<PAGE>   1

   

                                                                    EXHIBIT 10.7


                         AMENDMENT TO LETTER OF INTENT

     With reference to the Letter of Intent dated April 27, 1998, by and between
BIOGENESIS ENTERPRISES, INC. and SUMMIT TECHNOLOGIES, INC., the parties hereto
do mutually agree to the following amendment to said original Letter of Intent:

         1.    TRANSFER:  BioGenesis hereby conveys and transfers unto Summit
               the Patent Rights and Intellectual Property described in the
               Letter of Intent.

         2.    PAYMENT:  Summit has met the requirements stipulated in the
               Payment section Parts A and B of paragraph 3 of the original
               Letter of Intent.

         Part C of paragraph 3, the Balance shall be amended as follows:

               A.    $200,000 to be paid on or before February 1, 1999;

               B.    $300,000 to be paid on or before April 1, 1999;

               C.    $300,000 to be paid on or before August 1, 1999;

               D.    The Common Stock shall be delivered to BioGenesis on or
                     before the first business day after the payment of the
                     February 1, 1999 payment.

     This Amendment and the original Letter of Intent supersede the exclusive
licensing agreement between the parties hereto.

     All other aspects of the original Letter of Intent dated April 27, 1998,
shall remain in effect.

     IN WITNESS WHEREOF, the parties have executed this Amendment to Letter of
Intent as of the date contained herein.



                                           BIOGENESIS ENTERPRISES, INC.
                                                                                
                                                By: /s/ MOHSEN C. AMIRAN
                                                    ----------------------------
                                                    Mohsen C. Amiran, President
                                                                                
                                                Date: November 2, 1998




                                           SUMMIT TECHNOLOGIES
                                                                                
                                                By: /s/ B. KEITH PARKER
                                                    ---------------------------
                                                    B. Keith Parker, CEO
                                                                                
                                                Date: November 2, 1998




                                                                    Exhibit 10.7
                                                               Page 1 of 4 Pages

    


<PAGE>   2
   

                                LETTER OF INTENT


     Letter of Intent dated this 27th day of April, 1998, by and between
BIOGENESIS ENTERPRISES, INC., an Illinois corporation with an office at 330
South Mt. Prospect Road, Des Plaines, Illinois 60016, and SUMMIT TECHNOLOGIES,
INC., a Texas corporation with an office at 414 East Loop 281, Longview, Texas
75605.

                                   BACKGROUND

     A.  Biogenesis is the owner of certain technology and proprietary rights
         in and to a unique fire suppressant technology;

     

     B.  Summit and BioGenesis desire to enter into an agreement whereby
         ownership of the technology and related trademarks, patents, patent
         applications and all enhancements thereto (hereinafter the
         "Intellectual Property") is transferred from BioGenesis to Summit.

NOW, THEREFORE, subject to the terms and conditions set forth herein, and to 
the execution of formal agreements consistent with the terms of this letter of 
intent, the parties agree as follows:

     1.  TRANSFER.  Biogenesis will transfer to Summit (or its successor) the
         Intellectual property and will execute and deliver to Summit all data,
         formulas and information relevant thereto. 

     2.  CONSIDERATION.  Summit will pay to BioGenesis, in consideration for 
         the transfer of the Intellectual Property, the following:

         A.  Cash in the amount of $425,000.00, representing the balance of a 
             one-time, non-refundable royalty (the "Initial Royalty");
         B.  Cash, in the amount of $500,000, representing an advance payment 
             of periodic royalties (the "Advanced Royalty"), as set forth 
             herein; and 
         C.  750,000 shares of common stock of Summit.

     3.  PAYMENT.  Payment of the Initial Royalty and Advance Royalty fees 
         shall be made as follows:

         A.  $25,000 on or before May 1, 1998;
         B.  $100,000 on or before June 1, 1998; and

                                                                    Exhibit 10.7
                                                               Page 2 of 4 Pages
    

<PAGE>   3
   
          C.   the balance of $800,000 upon the earlier of November 15, 1998, or
               ten (10) days following the completion of a secondary stock
               offering by Summit intended to finance the transfer (the
               "Closing"); and
          D.   the Common Stock shall be delivered to BioGenesis at the Closing.

     4.   ADVANCE ROYALTY AND PERIODIC ROYALTIES. Summit shall pay to BioGenesis
          a periodic royalty of $.50 per 16-oz can and an equivalent
          (approximately 7%) on all other product categories using the fire
          suppressant technology.  One-half of all periodic royalty fees due to
          BioGenesis shall be credit against the Advance Royalty fee (until
          fully recovered) and one-half shall be paid to BioGenesis in cash on
          the 30th of each month based upon invoiced sales through the close of
          the preceding month.

     5.   EXISTING SALES AND MARKETING AGREEMENTS. Summit acknowledges that the
          transfer is subject to certain existing sales, marketing and
          distribution agreements previously entered into by BioGenesis. The
          parties agree to cooperate concerning the administration and/or
          termination of these arrangements, as appropriate. Between the
          execution of formal agreements confirming this letter of intent and
          the Closing, BioGenesis shall be entitled to all profits from such
          arrangements. Following the Closing, all net profits shall be the
          Property of Summit; provided, however, BioGenesis shall be entitled to
          an administration fee of ten (10%) percent of the direct cost of goods
          on such sales so long as it administers such arrangements.

     6.   OPTION ON FUTURE PRODUCTS. Summit shall have an option to acquire the
          rights to a biodegradable anti-freeze and neutralizing agent and a
          deicer product created by BioGenesis upon the periodic royalty
          structure set forth herein.

     7.   FORMAL AGREEMENT. The parties obligation hereunder are subject to the
          completion of due diligence and to the preparation and execution of
          formal agreements consistent with the terms of this letter of intent
          and otherwise acceptable in form to their respective counsel.

     8.   TERMINATION. If the Closing does not take place on or before November
          15, 1998, or such other date thereafter as the parties shall agree,
          then this letter of intent

                                                                    Exhibit 10.7
                                                               Page 3 of 4 Pages
    

<PAGE>   4
   
          shall be terminated and the parties shall revert to the existing
          license arrangement between them, with all sums paid by Summit
          hereunder credited to amounts due under that agreement.

     IN WITNESS WHEREOF, the parties have executed this letter of intent at
     Dallas, Texas, as of the date first above written.

                                       BIOGENESIS ENTERPRISES, INC.



                                       By: /s/ MOHSEN C. AMIRAN
                                          ---------------------------------
                                          Mohsen C. Amiran, President


                                       SUMMIT TECHNOLOGIES, INC.


                                       By: /s/ B. KEITH PARKER
                                          ---------------------------------
                                          B. Keith Parker, CEO


                                                                    Exhibit 10.7
                                                               Page 4 of 4 Pages