During a job interview, is it offensive to say that I haven't heard about the company? How can I say this in a polite and professional way?

if you are serious about the prospect and respect the company, you would do initial research (google it or ask someone who knows). After all, why would you work for a company you don't know anything about? If I were to be interviewed, I will make sure I understand the company culture. No one walks into a lions din blindly

According to my point of view, a candidate must always do research about the company also must have good knowledge about the company goals, vision and mission.These are the basic knowledge about the company.First impression is always a best impression.As a candidate he or she must have very good knowledge about the company and the responsibilities of the role which they are going to apply

My advice is to google the company before the interview or simply ask for the company profile when you are waiting for your turn. Its an important indication of why you are joining this specific company. Candidates shell be attracted for achievements rather than just a paying job.

In my opinion there is no polity way around this statement because you should not utter this statement under any circumstance.It purely portrays your disrespect for the organization no matter how big or small it is and shows your lack of interest and enthusiasm for the said role.

You are os uninterested in the role and the company that you did not even bother to do some research or prepare yourself for the interview.It might be clear sign of you just being in a desperate situation and looking for a quick fix you are appearing for all possible interview.on part of the job hunter it shows that there is no structure to his/her job hunt and he is not specific in his search.

Avoid saying it at all! Step 1, research on the company you will be going for an interview with. If time did not permit or employer provided short notice for interview, then the best way forward would be to confess saying that "Really sorry as I did not get time to learn about your company or products due to short notice provided". Do ask questions to let employer know that you are interest in knowing about their company. 

Yes, it shows a lack of seriousness and neglect on the part of the interviewee sine they are expected to research the company before even applying for their job however even when one researches there is always a learning curve regarding the company's structure, culture, work methods and even the job up for grabs so to get a soft landing and get more information as well i would answer that i have read some material about the company but it was rather too general so if you don't mind i would love for you to expound it more especially regarding my target department so that i can get a better feel about the work culture and judge how best i can fit.

Well, when preparing for an interview, it is important that you look at the website of the company(99.99% of the companies do have one). For those who do not have one, or whose operations are not clear from the website (you need to be careful of such companies), then its not offensive to ask about the company. If you are asked by the interviewer, have you heard about this company, or do you know anything about the company, then you can say 'I'm sorry Sir/Maam, but I have very limited informatioj about the company'

Yes it offensive. Its better to say " i havent had enough time to know much about the company but now as iam here iknowthat i will know much

The best way to deal with it would be doing some research about the company a day before going to the interview,

You can however say "I am impressed by your vision and would like to learn more about your organization, it is an industry that I am familiar with" 

If you get to an interview without preparation and research about the company, you are giving a very bad impretion. Always do research about the companies where you are being interviewed.Sometimes you won't find the information online directly, so you have to reach to some people who work in the company. you can find such people by searching for them using sites such as bayt or linkedin or sometimes facebook.

Thinking as a recruiter - the answer would depend on the level of the position I am interviewing for. For senior position I would expect you to know about the company; not so much for lower level positions.

So, honesty is then the best answer: "I do not have that much background about the company/My knowledge is limited to xxxx, but I am willing to learn."