroy the toxin. §This treatment- destroys trypsin inhibitors.
INTERVENTIONS (d) Education : dangers of consuming this pulse and need for removing toxin before consumption. (d) Genetic approach : Certain strains- very low levels of toxin (0. 1%). Selective propagation and cultivation of such strains - most effective way eradicate lathyrism without any drastic change- habits of the people. §Low toxin varieties- Indian Agricultural Research Institute. New Deihi. (e) Socio-economic changes: can root out lathyrism
AFLATOXINS §Group mycotoxins - certain fungi- Aspergillus flavus and A parasiticus. §These fungi infest- foodgrains- groundnut, maize, parboiled rice, sorghum, wheat, rice, cotton seed and tapioca- improper storage, §Aflatoxins- B 1 and G 1 - most potent hepatotoxins, in addition- being carcinogenic. §Most important factors affecting formation of toxin- moisture ( >16%) and temperatures (11 to 37 o. C) favour toxin formation. § Aflatoxin B 1 - detected in samples of breast milk and urine- children suffering from infantile cirrhosis, §Attempts- relate aflatoxin with human liver cirrhosis
AFLATOXIN §Control and preventive measures : 1. Proper storage after drying 2. Moisture content- kept below 10 per cent. 3. If the food is contaminated- not be consumed. 4. Educate the local population- health hazards of consuming contaminated foodgrains.
ERGOT §Field fungus – claviceps fusiformis §Foodgrains such as bajra, rye, sorghum, and wheat - have a tendency §Fungus grows- blackish mass and the seeds become black and irregular and harvested along with food grains § Acute but rarely fatal and include nausea, repeated vomiting, giddiness and drowsiness extending §sometimes for periods up to 24 to 48 hours after the ingestion §Chronic - Causes painful cramps and vasoconstriction gangrene §Infects bajra and wheat §Prevention - floating in 20% salt solution/ hand picking/ air floatation
EPIDEMIC DROPSY -Mustard oil is mixed with argemone oil -Toxin – sanguinarine- accumulation of pyruvic acid – blood -Symptoms are - Sudden, non inflammatory- bilateral swelling of leg and feet Diarrhea dyspnoea Cardiac failure -Tests - Nitric acid – orange red colour - Paper chromatography
ENDEMIC ASITIS Weeds - Crotolaria seeds are mixed with millet panicum miliare (gondhli) Hepatotoxins Prevention ◦ deweeding ◦ Seiving the millet ◦ Educating the people
SUMMARY ? ? ?
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