The germ who came to dinner (1978) Pt. 2 of 3

but most often we ourselves are at fault our skin is a microbes paradise warm humid with thousands of hiding places we always have bacteria living on us the electron microscope reveals an incredible landscape of planes crags and canyons so it's not surprising that if our hands touch anything with bacteria on it they will lodge in the cracks and fissures and be carried to anything else we touch all cuts and grazes even if they've almost healed will be a source of food poisoning bacteria so they should be disinfected and covered before anyone knew about bacteria they found that meat and fish would last if salted vinegar also kept food wholesome and anything cooked in plenty of sugar like jam could be stored for a long time without making you ill there was nothing wrong with well-dried fish or meat either if only you could chew it without knowing why people preserve food by exploiting the important weaknesses of bacteria there are only a limited set of conditions under which they do well if the environment is too sugary salty acid or dry they cannot survive but nowadays we usually control them with temperature keep food below 10 degrees centigrade and they cannot breed above 63 degrees centigrade and they die this is why catering regulations set these limits in the laboratory scientists try and create ideal conditions for bacteria they're cultured in these plastic containers on a kind of meat extract they flourish on these plates in any kitchen domestic or commercial all kinds of foods are prepared many of which will be just as good for growing bacteria some will already be contaminated a scientist infects his agar plate deliberately he dips a wire loop into a sample and streaks it across the surface a flame is used to keep out unwanted bacteria raw poultry will almost certainly be a carrier this means that anything touching it the knife board apron or hands will also be contaminated if the same hands unwashed are allowed to touch any other food they will pass on these bacteria this bowl of beef stock is not so very different from the culture medium the scientists used in the laboratory now comes the important part scientists plates are put in an incubator the temperature is quite warm about man's normal body temperature is ideal but a kitchen is often pretty warm too and if our stock hasn't been kept in a fridge these bacteria will also do very well by the next day the scientist has grown millions of them and so have we enormously magnified we can see the growth it usually won't be visible at all but each tiny dot is a colony of millions what happens now depends on whether the soup was reheated sufficiently to kill the bacteria good temperature control right up to serving is essential to make sure that your food is safe there are several food poisoning bacteria but salmonella clostridium and staphylococcus are the most commonly encountered if we know how to protect ourselves from these we will be safe from most of the others the story of salmonella may even start at the farm yard these animals look healthier now and so they are but if we have a constant supply of bacteria in our intestines so do they salmonella may even arrive at the farm in a bag of meal but it's at the slaughterhouse that the trouble really begins when the animals are killed any salmonella present in the excreta and intestines will infect the carcass they will still be there when the meat leaves for the butcher's shop this doesn't matter if the meat is kept correctly but it means that even with the cleanest of butchers one has to assume that all meat frozen or fresh carries food poisoning bacteria so you can see the quality is no safeguard even if the meat looks and smells good they're still likely to be there the butcher may do his best to keep his wares fresh and presentable but whether you buy meat for your family or restaurant it is now up to you to make sure that the bacteria are not given a chance to breed as soon as it arrives in the kitchen meat and poultry should go into the fridge freezer or cold store a good precaution is to store cooked food above rather than below raw meat where it cannot be dripped on the fridge is also the best place to de-freeze food it takes longer but while the meat gets warm enough to defrost it never gets warm enough to let bacteria grow a large bird like a turkey really does need proper de-freezing in cooking the heat takes a long time to penetrate the meat even in a fresh bird if the center is still frozen the heat will be wasted and melting the iced up portion and it will never become hot enough to kill the bacteria it is surprising how many people suffer each year for this reason we can also be a source of salmonella so hand washing after using the lavatory is an obvious precaution clostridium can survive for long periods in the water and soil and can easily be picked up by farm animals it is probably the second most important food poisoning agent and creates special problems of its own under certain conditions it will form spores these are little bodies that develop inside the cell a protective coat forms around these bodies which makes them incredibly hard to kill while heat will destroy the bacteria some of the spores will survive even thorough cooking for this reason it's just as important to store food properly after cooking as it is before clostridium will get onto meat in the same way as salmonella but favors food like mints rolled joints and stews given the chance the spores will germinate if the food is to be stored after cooking cool it quickly within an hour or two and then put it into a fringe