Is Moldy Cheese Safe to Eat?

The process of cheese making starts with separating the solid milk curds from the liquid whey. This is usually facilitated by acidifying fresh milk. Commercially, this acidification process is known as curdling and it is characterized by the addition of rennet and some bacterial cultures. The cultures can be eliminated since vinegar or some lemon juice will help the milk to curdle just as well. Rennet is a necessary ingredient in cheese making and it is a natural compound found in the fourth stomach of unweaned ruminants. It is acidic and helps the young animals to digest the milk.

Rennet is very important indeed in cheese making since it makes the curds rubbery and gel like in texture as opposed to the loose curds from acidifying the milk only. This foundation is important to lay if we are going to answer the question of the safety of moldy cheese effectively. Well, the answer is both yes and no. If you are going to eat moldy cheese, you need to get some facts straight first. You cannot just trim off the mold and continue eating the cheese you need to know what kind of cheese it is before doing this.

Some people confuse bacteria and fungus. You may think that since some bacteria is added into the cheese making process then it is safe to eat moldy cheese. However, there is a difference between bacteria and mold. Mold is a fungus and the bacteria used in cheese making is done so in a controlled environment and so it is safe for human consumption. The bacteria adding step in most cheese making processes is usually skipped as long as another option is available to aid in the acidifying of the milk curds.

It is important to point out that some mold is used in the production of some cheeses especially the blue ones and the soft ripened ones like camembert and brie. Penicillium is the most commonly used mold and some cheese names actually come from the type of mold used, for example, Roquefort made from penicillium roqueforti. Notice it is some and not all or most cheeses. Any mold that was not incorporated in the production process means that something is wrong. The assumption that cheese is just mold so it is safe to consume moldy cheese is very wrong.

As a rule of thumb, any mold on soft cheese such as goats, feta and cottage cheeses, is an indication that it has gone bad and should be thrown out. This is true for any grated cheese, whether hard or soft. The structure of soft cheese allows the mold to penetrate deeper into the cheese and spoil the entire block. It is an avenue for diseases through dangerous bacteria such as brucella, listeria and E. coli. Mold on hard and semi-soft cheeses such as Swiss, Colby and Cheddar can be scrapped off and the cheese eaten safely. Just make sure you cut at least an inch around and into the mold. Keep the knife from touching the mold to avoid the risk of contaminating other parts of the cheese block.