What is the importance of starter cultures?
- They are used in cheese production to generate acid
- They contribute to the structure and safety of cheese
- They have a positive effect on the flavor and aroma of cheese
What are the types of cultures?
- Mesophilic cultures (excellent growth temperature ~26-30ο C Feta cheeses)
- Thermophilic cultures (excellent growth temperature ~42ο C)
- Secondary
- Non-starter lactic acid bacteria (NSLAB)
- Deriving from milk, the equipment and raw materials used in cheese making.
- Their significance in the creation of flavor and aroma of cheese.
COAGULATION
The following risks may appear at this stage:
- The appearance of bacteria through the equipment or the environment.
- Lactic acid culture being slow or defective, resulting in the low acidity of milk for a long time; something that would allow the growth of unwanted bacteria at non-acceptable levels.
Inspection of these risks:
- Ensure the proper cleaning of the premises and equipment.
- Use of active lactic acid culture at the right proportion.
- Ensure that the product’s acidity is within the acceptable limits for this particular cheese being produced. This can be done with a simple pH meter during the cheese production stages.
DIVISION AND HANDLING OF CURD
This procedure might incur the following risk:
- Microbial contamination from the equipment and personnel.
Inspection of these risks:
- Ensure that the tools used for curd cutting are clean and disinfected beforehand.
Check personnel for infections (salmonellosis, open wounds)
SALTING, FILLING OF MOLDS AND PRESSING
The main risks for these procedures are the following:
- Contamination of the curd from the salt or brine
- Contamination of the curd from the equipment, the cheese cloth, or the personnel.
Inspection of these risks:
- Store the salt in a clean, dry and well-ventilated space.
- Macroscopic examination of the salt for foreign bodies before being added to the cheese.
- Ensure that all equipment and cheese cloth are clean and disinfected beforehand.
- Ensure that the personnel is clean and healthy.
- Check that the brine is at least 50% saturated. The more powerful the brine solution, the safest it is.
- Remove any curd pieces from the brine.
- Change the brine at regular intervals or pasteurize it.
RIPENING
Ripening is a critical stage in the creation of the final
product.
The most important points that need attention are the following:
- Generally, it is necessary to ensure over 85% humidity in the space. If the humidity is low, then some corrective actions must be made in the ripening chamber, such as the use of a humidifier, or placing containers of drinking water on the floor of the ripening chamber, or covering the cheese with a clean cloth or paper.
- The temperature required for cheese to ripen is different for each type (depends not only from the type of cheese, but also from the producer and the production date). Also, the ripening stage and the time desired for its ripening are critical factors.
- Cheese must be inverted frequently, so that the moisture can be evenly distributed throughout its body. At the initial stages of ripening, cheese must be inverted daily and gradually every month for mature cheese.
- Some cheese develop fungi or bacteria on the surface (appearing as a thin coating of whitish or brownish red color), but this is part of the ripening process. Therefore, in this case, the ripening conditions must favor the growth of these fungi or bacteria.
- If this surface coating is not desirable, the cheese must be cleaned with the use of a saline solution (brine).
- Some cheeses do not ripen at the specified time, so the cheesemaker shall decide on the batches that are ready for sale.
- It is essential for the cheesemaker to know that views over cheese ripening vary, and occasionally do not coincide with those of consumers.
The growth of undesirable fungi or bacteria may occur when:
- Cheese is kept at improper temperatures or humidity.
- Ripening time is not enough to allow cheese to ripen properly.
- Fungi and bacteria contaminate cheese during storage, from the shelves where they are placed or the environment.
- Insects or other animals may enter the ripening room and contaminate the cheese.
Inspection of these risks:
- Storage of cheese at the right temperature, allowing the development of its aroma and structure, and eliminating the growth of undesirable bacteria. The recommended temperature must generally be lower than 15ο C, taking into consideration that it depends on the type of cheese and other factors.
- Storage at a space with the right humidity, depending on the type of cheese. When the development of surface fungi or bacteria is undesirable, lower temperature is required, and when is desirable, higher temperature is required.
- Storage of cheese for the duration provided depending on its type. Ensure that the ripening chamber and the shelves where the cheese is placed are clean. It is advisable to have a cleaning schedule for the ripening chamber and the storage area and meticulously keep it.
- To ensure there is an inspection system to prevent insects or harmful animals from entering the ripening chamber, which might result in the contamination of cheese.
Dr. Georgios Samouris
Director of Research
Dr. Evdoxios Psomas
Commissioned Researcher
