Someone plugging electronic gadgets such as an iPod or digital picture frame into the computer runs the risk of picking up a pre-installed virus, according to industry consultants.

Experts believe the problem stems from lax quality control, often in Chinese factories that are trying to keep costs low, through workers who plug an infected device into a factory computer used for testing.

Recent cases reviewed by the Associated Press include some of the most widely used tech devices: Apple iPods, digital picture frames sold by Target and Best Buy stores and TomTom navigation gear.

The companies whose products were found to be infected in these cases refused to reveal details about the incidents. Of those that confirmed factory infections, all said they had corrected the problems and taken steps to prevent recurrences.

Jerry Askew, a Los Angeles computer consultant, bought a new Uniek digital picture frame to surprise his 81-year-old mother for her birthday. But when he added family photos, it tried to unload a few surprises of its own.

When he plugged the frame into his Windows PC, his antivirus program alerted him to a threat. The $50 frame, built in China and bought at Target, was infested with four viruses, including one that steals passwords.

Protection from antivirus program

Security experts say the malicious software is apparently being loaded at the final stage of production, when gadgets are pulled from the assembly line and plugged into a computer to make sure everything works.

If the testing computer is infected — say, by a worker who used it to charge his own infected iPod — the digital germ can spread to anything else that gets plugged in.

Consumers can protect themselves from most factory-loaded infections by running an antivirus program and keeping it up to date.

Apple said a virus that infected a small number of video iPods in 2006 came from a PC used to test compatibility with the gadget's software.

Best Buy, the biggest consumer electronics outlet in the U.S., said it pulled its affected China-made digital frames from the shelves and took "corrective action" against its vendor. But the company declined repeated requests by the Associated Press to provide details.

Sam's Club and Target said they are investigating complaints but have not been able to verify that their frames were contaminated.

With files from the Associated Press