How to get rid off blank record generated through Repeater Fields

I have created a Meta Box in my custom post types and added a code to create repeater (Add/remove dynamic fields) fields. Following is the code:

function add_project_reward_meta_box( $post ) {

    add_meta_box(

        'project-reward-meta-box',
        __( 'Rewards' ),
        'project_reward_callback',
        'project',
        'normal',
        'high'

    );

}

add_action( 'add_meta_boxes_project', 'add_project_reward_meta_box' );

function project_reward_callback( $post ) {
    wp_nonce_field( 'group_project_reward_nonce', 'project_reward_nonce' );
    $reward_value = get_post_meta( get_the_ID(), '_project_rewards', true );

?>

    <script type="text/javascript">
    jQuery(document).ready(function( $ ){
        $( '#add-row' ).on('click', function() {
            var row = $( '.empty-row.screen-reader-text' ).clone(true);
            row.removeClass( 'empty-row screen-reader-text' );
            row.insertBefore( '#repeatable-fieldset-one tbody>tr:last' );
            return false;
        });

        $( '.remove-row' ).on('click', function() {
            $(this).parents('tr').remove();
            return false;
        });
    });
    </script>

    <table id="repeatable-fieldset-one" width="100%">

    <thead>
        <tr>
            <th>Reward Amount</th>
            <th>Reward Title</th>
            <th>Reward Description</th>                             
        </tr>
    </thead>

    <tbody>

<?php

    ( $reward_value );

    foreach ( $reward_value as $field ) {

?>

    <tr>
        <td><input type="text" class="widefat" name="reward[]" value="<?php if($field['reward'] != '') echo esc_attr( $field['reward'] ); ?>" /></td>

        <td><input type="text" class="widefat" name="reward_title[]" value="<?php if ($field['reward_title'] != '') echo esc_attr( $field['reward_title'] ); ?>" /></td>

        <td><input type="text" class="widefat" name="reward_description[]" value="<?php if($field['reward_description'] != '') echo esc_attr( $field['reward_description'] ); ?>" /></td>

        <td><a class="button remove-row" href="#">Remove</a></td>
    </tr>

<?php } ?>

    <!-- empty hidden one for jQuery -->
    <tr class="empty-row screen-reader-text">
        <td><input type="text" class="widefat" name="reward[]" /></td>

        <td><input type="text" class="widefat" name="reward_title[]" /></td>

        <td><input type="text" class="widefat" name="reward_description[]" /></td>

        <td><a class="button remove-row" href="#">Remove</a></td>
    </tr>

    </tbody>

    </table>

    <p><a id="add-row" class="button" href="#">Add another</a></p>

<?php   

}

function save_project_reward( $post_id ) {

    // Check if our nonce is set.
    if ( ! isset( $_POST['project_reward_nonce'] ) ) {
        return;
    }

    // Verify that the nonce is valid.
    if ( ! wp_verify_nonce( $_POST['project_reward_nonce'], 'group_project_reward_nonce' ) ) {
        return;
    }

    // If this is an autosave, our form has not been submitted, so we don't want to do anything.
    if ( defined( 'DOING_AUTOSAVE' ) && DOING_AUTOSAVE ) {
        return;
    }

    // Check the user's permissions.
    if ( isset( $_POST['post_type'] ) && 'page' == $_POST['post_type'] ) {

        if ( ! current_user_can( 'edit_page', $post_id ) ) {
            return;
        }

    }
    else {

        if ( ! current_user_can( 'edit_post', $post_id ) ) {
            return;
        }
    }

    $reward_data = array();

    $rewards = $_POST['reward'];
    $reward_titles = $_POST['reward_title'];
    $reward_descriptions = $_POST['reward_description'];

    $count = count( $rewards );

    for ( $i = 0; $i < $count; $i++ ) {

            $reward_data[$i]['reward'] = stripslashes( strip_tags( $rewards[$i] ) );
            $reward_data[$i]['reward_title'] = stripslashes( strip_tags( $reward_titles[$i] ) );
            $reward_data[$i]['reward_description'] = stripslashes( strip_tags( $reward_descriptions[$i] ) );

    }

            update_post_meta( $post_id, '_project_rewards', $reward_data );

}

add_action( 'save_post', 'save_project_reward' );

Everything is working fine but the only problem I am facing is that once the post is published the repeater field is unnecessarily creating a blank record in the database and also displaying the blank fields of that record on post edit page. Plz help me out to get rid off the blank record.

Also is the code is perfectly sanitized? If no, Plz suggest me the process.

Thanks.