- flame atomic absporption spectrophometry
- electrothermal atomic absorption spectrophometry
- inductively coupled plasma atomic emission spectrometry
- atomic fluorescence spectrometry
Thursday, July 12, 2007
anaytical methods for metal detection
Monday, July 9, 2007
detection methods
Mycotoxins
- TPC
- HPLC
- ELISA
Paralytic shellfish toxins (PSPs)
- HPLC (oxidation and fluorscence assay)
- Capillary electrophoresis
Diarrhetic shellfish
- LC
- Mass spectrometry (can use to detect all but expensive)
Herbicide residue/fungicide reside
- LC
- GC
- TPC
- HPLC
- ELISA
Paralytic shellfish toxins (PSPs)
- HPLC (oxidation and fluorscence assay)
- Capillary electrophoresis
Diarrhetic shellfish
- LC
- Mass spectrometry (can use to detect all but expensive)
Herbicide residue/fungicide reside
- LC
- GC
Saturday, July 7, 2007
meaning
An enterotoxin is a protein toxin released by a micro-organism in the lower Intestine. Enterotoxins are frequently cytotoxic and kill cells by altering the permeability of the epithelial cells of the intestinal wall. They are mostly pore forming toxins, secreted by bacteria, that assemble to form pores in cell membranes. This causes the cells to die.
A neurotoxin is a toxin that acts specifically on nerve cells – neurons– usually by interacting with membrane proteins such as ion channels.
meaning from: http://en.wikipedia.org/wiki/Enterotoxins
http://en.wikipedia.org/wiki/Neurotoxins
A neurotoxin is a toxin that acts specifically on nerve cells – neurons– usually by interacting with membrane proteins such as ion channels.
meaning from: http://en.wikipedia.org/wiki/Enterotoxins
http://en.wikipedia.org/wiki/Neurotoxins
bacterial toxins
Staphylococcus aureus intoxication
- One of the most important causes of food-borne disease worldwide.
- It is gram positive, nonmotile and non-spore forming cocci that forms 5entertoxins ( A-SEA, SEB, SEC, SED, SEE)
- Entertoxins are simple proteins that have high heat stability
- Growth increases at optimum pH and temperature
- Foods containing S.aureus at level of 5 X 105/g may cause S.aureus intoxication
Signs and symptoms
- begin 1-6hrs of consumption
- nausea, vomiting, abdominal cramps, diarrhea
Preventive measures
- practice hygiene practices
- reduced post-cooking contamination of high protein foods and eliminating prolonged storage of cooked food at room temp before eating
Clostridium botulinum intoxication
- gram positive rod-shaped anaerobic bacteria capable of forming heat resistance spores
- 6types of heat labile neurotoxins : A, B, C, D, E, F and G
- Type A and B : more likely to cause botulism in humans
- Example of food containing type A and B: beans and corns
- Type E : isolated from soil, seawater, fish intestines and sea or lake sediments
- Type F : from liver paste
- Botulinum toxin is a super toxin compound.
- Prevention : heating at 79oC for 20mins or at 85oC for 5mins
Signs and symptoms
- Appears 12-24hrs following consumption
- headache, blur vision, dizziness
- causes death from periods 24hrs to 2-3weeks
Preventive measures
- proper home preservation of foods
- discard all swollen and damaged canned products
Bacillus cereus intoxification
- gram positive, rod shaped, spore forming aerobe
- found in cereals, milk, herbs and spices
- 2types of enterotoxins : emetic and diarrheagenic
- Diarrheagenic toxins is a protein that is produced by actively growing cells
- Activated by enzymes like trypsin or exposure to 56oC or more than 30mins
- Emetic toxin is stable to heat, pH and pepsin enzymes
Clostridium perfringens intoxication
- causes foodborne infections followed that subsequently lead to sporulation
- lecithinase, an enterotoxin released during sporulation
- five antigenically (toxicologically) types: type A through E
- type A: involve in foodborne gastroenteritis in humans
- type C: produces 2 different toxins; lethal-necrotizing and hemolytic
book: introduction to toxicology and food
- One of the most important causes of food-borne disease worldwide.
