Canning and Fish Packaging Technology

Unit 5 - Changes in canned foods and spoilage

5.1.2.Changes during storage of processed cans
Due to exchange of various components of food, it becomes balanced with respect to taste and flavour. This may take place in three months for certain foods and in some others it may take even six months (e.g. acidity, saltiness, sugar) resulting in maturation of can.
All the changes happening during heat processing also happens during storage even though at a slow rate.
During long storage period, the vacuum inside the can reduces and composition of head space gases change. Oxygen content reduces within a short time, hydrogen content increase in acid foods, carbon dioxide also increases and in some foods ammonia and other gases may be produced.
In addition to these changes, loss of colour and flavour, softening of solids, fat oxidation, rancidity and subsequent browning, loss of clarity of brine etc occur during long term storage of canned foods. However, in spite of these changes, not much of change in nutritive value takes place and food remains good without spoilage.