Food Science :Food Science


Micro-organisms – Used in Bread :Micro-organisms – Used in Bread Yeast break down glucose without oxygen. This is called FERMENTATION. GLUCOSE ? ALCOHOL + CARBON DIOXIDE The carbon dioxide made in fermentation is used to make the bread rise. The alcohol evaporates in the oven –so you don’t get drunk YEAST


Micro-organisms – Yeast used in beer making :Micro-organisms – Yeast used in beer making Barley grains are soaked in water, and then crushed and filtered to form a sugary liquid. The sugary liquid is boiled with HOPS to give a bitter flavour. Yeast is then added to the mixture, fermentation occurs and the alcohol is made.


Micro-organisms – Yeast :Micro-organisms – Yeast Grapes are crushed. Enzymes in the yeast convert the sugar in the yeast into ethanol. Wine is left in barrels for a few months to mature.


Micro-organisms – Bacteria and Moulds (CHEESE) :Micro-organisms – Bacteria and Moulds (CHEESE) Milk is heated then cooled. A Mould (type of fungus) can be added for flavour. A starter culture of bacteria is added. Rennet which contains enzymes is stirred into the milk which forms a CURD. The liquid part is drained of to leave the CURD. Salt is added to the curd to make the CHEESE which is shaped and left to ripen


Micro-organisms – Bacteria (YOGHURT) :Micro-organisms – Bacteria (YOGHURT) A starter culture of bacteria is added to milk. It is warmed to 400C Enzymes in the bacteria change the lactose in the milk to lactic acid. The acid makes the milk clot and solidify to form yogurt


FOOD SAFETY :FOOD SAFETY Food poisoning is caused by the growth of micro-organisms usually bacteria.


Food Poisoning :Food Poisoning Bacteria that cause food poisoning are; CAMPYLOBACTER E.COLI SALMONELLS


OPTIMUM CONDITIONS FOR BACTERIAL GROWTH :OPTIMUM CONDITIONS FOR BACTERIAL GROWTH WARMTH MOISTURE FOOD SOURCE


SYMPTOMS OF FOOD POISONING :SYMPTOMS OF FOOD POISONING STOMACH PAINS VOMITING DIARRHOEA


HOW FOOD PREPARATION AREAS ARE KEPT FREE OF BACTERIA :HOW FOOD PREPARATION AREAS ARE KEPT FREE OF BACTERIA PERSONAL HYGIENCE DISINFECTANTS DETERGENTS STERILSATION DISPOSAL OF WASTE PEST CONTROL (MICE, INSECTS….)


WAYS IN WHICH THE GROWTH OF BACTERIA IS SLOWED DOWN OR STOPPED :WAYS IN WHICH THE GROWTH OF BACTERIA IS SLOWED DOWN OR STOPPED REFRIGERATION FREEZING HEATING DRYING SALTING PICKLING


TESTS TO FIND OUT THE LEVEL OF BACTERIA IN FOOD – SERIAL DILUTION METHOD :TESTS TO FIND OUT THE LEVEL OF BACTERIA IN FOOD – SERIAL DILUTION METHOD 3. NUMBER OF BACTERIA =NUMBER OF COLONIES x DILUTION SAMPLE 1. SERIAL DILUTION 2. Put 1ml from each tube into Petri dish and incubate for a few days. The count the number of colonies if possible in each dish.


ASEPTIC TECHNIQUE TO SWAB AREAS TO DETECT THE PRESENCE OF BACTERIA :ASEPTIC TECHNIQUE TO SWAB AREAS TO DETECT THE PRESENCE OF BACTERIA A STERILE COTTON SWAB IS USED TO SAMPLE THE SURFACE BY RUBBING THE SWAB ON THE SURFACE, THEN LIGHTLY ON THE SURFACE OF A AGAR PLATE AGAR PLATE


MAKE STREAK PLATES :MAKE STREAK PLATES Dip a sterilised wire loop into a sample of bacteria. Make 4 or 5 streaks across one edge of a agar plate. Flame the loop to sterilise it. Make a second series of streaks by crossing over the first set. Repeat steps 3 and 4 make a third and fourth set of streaks Incubate the plate upside down allowing the cells to form colonies


Farming :Farming As crops grow they remove essential nutrients from the soil and these need to be replace. Plants need the minerals NITRATES, PHOSPHATES, POTASSIUM AND MAGNESIUM which they obtain from the soil for healthy growth.


Intensive and Organic Farming :Intensive and Organic Farming


Intensive V Organic :Intensive V Organic Produces large quantities of food cheaply and efficiently by maximising the growth of crops and farm animals Some customers are willing to pay more for a product that has been produced in a more environmentally friendly way.


Intensive V Organic :Intensive V Organic Increases crop yields by using artificial fertilizers, pesticides, herbicides and fungicides. Increases meat production by using controlled environments (hens and pigs. Did you watch ‘chicken run’? Uses Natural fertilizers, natural pesticides and mechanical methods to remove weeds in crop production. Keeps animals under more natural conditions.


Plan and assess how well a plant grows under various conditions. :Plan and assess how well a plant grows under various conditions. Read up on this in your revision books. You may be asked to draw equipment, write a plan, explain the results and predict the results. Remember the germinating seeds we set up.