You are an AI assistant that aids users in performing data analysis using Python and Pandas to find information.

There is the dataset: you have the datafastfoodcontains the following columns:['restaurant', 'item', 'calories', 'cal_fat', 'total_fat', 'sat_fat', 'trans_fat', 'cholesterol', 'sodium', 'total_carb', 'fiber', 'sugar', 'protein', 'vit_a', 'vit_c', 'calcium', 'salad'].
--- The description for each column this data is:
restaurant: Name of fast food restaurant (McDonalds, Chick Fil-A, Sonic...etc)
item: Menu item at the restaurant (Artisan Grilled Chicken Sandwich, Single Bacon Smokehouse Burger, and Big Mac...etc) 
calories: Energy content of the food item (measured in calories) 
cal_fat: Calories in the item come from fats (measured in calories)
total_fat: Total amount of fat in the item (measured in grams)
sat_fat: The amount of saturated fat in the item (measured in grams) 
trans_fat: Trans fat content of the item (measured in grams) 
cholesterol: Cholesterol content of the item (measured in milligrams)
sodium: Sodium content of the item (measured in milligrams)
total_carb: Total carbohydrates in the item (measured in grams)
fiber: Dietary fiber content of the item (measured in grams)
sugar: Total sugar content in the item (measured in grams)
protein: Total protein content in the item (measured in grams)
vit_A: Vitamin A content in the item (measured in a percentage of the recommended daily intake) 
vit_C: Vitamin C content in the item (measured in a percentage of the recommended daily intake) 
calcium: Calcium content in the item (measured in a percentage of the recommended daily intake) 
salad: Type of food item (main course, side dish, or dessert)
---
Considering contents from the dataset and result types from user, you only need to generate codes and notations. Please note DO NOT CHANGE FILE AND VARIABLE NAMES THAT I HAVE SET!
Conversation begins:

[USER (data scientist)]:Please filter the dataset to include only main course items such as sandwiches, wraps, and salads, and exclude side dishes and desserts. Then, provide the filtered dataset containing only main course items. Please load the 'fastfood.csv' dataset into a DataFrame, then filter it to include only rows where the 'item' column contains one of several keywords related to fast food items (making the search case-insensitive), and finally, save the filtered DataFrame as a pickle file. 

My template of code snippet is:

---BEGIN CODE TEMPLATE---
import pandas as pd
import numpy as np
import pickle

atp_tennis = pd.read_csv('atp_tennis.csv')

# YOUR SOLUTION BEGIN:
<code1>
[COMPLETE YOUR CODE]  
</code1>
# YOUR SOLUTION END 

print(federer_match_ids)
pickle.dump(federer_match_ids,open("./pred_result/federer_match_ids.pkl","wb"))
---END CODE TEMPLATE---

Please note that you have to generate the WHOLE python code instead of code segments based on the code snippet using Pandas library 2.0.3 version and Matplotlib library 3.7.4 version. You must keep all comments in code snippet unchanged.

[YOU (AI assistant)]: