Food and nutrition.pdf

250 Chutneys, Pickles, Salted Vegetables and SaucesSmall Scale Peeler for FruitsCanning is not suitable for small scale processing for the followingreasons: the time and temperature of canning are critically important andmust be carefully controlled. If the cans are under-processed, there is arisk of serious food poisoning and even death from a type of microorganismnamed Clostridium botulinum. If cans are over-processed, thevegetables lose much of their texture, colour, vitamins and flavour andare not saleable. The establishment of correct heating conditions dependson the type of food, the size and shape of the can and the initial level ofcontamination of the vegetables. This requires the skills of a qualified foodtechnologist or microbiologist.When foods are heated in sealed cans during the canning process,the temperature of sterilization is above 100°C and the pressure outsidethe can must equal that inside, to prevent the cans from exploding. Thisis achieved using high pressure steam and a strong vessel named a'retort'.Both steam boiler and retort are expensive and likely to be beyond themeans of a small scale processor. Additionally, compressed air is neededto maintain the pressure while cans are being cooled, which together withthe necessary controllers, adds to the capital cost of equipment.Even if cans are available in a particular country, they are usuallymore expensive than other forms of packaging. Different types of productalso require a particular internal lacquer to prevent the metal fromcorroding when it is in contact with the fruits or vegetables and suchlacquers may not always be available. In addition a 'seamer' is needed toseal the lid onto the can and regular checks and maintenance are necessaryto ensure that the seam is properly forined. Failures in seams are one ofthe main causes of spoiled or dangerous canned foods.It is therefore necessary to ensure that seamer operators are fullytrained and experienced in adjusting the machines and a 'seammicrometer' is another necessary capital expense to be able to do this. In