Here is an example of source material being inaccurately summarized and a brief description of what the writer misunderstood. An accurate summary follows.
Original Source:
At slaughterhouses, on too-fast production lines, manure and the contents of stomachs and intestines often splatter the meat. In winter, about 1 percent of cattle from feedlots harbor E. coli; in summer, up to 50 percent can do so. "Even if you assume that only one percent is infected, that means three or four cattle bearing the microbe are eviscerated at a large slaughterhouse every hour, and a single animal infected with E. coli can contaminate 32,000 pounds of ground beef," Schlosser writes.
--Excerpted from Mindy Pennybacker, "Why Fast Food Costs Too Much"
Inaccurate Summary:
In her Green Guide article, "Why Fast Food Costs Too Much" Mindy Pennybacker states that one percent of the cattle slaughtered in a fast-paced, meat-processing plant on any given day carry the E. coli microbe and, as a result, 32,000 pounds of ground beef are contaminated in the eviscerating process every hour.
On the surface this summary appears to be accurate, however, it is not. As in most cases, inaccuracies are caused by omission or misinterpretation of facts.
In the first place, Pennybacker refers specifically to feedlot cattle in her article. This fact is important and must be included so that your readers understand the author's argument: pasture-fed and feedlot cattle carry widely differing risks in the slaughter and meat-packing process.
Secondly, the summary omits the fact that up to 50 percent of the cattle may carry the E. coli microbe during the summer months. It obscures the fact that the author deliberately chose the lower, one-percent figure as a baseline from which to draw a conclusion. The phrases "on any given day" and "every hour" are suggestive half-truths and completely inappropriate.
Lastly, the summary misstates the Eric Schlosser quote, which will lead the reader to a wrong conclusion. There is a world of difference between the words are and can. The summary states that 32,000 pounds of ground beef are contaminated every hour. In fact, in the original, Schlosser said "can contaminate", which only implies
Accurate Summary:
In her Green Guide article, "Why Fast Food Costs Too Much" Mindy Pennybacker states that one percent of feedlot cattle during the winter, and as much as 50 percent during the summer, carry the E. coli microbe from the feedlot to the slaughter house. Using Eric Schlosser's one percent baseline argument calculating three to four infected animals being slaughtered every hour, Pennybacker illustrates that 32,000 pounds of ground beef risk being contaminated every time one infected animal is eviscerated.