Among the sites hit was Quaker's Cedar Rapids plant which today remained closed with no indication of when it may reopen. Quaker is one of the four largest manufacturers of cold cereals with popular brands such as Cap'n Crunch and Life, as well the Quaker Oats and Quaker Rice Cakes. It also claims that two percent of its US brands hold the number-one or number-two position in their respective categories. A spokeswoman for the company said it was "too early to determine" what impact the flooding would have on production and supply. However, she confirmed that it was "a big site for Quaker" and they were looking for alternative ways to meet customer demand. Another company, Swiss Valley Farms, which produces dairy products including cottage cheese, yogurt and sour cream at Cedar Rapids was also evacuated last Wednesday. A spokeswoman for the company said: "There has been a definite impact. That plant does (produces) our entire business for cultured dairy products." She added that they had been able to fulfill customer orders as the company has other plants. The four-state cooperative, owned and controlled by 1,100 dairy producers, employs 700 people and has annual sales of $425 million. Penford Products' Cedar Rapids plant, where it produces starch and ethanol products, also had to be evacuated. However, the only product for food that is produced at this site is dextrose, which accounts for 5 percent of Penford Product's revenue. A spokesman for Penford said it was unable to estimate when it would reopen but added: "The company is notifying customers and will be actively working with them to minimize supply disruptions." Corn market Iowa is in the middle of the US corn belt and the National Corn Growers Association President Ron Litterer, has expressed concern about the impact of rainfall and flooding in the Midwest on the US corn crops. He added: "In Iowa in 1993, record rainfall reached well into the summer months and severely affected the crop that year. That is not the long-term forecast for 2008, and there's still a lot of the growing season left, so we are hopeful the final results will not be as devastating as it was 15 years ago. "While the U.S. Department of Agriculture has recently projected our third-largest crop ever at more than 11.7 billion bushels, we know that the final number depends on how the weather holds." Volatile markets have sent prices for corn and other commodities spiralling upwards in recent months. Recent bad weather has hit the production of agricultural commodities with severe droughts in Australia, as well as drought in Canada, Ukraine, the EU and US.