1. Food Additives Foods, Facts & Fallacies YSCN 0006 http://web.hku.hk/~lramsden/fff.html

2. Additives  What do we eat?  Fresh food versus processed food.  Changing patterns of food consumption.  Longer storage and processing  Need to maintain food quality

3. What are additives?  Substances added to food that are not naturally present  Not nutritive  Original aim usually preservation  Later to enhance food appearance  and enhance food quality

4. Types of Additives and their Functions

5. Food Regulation  US GRAS system  Generally Recognised As Safe  Introduced in 1958 to approve established food ingredients  New additives must be approved by FDA  Delaney Clause to prohibit any substance known to cause cancer

6. Additive Testing  Relies on animal tests to NOEL  No Observable Effect Level = highest dose of additive with no effect on animal  Reduced by a factor of 100 to give safety margin for humans

7. E number system  European system for approved food additives  E classification shows the additive is safe for use in food  Internationally recognised and also used in other countries

8. E numbers

9. Earliest Additives  Preservatives  Sodium Chloride, Salt  Used for 10,000 years to preserve meat products  Salt reduces water availability for bacteria to grow  Crude salt is contaminated with sodium nitrate  Additional use of smoke

10. Traditional Additives  Used for thousands of year  Salt and saltpetre  Smoke  Honey  Vinegar  Herbs & Spices  Natural food colourings  Calcium carbonate

11. E 250 Sodium Nitrite  Sodium nitrate contaminant of crude salt  Found to cause pinkish colour in meat  Sodium nitrite more effective  On high temp cooking can be converted to carcinogenic compounds nitrosoamines.  Potent inhibitor of anaerobic metabolism  Prevents growth of major food pathogen  Clostridium botulinum

12. Clostridium botulinum  Common soil bacteria  Anaerobe can only grow well when no oxygen present  Spores heat resistant to 120°C for 3mins  Bacteria produces protein toxin  1µg fatal, respiratory paralysis and cardiac failure

13. Meat colour  Fresh meat ~ purplish red  Exposed meat, bright red oxymyoglobin  Later turns to metmyoglobin, gray or brown  Nitrite reacts to form nitrosomyoglobin  After cooking – nitrosohaemochrome  pinkish red in colour

14. Cured meat  Pickled in salts,  Salt, sodium nitrite, ascorbic acid, sugar  Meat submerged in strong solution  Or injected by machines with multiple needles  10 days at 4°C

15. Smoking  Wood fire, produces anti bacterial compounds  Provides surface coating and protection  Colour and flavour  Hams, heated to 60°C  Not sterile, must be refrigerated,  But can be eaten raw  Bacon, only heated to 52°C  Cannot be eaten raw

16. Sausages  Ground meat, low quality off-cuts  Natural casing, eg. sheep intestine  Stuffed + spices, salt, sugar, ice  Sodium nitrite to inhibit Clostridium botulinum

17. Frankfurters, hot dogs  Meat comminuted  Ground very finely to form meat emulsion  30% fat, 10% water  stuffed in cellophane casings to form links  smoked or cooked to 75°C  De-skinned, passed through hot water and skins peeled off by machine.

18. Spoilage  Become slimy  Surface growth of yeasts and bacteria  Turn green  lactobacter releasing hydrogen peroxide  Reacts with nitrosohaemochrome  oxidises it to a green colour

19. More Preservatives  E200 Sorbic Acid, soft drinks, yoghourt.  E210 Benzoic acid, jams, creams  E220 Sulphites, SO 2 wine, vegetables, drinks  E230Diphenyl, fruit  E234Nisin, cheese  E239HexamineFish  E280Propionic acidBread

20. Antioxidants  Chemical preservation  Most important for fats  E300Ascorbic acid (vitamin C)  E306Tocopherol (Vitamin E)  E320BHAmeat products, dairy products  E321BHT meat products, dairy products

21. Flavour  Artificial Sweeteners  sucrose1  cyclamate30  saccharin300  aspartame180  sucralose600  alitame2000  thaumatin2500

22. Artificial Flavours  Mimics of natural flavours using complex mixes of pure chemicals  Synthetic banana flavour  amyl acetate  amyl butartae  ethyl butartae  isoamyl acetate  isoamyl butarate  linalool  + 15 others in lesser quantities

23. Flavour enhancer  E621 monosodium glutamate  amino acid - glutamine

24. 19th century  Increased urbanisation & food processing  Adulteration  Use of cheap substitutes  Colour & flavour enhancers  Sometimes dangerous  1857 survey of confectionary found colours:  Lead chromate  Mercuric sulphide  Copper arsenite

25. Food Colours  Preserved Vegetables  Chlorophyll, green pigment in plants is unstable  Green colour from copper salts due to cooking under acid conditions in copper pans

26. Confectionary  Colouring to enhance consumer appeal  Natural  Inorganic  Synthetic

27. Natural Colours  Caramel, brown from burnt sugar,  most widely used colour,  not always classified as an additive  Carotenoids, orange/yellows  Anthocyanins, reds & blues  Betalaines, red/purple  Turmeric, root of turmeric plant, yellow  Cochineal, insects from cactus, scarlet

28. Synthetic Colours  Yellow TartrazineE102  Sunset yellowE110  Red Red 2GE128  Ponceau 4RE124  AmaranthE123  Blue Brilliant Blue FCFE133  Green Food Green SE142  Brown Chocolate BrownE155

29. Dye problem  Many organic chemicals with bright colours found to be carcinogenic  Flat shape allows them to interfere with DNA helix  Usually found by effects on people making them not those eating them  e.g. Butter yellow  Not allowed to be used in foods

30. Bread  Flour whitening  calcium carbonate  Anti caking agents  ammonium citrate  Dough enhancers  stearate  Leavening agents  baking powder

31. Emulsifiers  Stabilise mixtures of food components  Oil and water  Natural emulsifier - E322 lecithin  Synthetic  E 471Glyceryl monostearate  E442Ammonium phosphatide  E435polysorbate

32. Thickeners  Non-starch polysaccharides  Bind water to form gels  Algal origin  Alginates, agar, carrageenans  Plant origin  Guar gum, Locust Bean gum  Modified celluloses,  methyl cellulose  Bacterial origin  Xanthan gum

33. Is It Safe  Better than the alternative  Food degradation by biological or chemical action - very unsafe!