Ricotta cheese is used to increase the depth of flavor in many dishes such as gnocchi, pasta, and lasagna as well as many sauces. It is one of the most commonly used cheeses in Italy and is very popular across the rest of the world.
So, what are you to do when you go to your fridge to use your ricotta, only to find it has patches of mold growing in it? Is the moldy cheese still safe to eat? Can you scrape off the mold and eat the rest and how can you stop this from happening again?
In this article, we answer all these questions and more, so, for all you need to know about mold growth in ricotta cheese, keep reading.
Why does ricotta cheese get moldy?
Mold only needs a few things in order to thrive on foods, which are, a high enough moisture content, nutrients, and the optimal temperature range for it to spread.
As Ricotta cheese is a soft cheese, it naturally has a higher water content than other cheeses such as cheddar, this allows mold to use the liquid as a source of hydration. It also contains the fats, proteins, minerals, and carbohydrates mold can use as a food source.
Keeping ricotta cheese in the fridge will certainly slow the rate at which mold grows, but once the container is opened, certain strains can still grow, (albeit at a slower rate than if the cheese was kept at room temperature).
As soon as the ricotta is taken out of the fridge, its temperature will rise, if this is allowed to continue, once the cheese reaches room temperature mold can begin to grow at its most rapid rate. Anything over 60 degrees Fahrenheit will allow mold to grow very quickly, and it will become very well-established within the cheese in only a matter of a couple of hours.
What types of mold grow on ricotta cheese?
The most common strains of mold to grow in ricotta cheese are penicillium and Mucor genera.
Penicillium is commonly found growing within soil, decaying vegetation, cereals, and fresh fruit and vegetables. Cross contamination and airborne spores as the most likely cause of this strain growing in ricotta cheese.
Mucor genera are again found in similar locations to penicillium but are also commonly seen in animal dung. Cross-contamination during the milking process is a likely cause of this strain finding its way into the final product.
Cows milk goes through the pasteurization process after being collected which exposes it to extreme heat. Whilst this does kill most strains of bacteria, it can simply put some strains of mold into a state of hibernation, allowing them to become active once again when the temperature lowers to an acceptable level.
Similarly, placing food items in the refrigerator does not kill mold, instead, it will once again go into a state of hibernation, and its rate of growth drops until the temperature is correct for it to become active once more.
What color is mold on ricotta cheese?
Penicillium strains often begin as small white circular growths with a powdery or velvet-like texture. Over time its coloration can change, turning blue to blue-green to a darker olive green.
The Mucor strains have a similar process and begin life as small patches of white to beige growths, and over time, eventually, turn more gray in color. The main visual difference between Mucor and penicillin strains is that Mucor has a more cotton-like or “fluffy” texture.
Can moldy ricotta cheese make you sick?
Ingesting moldy ricotta cheese certainly can make you ill, especially if the person consuming it is allergic to the strains present, or has a suppressed immune system.
Even otherwise healthy individuals can suffer from unpleasant symptoms after ingesting or inhaling the spores from foods with penicillium or mucor strains present, and these include:
- Gastrointestinal discomfort
- Fatigue (in rare cases)
- Skin irritation
Another issue to consider is that mold often grows at its most rapid rate under the same conditions as bacteria, and so there is a very real possibility that if mold is seen growing on ricotta cheese, large amounts of bacteria could also be present, so food poisoning is another cause for concern.
This is not to say that every person who eats a small amount of mold in ricotta cheese will suffer from these symptoms. In fact, many would suffer little to no issue as long as they only ingested a small amount and stopped once they had noticed the cheese had gone bad.
Can you scrape off the bad parts from ricotta cheese?
Scraping mold off the top layer of ricotta cheese and eating the rest is not advisable, as this would only remove the visible layer of mold.
When mold grows in soft cheeses such as ricotta, it grows roots, (also known as threads). These threads can pass down into the deeper parts of the cheese and will remain even when the visible growth is removed.
Molds also release mycotoxins, a toxic substance used as a defense mechanism whenever it feels threatened. If these mycotoxins are present within the cheese, scraping the top layer off would not remove them, and they could cause illness if the rest of the cheese were to be eaten.
The most likely time for any type of cheese to grow mold is once it has begun to turn rancid, so in all likelihood, once the cheese has begun to grow mold, it has most likely already gone bad and would be very unpleasant to eat anyway.
How to prevent mold on ricotta cheese
Preventing mold growth on ricotta cheese comes down to ensuring it is stored properly once it is purchased. Keeping it under conditions that make it difficult for mold and bacteria growth will extend its shelf-life and preserve its taste and texture.
Here are some preventative methods you can use to extend the life of your ricotta cheese and prevent mold and bacteria growth.
Keep it in an air-tight container
If not using the full container of ricotta cheese in one sitting, place the remaining cheese into an airtight container. Decreasing airflow helps to prevent cross-contamination of any mold spores or bacteria that may be within the refrigerator from finding their way onto the cheese, and helps to keep the temperature more stable.
The bottom part of the fridge maintains its temperature more consistently, and as even small increases in temperature can influence the speed at which mold grows, keeping this as stable as possible will help prevent mold from growing.
If possible, store the ricotta towards the back of the refrigerator also, as this is the furthest point from the door, so will be less affected by temperature fluctuations when the door is opened and closed.
Check its use-by date
Best-before dates mean very little in terms of how long the actual product will last, however, use-by dates are far more useful.
The date shown as the day and month the product should be used dictate how long the ricotta will stay at its most fresh, after this point, the cheese is more likely to begin to spoil and become rancid. This is also the point by which the cheese will begin to possibly grow mold.
When purchasing ricotta cheese, check the use-by date and make sure it is within the time period you plan on using the product. You can usually add a few days onto the use by state and still have the product be safe to eat, but after the date shown, the product will already be past its best.
If you have purchased more ricotta cheese than you can use before the expiration date, you do have the option to freeze it.
Whilst this may spoil the texture and could decrease the intensity of its flavor, it will certainly slow any mold or bacteria growth.
Once thawed, the cheese can still be used in sauces and other baked recipes. The former creamy texture can sometimes be regained with vigorous whisking, although this is not always the case.
Do not leave it out at room temperature
As soon as ricotta cheese is taken out of the fridge, it begins to warm, and as this happens mold and bacteria can begin to awaken from their hibernation and start to spread.
If you only need a small amount of ricotta cheese, put the rest of the container back in the fridge as quickly as possible. If it is left on the counter for too long, it can quickly spoil, and in this circumstance, the cheese should be discarded.
Check your fridge door seals and thermostat
Even small increases in temperature can awaken the mold and bacteria that may already be within your ricotta cheese, so keeping the temperature of the fridge as constant as possible will help to prevent this.
Check the seals (called gaskets), on the door of your refrigerator to check for any signs of deterioration. Replace any broken seals promptly, as when these seals are damaged, warm air can enter, and cold air can escape, making the motor of the fridge work harder to try to maintain the temperature inside.
It’s also worth checking that the thermostat is set to the correct temperature (40 degrees Fahrenheit or lower is best for ricotta), and keep a thermometer within the fridge so you can ensure the temperature matches what the thermostat has been set to.
Ricotta cheese grows mold and bacteria more quickly than hard cheeses due to its high water content. These molds can cause symptoms in those with weakened immune systems and can cause allergic reactions, they can also infiltrate the entire tub of cheese, so scraping off the top layer and eating the rest is not advised.
Storing the cheese in an airtight container at the bottom of a refrigerator at 40 degrees Fahrenheit or lower is the best way to prevent mold growth and extend its shelf life.