- It is gram positive, nonmotile and non-spore forming cocci that forms 5entertoxins ( A-SEA, SEB, SEC, SED, SEE)
- Entertoxins are simple proteins that have high heat stability
- Growth increases at optimum pH and temperature
- Foods containing S.aureus at level of 5 X 105/g may cause S.aureus intoxication
Signs and symptoms
- begin 1-6hrs of consumption
- nausea, vomiting, abdominal cramps, diarrhea
Preventive measures
- practice hygiene practices
- reduced post-cooking contamination of high protein foods and eliminating prolonged storage of cooked food at room temp before eating
Clostridium botulinum intoxication
- gram positive rod-shaped anaerobic bacteria capable of forming heat resistance spores
- 6types of heat labile neurotoxins : A, B, C, D, E, F and G
- Type A and B : more likely to cause botulism in humans
- Example of food containing type A and B: beans and corns
- Type E : isolated from soil, seawater, fish intestines and sea or lake sediments
- Type F : from liver paste
- Botulinum toxin is a super toxin compound.
- Prevention : heating at 79oC for 20mins or at 85oC for 5mins
Signs and symptoms
- Appears 12-24hrs following consumption
- headache, blur vision, dizziness
- causes death from periods 24hrs to 2-3weeks
Preventive measures
- proper home preservation of foods
- discard all swollen and damaged canned products
Bacillus cereus intoxification
- gram positive, rod shaped, spore forming aerobe
- found in cereals, milk, herbs and spices
- 2types of enterotoxins : emetic and diarrheagenic
- Diarrheagenic toxins is a protein that is produced by actively growing cells
- Activated by enzymes like trypsin or exposure to 56oC or more than 30mins
- Emetic toxin is stable to heat, pH and pepsin enzymes
Clostridium perfringens intoxication
- causes foodborne infections followed that subsequently lead to sporulation
- lecithinase, an enterotoxin released during sporulation
- five antigenically (toxicologically) types: type A through E
- type A: involve in foodborne gastroenteritis in humans
- type C: produces 2 different toxins; lethal-necrotizing and hemolytic
book: introduction to toxicology and food
Thursday, July 5, 2007
mycotoxins found in food and animal feed
Aflatoxins
-Possible adverse effects on livestock health and productivity
-Toxins produced by species of Aspergillus, mainly A.flavus and A. parasiticus
-There are 17toxins present but only 4 considered widespread and toxins ( ie aflatoxins B1, B2, G1. G2)
-Pure aflatoxins are destroyed by UV radiations, unstable at pH<3>10 and in the presence of oxidizing components.
-The toxins have native fluorescence, which is used for their analysis and for the sorting of contaminated units.
-Aflatoxins occur in wide variety of commodities including cereals, nuts and oilseeds
Ochratoxin A (OTA)
- Variety of moulds included in the genera Aspergillus
- Ochratoxin A contaminated crops include cereal such as barley and maize, wheat and oat.
- In cereals, OTA is produced more frequently by Penicillium than Aspergillus (generally occurs as storage contamination)
Trichothecenes
- Wide group of mycotoxins produced by various species of different genera: Fusarium, Myrothecium, Stachybotrys, Trichoderma, Cephalosporium, Trichothecium and Verticimonosporium ( Betina, 1993)
Fumonisins (FBs)
- FBs are mycotoxins mainly produced by Fusarium verticillioides, Nirenberg, Fusarium proliferatum
- Occurs in mainly maize and maize based food products at levels that could affect human and animal health.
book: pesticide, veterinary and other residues in food
-Possible adverse effects on livestock health and productivity
-Toxins produced by species of Aspergillus, mainly A.flavus and A. parasiticus
-There are 17toxins present but only 4 considered widespread and toxins ( ie aflatoxins B1, B2, G1. G2)
-Pure aflatoxins are destroyed by UV radiations, unstable at pH<3>10 and in the presence of oxidizing components.
-The toxins have native fluorescence, which is used for their analysis and for the sorting of contaminated units.
-Aflatoxins occur in wide variety of commodities including cereals, nuts and oilseeds
Ochratoxin A (OTA)
- Variety of moulds included in the genera Aspergillus
- Ochratoxin A contaminated crops include cereal such as barley and maize, wheat and oat.
- In cereals, OTA is produced more frequently by Penicillium than Aspergillus (generally occurs as storage contamination)
Trichothecenes
- Wide group of mycotoxins produced by various species of different genera: Fusarium, Myrothecium, Stachybotrys, Trichoderma, Cephalosporium, Trichothecium and Verticimonosporium ( Betina, 1993)
Fumonisins (FBs)
- FBs are mycotoxins mainly produced by Fusarium verticillioides, Nirenberg, Fusarium proliferatum
- Occurs in mainly maize and maize based food products at levels that could affect human and animal health.
book: pesticide, veterinary and other residues in food
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