BEIJING — Athletes who eat at the brand-new Olympic Village in Beijing are getting an ironclad assurance that the food will be safe, but they’re on their own if they choose to eat elsewhere in the city, Chinese officials told reporters yesterday.

A spokeswoman for the Beijing Food Safety Administration, Tang Yanhua, said an elaborate system of tracing and testing would ensure that food to be served to about 16,000 athletes, coaches, and officials at the Olympic Village is “perfectly safe.”

“All of the items on the menu can be traced back to its raw materials,” Ms. Tang told reporters at a news conference.

“From where it’s from at the farm to when it’s presented on the table, we’ll have safe and complete information and are fully convinced they are safe to consume.”

However, an official with the Beijing Olympic Committee, Kang Yi, said they were relying on athletes to look out for themselves when eating outside the village.

“Before the competition starts, I think for all the foreign athletes, they will exercise voluntary control of their food consumption,” Ms. Kang said, citing a survey of the practices of elite Chinese athletes.

“They will not consume those foods they are not familiar with. … That is because they’re not sure whether they’re allergic to the food or whether the foods will lead to any other unexpected problems. Therefore, we do not need to exercise any control on their food consumption. They will do it by themselves.”

Ms. Kang said she had no particular worry that athletes who have already competed might become more adventurous in their eating choices and become sick. “It is their freedom to eat wherever they want,” she said.

One of the unusual food-safety measures being used at the Olympic Village involves preserving some of every dish served. “We will have a sample of each item on the menu and keep the sample for at least 48 hours. Should the athletes fall ill because of the food consumption, we will run a testing,” Ms. Kang said.

The officials dodged a question from a Chinese reporter about whether the new surveillance system had detected any substandard or contaminated products destined for the Games.

The measures will have little impact on American athletes. They’re not staying at the Olympic Village, but at a training center set up at a university several miles away. The American team has imported much of the food to be served there.

American officials reportedly found high levels of hormones in meat purchased in the commercial market in China last year, but Ms. Tang insisted that Chinese officials have used the impetus of the Olympics to improve the overall quality of food.

“We have successfully raised our food security level in Beijing to a new high,” Ms. Tang said.