THE CHEMICAL BASES OF REDDENING

Salting is a very old method of preserving easily perishable foods. Me at as well has been preserved with common salt for a very long time. T he oldest reference of the simultaneous use of nitrate dates from the year 1835. In the ''Farmers' Register'' it is recommended that salpetr e should be used when manufacturing bacon in order to improve the juic iness and aroma of the product. The beginning of a better understandin g of the processes that take place when this substance is used was sig nalled by microbiological investigations in which POLENSKE (1891) was able to show that certain bacteria reduce nitrate to nitrite. As LEHMA NN (1899) and KISSKAT (1899) have shown, it is this nitrite and not eh t nitrate which is the actual agent and its metabolic products also re act with myoglobin to produce the cured colour. HALDANE (1901) attribu ted the production of the cured red colour to the formation of a compo und from nitric oxide and haemoglobin (!). The present paper considers the complicated chemical processes which take place during reddening.