Exhibit 99.1

FOR IMMEDIATE RELEASE

SUNOPTA ANNOUNCES FIRST QUARTER 2011 RESULTS

Toronto, Ontario, May 11, 2011 - SunOpta Inc. (“SunOpta” or “the Company”) (NASDAQ:STKL; TSX:SOY), a leading global company focused on natural, organic and specialty foods, today announced financial results for the quarter ended April 2, 2011. All amounts are expressed in U.S. dollars and results are reported in accordance with U.S. GAAP, except where specifically noted.

The Company realized revenues of $260.9 million in the first quarter of 2011 versus revenues of $216.7 million in the first quarter of 2010, a year over year increase of 20.4% . Revenues increased 9.7% excluding the impact of the acquisitions completed late in 2010.

For the first quarter of 2011, the Company realized operating income¹ of $11.0 million or 4.2% of revenues, an increase of approximately 14.6%, versus operating income¹ in the first quarter of 2010 of $9.6 million or 4.4% of revenues. The increase in operating income was driven by increases in the Grains and Foods Group, International Foods Group and Opta Minerals Inc. combined with reduced corporate spending. Excluding the year over year impact of the foreign exchange loss (gain), operating earnings increased 31.3% .

For the first quarter of 2011, the Company reported earnings per diluted common share from continuing operations of $0.08 or $5.1 million, as compared to $0.06 or $4.2 million for the first quarter of 2010. The Company realized EBITDA¹ in first quarter of 2011 of $15.9 million as compared to $14.0 million in the first quarter of 2010, an increase of approximately 13.7% .

At April 2, 2011, the Company’s balance sheet reflects a current working capital ratio of 1.39 to 1.00, long-term debt to equity ratio of 0.22 to 1.00 and total debt to equity ratio of 0.62 to 1.00. During the first quarter of 2011 the Company used cash from continuing operating activities of $33.9 million as compared to $13.6 million in the first quarter of 2010, reflecting the impact of increased commodity volumes and costs and increased inventory and accounts receivable balances related to growth in the business. At April 2, 2011 the Company has total assets of $657.4 million and a net book value of $4.56 per outstanding share. At quarter-end, the Company was in compliance with its bank financial covenants.

Steve Bromley, President and Chief Executive Officer of SunOpta commented, ”We are pleased with our first quarter 2011 results which represent record first quarter net earnings for our Company. Operating income¹ has improved in spite of rising commodity prices. We continue to streamline our portfolio and over the last twelve months have divested of three non-core operations, most recently the Mexican Frozen Fruit Assets, while over the same period acquiring two core operations. We remain focused on growing our business in fast growing healthy foods categories while at the same time improving operating margins and returns on assets employed. We believe we are well positioned to continue our profitable growth in the future.”

The Company plans to host a conference call at 10:00 AM Eastern Time on Thursday, May 12, 2011 to discuss the first quarter results and recent corporate developments. The conference call can be accessed via a link at the Company’s website at www.sunopta.com. Additionally, the call may be accessed with the toll free dial-in number 1-877-312-9198 or 631-291-4622. A replay number can also be accessed between May 12^th and 19^th with the toll free dial-in number 1–800-642-1687 or 706-645-9291 followed by pass code: 62090916#.

¹See discussion of non-GAAP measures

About SunOpta Inc.

Certain statements included in this press release may be considered “forward-looking statements” within the meaning of the United States Private Securities Litigation Reform Act of 1995 and applicable Canadian securities legislation, which are based on information available to us on the date of this release. These forward-looking statements include, but are not limited to, our continued efforts to streamline our portfolio, our focus on growing our business and improving operating margins and returns on assets employed and our positioning to continue profitable growth in the future. The terms and phrases “continue”, “improving”, “remain focused”, “positioned”, and other similar terms and phrases are intended to identify these forward looking statements. Forward looking statements are based on information available to us on the date of this release and are based on estimates and assumptions made by the Company in light of its experience and its perception of historical trends, current conditions and expected future developments as well as other factors the Company believes are appropriate in the circumstances including, but not limited to, general economic conditions, consumer interest in health and wellness, product pricing levels, current customer demand, competitive intensity, cost rationalization and product development initiatives. Whether actual timing and results will agree with expectations and predications of the Company is subject to many risks and uncertainties including, but not limited to, global economic conditions, consumer spending patterns and changes in market trends, decreases in customer demand, potential failure of product development, working capital management and continuous improvement initiatives, availability and pricing of raw materials and supplies, and other risks described from time to time under “Risk Factors” in the Company’s Annual Report on Form 10-K and its Quarterly Reports on Form 10-Q (available at www.sec.gov). Consequently all forward-looking statements made herein are qualified by these cautionary statements and there can be no assurance that the actual results or developments anticipated by the Company will be realized.

For further information, please contact:

SunOpta Inc.

Steve Bromley, President & CEO
Eric Davis, Vice President & CFO
Tony Tavares, Vice President & COO
Susan Wiekenkamp, Information Officer
Tel: 905-455-2528, ext 103
susan.wiekenkamp@sunopta.com
Website: www.sunopta.com

SunOpta Inc.
Consolidated Statements of Operations
For the quarters ended April 2, 2011 and April 3, 2010
(Expressed in thousands of U.S. dollars, except per share amounts)
(Unaudited)

SunOpta Inc.
Consolidated Balance Sheets
As at April 2, 2011 and January 1, 2011
Unaudited
(Expressed in thousands of U.S. dollars, except per share amounts)

SunOpta Inc.
Consolidated Statements of Cash Flow
For the quarters ended April 2, 2011 and April 3, 2010
(Expressed in thousands of U.S. dollars)
(Unaudited)

SunOpta Inc.
Segmented Information
For the quarters ended April 2, 2011 and April 3, 2010
(Expressed in thousands of U.S. dollars)
(Unaudited)

The SunOpta Foods has the following segmented reporting:

The SunOpta Foods has the following segmented reporting:

(Segment Operating Income is defined as “Earnings from continuing operations before the following” excluding the impact of “other expense, net”)

¹Non-GAAP Measures

In addition to reporting financial results in accordance with generally accepted accounting principles (“GAAP”), the Company provides information regarding Operating Income and Earnings before interest, taxes, depreciation and amortization (“EBITDA”) as additional information about its operating results, which are not measures in accordance with GAAP. The Company believes that these non-GAAP measures assist investors in comparing performance across reporting periods on a consistent basis by excluding items that are not indicative of the Company’s core operating performance. The non-GAAP measures of operating income and EBITDA should not be considered in isolation or as a substitute for performance measures calculated in accordance with GAAP.

The Company defines Operating Income as “Earnings from continuing operations before the following” excluding the impact of “Other expense, net”; and EBITDA as Operating Income plus depreciation and amortization. The following is a tabular presentation of Operating income and EBITDA, including a reconciliation to GAAP earnings, which the Company believes to be the most directly comparable GAAP financial measure.