April 27 (Reuters) - Canada’s main stock index fell on Tuesday, dragged down by consumer staple companies, as markets were awaiting the U.S. Federal Reserve’s policy decision due later in the week. The U.S. central bank is expected to reaffirm its policy guidance after its two-day meeting ending on Wednesday. The policy statement and Fed Chief Jerome Powell’s news conference after the meeting are expected to shine some light on whether the employment landscape has changed. * At 9:42 a.m. ET (13:42 GMT), the Toronto Stock Exchange’s S&P/TSX composite index was down 24.61 points, or 0.13%, at 19,145.95. * Nine of the index’s 11 major sectors were lower, with consumer staples being the biggest loser. The materials sector , which includes precious and base metals miners and fertilizer companies, lost 0.4%. * In a bright spot, the energy sector climbed nearly 1% after oil prices rose to about $66 a barrel as OPEC+ sources said the producer group would stick to existing plans to boost oil output slightly from May 1. * Canada said on Monday it backed the use of Johnson & Johnson’s Janssen COVID-19 vaccine despite reports of rare blood clots, noting the issue had first been identified in doses made by AstraZeneca PLC. * On the TSX, 82 issues were higher, while 139 issues declined for a 1.70-to-1 ratio to the downside, with 12.78 million shares traded. * The largest percentage gainer on the TSX was real estate firm Firstservice Corp, which jumped 3%, after upbeat first-quarter results. ** First Quantum Minerals Ltd followed with a 2.7% gain after BMO raised its price target on the stock. * Plant-based food manufacturer Sunopta Inc fell 2.8%, the most on the TSX, while the second biggest decliner was advertising solutions provider AcuityAds Holdings, down 2.8%. * The most heavily traded shares by volume were Tetra Bio Pharma, Nevada Copper and Roxgold Inc . * The TSX posted 11 new 52-week highs and no new low. * Across all Canadian issues there were 45 new 52-week highs and two new lows, with total volume of 33.72 million shares. (Reporting by Devik Jain in Bengaluru; Editing by Amy Caren Daniel)