SupplyChain.sol

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

...

//Item State Modifiers
    modifier producedByFarmer(uint256 _productCode) {
        require(items[_productCode].itemState == State.ProduceByFarmer);
        _;
    }

    modifier forSaleByFarmer(uint256 _productCode) {
        require(items[_productCode].itemState == State.ForSaleByFarmer);
        _;
    }

    modifier purchasedByDistributor(uint256 _productCode) {
        require(items[_productCode].itemState == State.PurchasedByDistributor);
        _;
    }

    modifier shippedByFarmer(uint256 _productCode) {
        require(items[_productCode].itemState == State.ShippedByFarmer);
        _;
    }

    modifier receivedByDistributor(uint256 _productCode) {
        require(items[_productCode].itemState == State.ReceivedByDistributor);
        _;
    }

    modifier processByDistributor(uint256 _productCode) {
        require(items[_productCode].itemState == State.ProcessedByDistributor);
        _;
    }

    modifier packagedByDistributor(uint256 _productCode) {
        require(items[_productCode].itemState == State.PackageByDistributor);
        _;
    }

    modifier forSaleByDistributor(uint256 _productCode) {
        require(items[_productCode].itemState == State.ForSaleByDistributor);
        _;
    }

    modifier shippedByDistributor(uint256 _productCode) {
        require(items[_productCode].itemState == State.ShippedByDistributor);
        _;
    }

    modifier purchasedByRetailer(uint256 _productCode) {
        require(items[_productCode].itemState == State.PurchasedByRetailer);
        _;
    }

    modifier receivedByRetailer(uint256 _productCode) {
        require(items[_productCode].itemState == State.ReceivedByRetailer);
        _;
    }

    modifier forSaleByRetailer(uint256 _productCode) {
        require(items[_productCode].itemState == State.ForSaleByRetailer);
        _;
    }

    modifier purchasedByConsumer(uint256 _productCode) {
        require(items[_productCode].itemState == State.PurchasedByConsumer);
        _;
    }
    
    ...