i) Cooking & Food Safety

• Many foods are best eaten soon after harvesting, without further preparation or cooking, e.g. many vegetables and fruits lettuce. Some exceptions e.g. potatoes, rhubarbs.
• Cooking food has important functions such as promoting safety and quality of foods by killing moulds, yeasts and bacteria that are pathogenic and cause spoilage.

• Cooking of food may be described as both an art and a science.
• Cooking has many cultural and religious aspects.
• Cooking of food invariably involves the use of an intermediate medium such as water, steam, air or oil. In the home, the kitchen contains the most germs (not the bathroom as many might think). Bacteria that cause illnesses such as food poisoning, e.g. E. coli and salmonella, enter the home in the kitchen from foods, our hands and through pets. It is important to therefore to ensure that the good standards of hygiene are maintained in the home:

• Washing hands thoroughly with soap and warm water before cooking, after covering one’s mouth after sneezing/ coughing, going to the toilet, after touching raw food, touching bins.
• Regularly cleaning surfaces and utensils helps to remove bacteria from raw meat.
  Reducing contamination in this way extends to keeping separate chopping boards from different food types, e.g. one for meats and one for fruit/ vegetables.Cleaning tools such as clothes and sponges are breeding grounds for bacteria so should replaced regularly.

• Cooking food at the right temperature makes certain that harmful bacteria are killed: food must be piping hot (steam visible) throughout before it is consumed. The following foods need to be cooked thoroughly before eating (so that, in most cases, the meat is no longer pink and the juices run clear): pork, kebabs, sausages, poultry, offal ( including liver), joints of meat, burgers.- Searing food, whereby the outside of the meat is sealed (cooked at a high temperature) helps to kill microbes on the surface. This is a useful method for preparing some foods that may be consumed after they been less thoroughly cooked, such as rare steaks. - Cooked food must be cooled at room temperature before it is refrigerated, ideally within 90 minutes. Food placed in the in the fridge soon after cooking results in uneven cooling and resilient bacteria can survive and thrive.
• Washing fruit and vegetables under cold running water before consumption is a simple means to remove dirt and many germs that may be on the surface.

ii) Boiling

• Common method of moist heat cooking
• Solvent action of boiling leads to a significant disadvantage of food cooked losing its some of its soluble matter, such as specific nutrients, e.g. thiamine and ascorbic acid in particular.
• Volume of water, cooking time and size of vegetable makes an impact on nutrient loss: the less volume of water used, the less amount time used and the larger the vegetable used the less the nutrient loss.

iii) Frying

• Common method of cooking, cheap and highly available
• Copper is a source of contamination of cooking oil – minute quantities can make oil rancid, therefore use copper free cooking pans.
• Frying dehydrates foods, giving it its characteristic crispy and attractive flavour.
• Frying effectively adds fat to the food cooking, e.g. raw potato has a negligible quantity of fat (0.2g fat per 100g), however fried potatoes has 7-15g fat per 100g.
• Shallow frying is less deleterious than deep frying: less fat is added to the foodstuff.

iv) Baking

• Dry heat is employed to cook the food gradually – heat travels from the surface of the foodstuff to the centre.
• High temperature involved result in the loss of nutrients that are greater than losses in boiling foods.
• Amino acids structural change via baking results in several amino acids becoming resistant to enzymatic breakdown in the gut.

v) Microwave

• Unlike other conventional forms of cooking foods, microwave cooking cooks food from the inside out.
• This confers the main advantage of using microwave cooking – dramatically reducing the cooking time of food.
• Used extensively in canteen, restaurants and hospitals to avoid having foods kept under/ on heat source and quickly re-heat foods.
• In theory, because of short cooking time, nutrient loss of foods is comparable to other forms of cooking.