【四级】The overall number of bacteria on the surface mattered more, and this decreased over time after the initial introduction.
【高考】Consequently, she succeeded in making a kind of candy only using natural sweeteners, which can reduce oral bacteria.
【六级】It's not only the study of human population, but the populations of non-human species, including viruses like influenza, the bacteria in your gut, plants that you eat, animals that you enjoy or that provide you with meat.
【四级】Clarke and her colleagues introduced bacteria to floor tiles (瓷砖) and then placed cookies on the tiles for varying times.
【六级】When this water is used for agricultural irrigation, farmers risk absorbing disease-causing bacteria, as do consumers who eat the produce raw and unwashed.
【四级】Bacteria are carried by various 'media', which can include raw food, moist surfaces where bacteria have been left, our hands or skin and from coughing or sneezing (打喷嚏).
【高考】Bacteria are an annoying problem for astronauts.
【高考】For the past two years, Gordon's students have been studying ways to kill bacteria in zero gravity, and they think they're close to a solution.
【四级】five minutes after that, we placed either bacon or bread on the surface for 5, 30 or 60 seconds,and then measured the number of bacteria transferred to the food.
【四级】These microscopic layers of deposits containing bacteria are known as biofilms and they are found on most surfaces and objects.
【四级】To find out, we introduced bacteria to squares of tile, carpet or wood.
【四级】We found that the number of bacteria transferred to either kind of food didn't depend much on how long the food was in contact with the contaminated surface——whether for a few seconds or for a whole minute.
【四级】Also, certain types of bacteria are extremely harmful, and it takes only a small number to make you sick.
【四级】Hands, foods and utensils can carry individual bacteria living in communities contained within a protective film.
【四级】We wanted to know if the length of time food is in contact with a contaminated surface affected the rate of transfer of bacteria to the food.
【四级】For example, 10 bacteria or less of an especially deadly strain of bacteria can cause severe illness and death in people with compromised immune systems.
【四级】When a carpet was contaminated, less than 1% of the bacteria were transferred.
【高考】Ordinary soap, use correctly, can deal with bacteria effectively.
【四级】But when the food was in contact with tile or wood, 48-70% of bacteria were.
【六级】In fact, you may have heard about the new "superbugs", which are antibiotic-resistant bacteria that have developed as a result of overprescribed antibiotics.