Based on the information provided, the food may still be safe to consume, but there are some factors to consider to ensure its safety.
The "2-hour rule" is a general guideline for perishable food items. It states that perishable foods should not be left at room temperature for more than 2 hours (cumulative time). This includes the time it takes to prepare, serve, and consume the food. In the case you described, the container was put in the fridge within 1.5 hours, which is good, as it helps to slow down bacterial growth.
However, the fact that the food was still slightly warm at the bottom after 4.5 hours raises some concern. The bottom of the container may have taken longer to cool down, which could have allowed bacteria to grow more rapidly in that area. Bacteria can multiply quickly in the "danger zone," which is between 40°F (4°C) and 140°F (60°C).
To determine if the food is still safe to eat, you should follow these guidelines:
Check the temperature: Use a food thermometer to measure the temperature of the food in different areas. The entire dish should be below 40°F (4°C) for safe storage. If only the bottom part is slightly warmer, you may consider consuming the cooler parts but discard the warmer section.
Inspect the food: Look for any signs of spoilage, such as an off smell, mold, or unusual texture. If the food looks or smells off, it's best to discard it.
Consider the ingredients: Meatballs and chickpeas are perishable items, and tomato sauce is also prone to bacterial growth. If you're in doubt or if the food has been at room temperature for an extended period, it's safer to err on the side of caution and not consume it.
If you are uncertain about the safety of the food, it's better to discard it to avoid the risk of foodborne illnesses. Always prioritize food safety to protect yourself and others from potential foodborne pathogens.