<PAGE>

                                                                   EXHIBIT 31

                                  CERTIFICATION


I, Dennis C. Zensen, Chairman of the Board, President and Chief Executive
Officer, certify that:

     1.   I have reviewed this amended annual report on Form 10-K/A of Sylvan
          Inc.;

     2.   Based on my knowledge, this amended annual report does not contain any
          untrue statement of a material fact or omit to state a material fact
          necessary to make the statements made, in light of the circumstances
          under which such statements were made, not misleading with respect to
          the period covered by this report;

     3.   Based on my knowledge, the financial statements, and other financial
          information included in this amended annual report, fairly present in
          all material respects the financial condition, results of operations
          and cash flows of the registrant as of, and for, the periods presented
          in this report;

     4.   The registrant's other certifying officer and I are responsible for
          establishing and maintaining disclosure controls and procedures (as
          defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal
          control over financial reporting (as defined in Exchange Act Rules
          13a-15(f) and 15d-15(f)) for the registrant and have:


          a)   Designed such disclosure controls and procedures, or caused such
               disclosure controls and procedures to be designed under our
               supervision, to ensure that material information relating to the
               registrant, including its consolidated subsidiaries, is made
               known to us by others within those entities, particularly during
               the period in which this amended annual report is being prepared;


          b)   Evaluated the effectiveness of the registrant's disclosure
               controls and procedures and presented in this amended annual
               report our conclusions about the effectiveness of the disclosure
               controls and procedures as of the end of the period covered by
               this report, based on such evaluations; and


          c)   Disclosed in this amended annual report any change in the
               registrant's internal control over financial reporting that
               occurred during the registrant's most recent fiscal quarter (the
               registrant's fourth fiscal quarter in the case of an annual
               report) that has materially affected, or is reasonably likely to
               materially affect, the registrant's internal control over
               financial reporting; and


     5.   The registrant's other certifying officer and I have disclosed, based
          on our most recent evaluation of internal control over financial
          reporting, to the registrant's auditors and the audit committee of the
          registrant's board of directors:


          a)   All significant deficiencies and material weaknesses
               in the design or operation of internal control over financial
               reporting which are reasonably likely to adversely affect the
               registrant's ability to record, process, summarize and report
               financial information; and


          b)   Any fraud, whether or not material, that involves management
               or other employees who have a significant role in the
               registrant's internal control over financial reporting.



April 23, 2004                                /s/  DENNIS C. ZENSEN
                                              -------------------------
                                              Chairman of the Board, President
                                              and Chief Executive Officer
                                              (Principal Executive Officer)



<PAGE>


                                                                    EXHIBIT 31

                                  CERTIFICATION

I, Donald A. Smith, Chief Financial Officer, certify that:


     1.   I have reviewed this amended annual report on Form 10-K/A of Sylvan
          Inc.;


     2.   Based on my knowledge, this amended annual report does not contain any
          untrue statement of a material fact or omit to state a material fact
          necessary to make the statements made, in light of the circumstances
          under which such statements were made, not misleading with respect to
          the period covered by this report;


     3.   Based on my knowledge, the financial statements, and other financial
          information included in this amended annual report, fairly present in
          all material respects the financial condition, results of operations
          and cash flows of the registrant as of, and for, the periods presented
          in this report;


     4.   The registrant's other certifying officer and I are responsible for
          establishing and maintaining disclosure controls and procedures (as
          defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal
          control over financial reporting (as defined in Exchange Act Rules
          13a-15(f) and 15d-15(f)) for the registrant and have:


          a)   Designed such disclosure controls and procedures, or caused such
               disclosure controls and procedures to be designed under our
               supervision, to ensure that material information relating to the
               registrant, including its consolidated subsidiaries, is made
               known to us by others within those entities, particularly during
               the period in which this amended annual report is being prepared;


          b)   Evaluated the effectiveness of the registrant's disclosure
               controls and procedures and presented in this amended annual
               report our conclusions about the effectiveness of the disclosure
               controls and procedures as of the end of the period covered by
               this report, based on such evaluations; and


          c)   Disclosed in this amended annual report any change in the
               registrant's internal control over financial reporting that
               occurred during the registrant's most recent fiscal quarter (the
               registrant's fourth fiscal quarter in the case of an annual
               report) that has materially affected, or is reasonably likely to
               materially affect, the registrant's internal control over
               financial reporting; and


     5.   The registrant's other certifying officer and I have disclosed, based
          on our most recent evaluation of internal control over financial
          reporting, to the registrant's auditors and the audit committee of the
          registrant's board of directors:



          a)   All significant deficiencies and material weaknesses in the
               design or operation of internal control over financial reporting
               which are reasonably likely to adversely affect the registrant's
               ability to record, process, summarize and report financial
               information; and


          b)   Any fraud, whether or not material, that involves management or
               other employees who have a significant role in the registrant's
               internal control over financial reporting.



April 23, 2004                                    /s/  DONALD A. SMITH
                                                  ----------------------------
                                                  Chief Financial Officer
                                                  (Principal Financial Officer)