<PAGE>   1
                                                                   EXHIBIT 10.91


           SECOND ADDENDUM TO THE MANUFACTURING AND SUPPLY AGREEMENT
                             DATED FEBRUARY 3, 1997

This Second Addendum Agreement ("the Second Addendum Agreement") to the
Manufacturing and Supply Agreement ("the Master Agreement") is made effective
on the 3rd day of February, 1997 ("Effective Date") by and between Wilshire
Technologies, Inc. ("WTI"), a California corporation with a place of business
at 5441 Avenida Encinas, Suite A, Carlsbad, California 92008 and Advanced
Barrier Technologies, Inc. ("ABT"), a California corporation with a place of
business at 2120 Las Palmas, Suite F, Carlsbad, CA  92009.

                                    RECITALS
                                    --------

WHEREAS, WTI,  a manufacturer and supplier of clean room swabs used for
specialized applications in the electronics industry, and ABT,  a manufacturer
with a production facility in Tijuana, Mexico, entered into the Master
Agreement dated April 11, 1996;

NOW THEREFORE, the parties hereto agree to amend certain sections of the Master
Agreement which are hereby superseded by the amended sections as follows:


         1.3     WTI Equipment shall mean the special production equipment
listed on Exhibit A of the Master Agreement, the R & D Equipment listed on
Exhibit D of the Addendum Agreement dated July 26, 1996, and the WCC Equipment
listed on Exhibit F of this Second Addendum Agreement attached hereto, owned by
WTI and installed at the Tijuana Facility for the purpose of manufacturing the
Product, and the WCC Product.

         1.4     WTI Technology shall mean all inventions, intellectual
property, technical data and know-how of WTI, including any issued patent and
patent applications, and any extensions and reissues thereof, relating to the
method and process of manufacturing breathable polyurethane gloves and clean
room swabs and wipes.

         1.5     WCC Product shall mean WTI's proprietary clean room swabs
manufactured and processed by ABT for WTI pursuant to the terms of the
Agreement and this Second Addendum Agreement, as described in Exhibit G.

         3.1     WTI shall procure the WTI Equipment at its expense.  WTI will
pay the WTI Equipment suppliers directly per the terms agreed between such
suppliers and WTI.  WTI will maintain a petty cash fund for purchases of small
parts needed to install the WTI Equipment. WTI will pay ABT to install the WTI
Equipment in the Tijuana Facility in accordance with the terms of payment for
Phase 1 in Exhibit C of the Master Agreement,  in Exhibit E to the Addendum
Agreement, and in Exhibit G to this Second Addendum Agreement.  All title and
ownership in the WTI Equipment shall be retained by WTI, and ABT shall not
permit any lien or third party claim to be asserted with respect to the WTI
Equipment.  Further, ABT shall cooperate with WTI to ensure that all WTI
Equipment is clearly and conspicuously labeled "Property of Wilshire
Technologies, Inc."





                                       1
<PAGE>   2
         4.2     The sole and exclusive compensation payable by WTI to ABT for
the Manufacturing Services will be as listed on Exhibit C to the Master
Agreement, Exhibit E to the Addendum Agreement, and Exhibit G to this Second
Addendum Agreement.


         IN WITNESS WHEREOF, the parties hereto have caused this Second
Addendum Agreement to the Master Agreement to be executed by their duly
authorized representatives.

WILSHIRE TECHNOLOGIES, INC.                ADVANCED BARRIER TECHNOLOGIES, INC.



By:     /s/ John Van Egmond                By:     /s/ Ralph M. Sias        
     ---------------------------                  ----------------------    
         John Van Egmond                           Ralph M. Sias

Title:   President & CEO                   Title:   President                
         ------------------------                  ---------------------     


Date:    3/10/97                           Date:     3/27/97
         ------------------------                 ----------------------   





                                       2
<PAGE>   3
           SECOND ADDENDUM TO THE MANUFACTURING AND SUPPLY AGREEMENT
                             DATED FEBRUARY 3, 1997


                                   EXHIBIT F

                                 WCC Equipment
                                 -------------




                                       3
<PAGE>   4
           SECOND ADDENDUM TO THE MANUFACTURING AND SUPPLY AGREEMENT
                             DATED FEBRUARY 3, 1997

                                   EXHIBIT G

                        MANUFACTURING SERVICES PAYMENTS
                             FOR THE WCC EQUIPMENT

PHASE 1 -  PREPARATION OF FACILITY AND INSTALLATION OF EQUIPMENT

Term:            From the Effective Date of this Second Addendum Agreement
                 until the date that the WCC Equipment has operated for one 
                 Shift. A "Shift" is defined as 48 hours per week.

Payments:        WTI will pay ABT $2.80 per manhour as reimbursement for the
                 direct labor costs related to installation of the WCC Equipment
                 in the Tijuana Facility, according to WTI specifications. ABT
                 shall pay all rent, insurance, and taxes, and related utilities
                 as provided in the Master Agreement.

                 WTI will pay ABT at the rate paid by ABT as reimbursement for
                 the skilled labor costs (eg. line supervisor, quality control
                 technician, maintenance technician, engineer, etc.) related to
                 operating the WCC Equipment in the Tijuana Facility, according
                 to WTI specifications. WTI will pay all incoming and outgoing
                 freight related to the WCC Product.

PHASE 2 - PRODUCTION

Term:            From the date that the WCC Equipment operates for one Shift
                 until this Second Addendum Agreement is terminated. A "Shift"
                 is defined as 48 hours per week.

Payments:        WTI will pay ABT $2.80 per manhour as reimbursement for the
                 direct labor costs related to operating the WCC Equipment in
                 the Tijuana Facility, according to WTI specifications. ABT
                 shall pay all rent, insurance, and taxes, and related
                 utilities as provided in the Master Agreement.

                 WTI will pay ABT at the rate paid by ABT as reimbursement for
                 the skilled labor costs (eg. line supervisor, quality control
                 technician, maintenance technician, engineer, etc.) related to
                 operating the WCC Equipment in the Tijuana Facility, according
                 to WTI specifications. WTI will pay all incoming and outgoing
                 freight related to the WCC Product.

                 At the conclusion of each production week, ABT shall forward
                 its invoice for such manufacturing service fees to WTI via
                 fax.  WTI shall pay such invoices on a net 15 day basis from
                 the date of such invoice.





                                       4