diff --git a/app/controllers/isolates_controller.rb b/app/controllers/isolates_controller.rb
index fb5ab792..5dd87d2a 100644
--- a/app/controllers/isolates_controller.rb
+++ b/app/controllers/isolates_controller.rb
@@ -59,7 +59,11 @@ def import
     file = params[:file]
 
     if file
-      IsolateImporter.perform_async(params[:file], current_user.default_project_id)
+      file_name = file.original_filename
+      path = File.join("tmp", file_name)
+      File.open(path, "wb") { |f| f.write(file.read) }
+
+      IsolateImporter.perform_async(path, current_user.default_project_id)
       redirect_to isolates_path,
                   notice: "Isolate and specimen data will be imported in the background."
     else
diff --git a/app/models/isolate.rb b/app/models/isolate.rb
index 144ef33f..d706e37e 100644
--- a/app/models/isolate.rb
+++ b/app/models/isolate.rb
@@ -49,8 +49,8 @@ class Isolate < ApplicationRecord
   scope :recent, -> { where('isolates.updated_at > ?', 1.hours.ago) }
   scope :no_controls, -> { where(negative_control: false) }
 
-  def self.import(file, project_id)
-    spreadsheet = Isolate.open_spreadsheet(file)
+  def self.import(file_path, project_id)
+    spreadsheet = Roo::CSV.new(file_path)
     header = spreadsheet.row(1)
 
     (2..spreadsheet.last_row).each do |i|
diff --git a/app/workers/isolate_import.rb b/app/workers/isolate_importer.rb
similarity index 92%
rename from app/workers/isolate_import.rb
rename to app/workers/isolate_importer.rb
index b4ba0dc5..9f86de40 100644
--- a/app/workers/isolate_import.rb
+++ b/app/workers/isolate_importer.rb
@@ -26,7 +26,7 @@
 class IsolateImporter
   include Sidekiq::Worker
 
-  def perform(file, project_id)
-    Isolate.import(file, project_id)
+  def perform(file_path, project_id)
+    Isolate.import(file_path, project_id)
   end
 end
\ No newline at end of file