Question

1. first, they covered three different floor surfaces with salmonella bacteria, which is often found on raw chicken, is a major cause of food poisoning. after coating the floors in salmonella, they dropped bologna sandwiches on these contaminated surfaces. finally, they measured the amount of bacteria on the food.

the scientists discovered that food that had been on the floor for just five seconds could have up to 8,000 bacteria on it. food that was left for one minute had ten times that amount—up to 80,000 bacteria. because you can get food poisoning from as few as ten salmonella bacteria, even a small amount of salmonella can be dangerous. this means that the five - second rule is simply not true.
in addition to amount of time food has spent on the floor, the location of the floor itself also plays an important part in how many bacteria may be transferred to your food. surprisingly, many outdoor locations are actually cleaner than some places inside your house. according to dr. harley rotbart, a professor at the university of colorado school of medicine, the sidewalk is likely to be cleaner than your kitchen floor. rotbart argues that the germs from raw meats that are probably in your kitchen are far more dangerous than the bacteria typically found on pavement. unsurprisingly enough, the bathroom floor is also likely to have more dangerous bacteria on it than the sidewalk.
the type of food you have dropped can also affect the number of bacteria on the food. foods that are high in salt or sugar but low in water content—like cookies or crackers—grow fewer bacteria on them after they have come into contact with the floor. food with a higher water content, such as cooked pasta or sliced fruit, pick up a larger quantity of bacteria.
so what does this mean for your dropped chocolate chip cookie? if you dropped it outside on the sidewalk, the five - second rule might keep you safe. however, if you dipped it in milk first and then dropped it in your kitchen or bathroom, you should probably follow a zero - second rule instead. no matter how delicious that cookie is, it is not worth a trip to the
challenge question
if added to the passage, which of the following facts would fit best in paragraph 4?
a there are as many as 25,000 germs on every square inch of a cell phone.
b the dirtiest spot on your kitchen floor is right in front of the sink. this area can contain over 800 bacteria per square inch.
c most people infected with salmonella develop diarrhea, fever, and stomach cramps 12 to 72 hours after coming into contact with the bacteria.
d sticky foods like iced pastries or gummy candies collect far more bacteria than foods with smooth surfaces, like unpeeled fruits or hard candies.

Explanation:

Paragraph 4 (the highlighted text) discusses how the location of the floor affects bacteria transfer, including outdoor vs. indoor cleanliness and food type impact. Option B talks about a dirty kitchen floor area, which relates to floor location and bacteria, fitting the paragraph's focus on floor location and bacteria levels. Option A is about cell phones (unrelated to floor), C is about Salmonella symptoms (not floor location/bacteria transfer), D is about food types collecting bacteria (not floor location as in the paragraph). So B is the best fit.

Answer:

B. The dirtiest spot on your kitchen floor is right in front of the sink: this area can contain over 800 bacteria per square inch.