Tokyo, May 30 : Food and drink manufacturers in Japan are passing on costs to consumers under the pressure of higher raw material costs, with thousands of products subject to an average of a 12 per cent price hike, it was revealed on Monday. According to Credit research firm Teikoku Databank, of 105 major food and drink manufacturers polled in May, around 60 per cent of them have raised or plan to raise their prices this year, reports Xinhua news agency. The firm revealed that compared to a similar poll conducted in April, 2,000 more items will be affected by the price hikes, bringing the latest total to 8,385 items. Teikoku Databank said that price hikes will average an increase of 12 per cent, although processed foods including cup noodles, ham and frozen foods will be marked up by an average of 13 per cent due to higher prices for wheat and cooking oil. It also revealed that some companies have tried to make "stealth price hikes", which means keeping the prices the same for a particular food or beverage item, but surreptitiously reducing its quantity or volume. Such price hikes will become evident this summer, continue through fall, with no clear end in sight, the credit research firm said. /IANS