Apple has sacked hundreds of contractors after it suspended the 'grading' program earlier this month. At least 300 people at Apple's European headquarters in Cork, Ireland was asked to leave according to the reports in the Guardian. 

As per the reports, Apple told the contracting firms that it's ending their grading work. The workers were asked to leave in as little as one week's notice.

The contractors had the job of listening to and grading recordings by Apple’s digital assistant Siri. The worker mentioned that the small print of every Siri consumer have been stored nameless.

Apple put the program on hold after the Guardian newspaper reported that contractors working on Apple's behalf regularly heard confidential information, drug deals and couples having sex.

Increased public and political scrutiny of data privacy practices have forced greater transparency from Silicon Valley companies, with Alphabet Inc's Google pausing reviews of audio recordings from its Google assistant service for all purposes in all languages after a leak of Dutch audio data.

Apple has promoted its privacy practices in an effort to distance itself from its rivals and has taken steps since Siri's introduction in 2011 to limit data collection. Audio recordings are deleted after a set period of time, users were identified by a random number, and data such as a user's unread messages or calendar appointments were not sent to Apple's servers.

But Apple tapped humans to improve the service, a process that the company's researchers have in the past told Reuters.

Apple says the number of audio recordings reviewed was small - less than 0.2% of total requests - but users had no way to opt-out of having audio retained and reviewed by humans except turning Siri off altogether.

Apple on Wednesday said that it will quit keeping audio for human review and instead let users opt into having their audio reviewed if they choose. The company said it will still use computer-generated transcripts to improve Siri.