Mozzarella is a fresh unmatured stretched curd cheese, originating from Campania (South-West Italy) where it was and is still made, as well as recognized by a specific PDO– starting from buffalo milk.
Most Italian mozzarella, including the famous one PDO from Gioia del Colle (Puglia, South-East Italy), is today made with cow’s milk (mozzarella milk cream), or with a mixture of buffalo and cow’s milk. In rare cases also with sheep or goat’s milk.
1) Mozzarella production technology
1.1) Pasteurization
The traditional production of mozzarella was done from raw milk. However, the due attention to microbiological risks has prevailed over tradition and the undisputed superior sensorial quality. (1,2) Today, therefore, only pasteurized milk is used.
1.2) Coagulation
The milk is heated to 35-40°C, inside multipurpose tanks where rennet and lactic ferments are then added. As an alternative to the latter, organic acids can be used, such as citric acid or lactic acid. The difference, however, is substantial:
– lactic ferments allow slower acidification and the development of characteristic sensory compounds that give the mozzarella a superior quality
– organic acids allow faster coagulation. This speeds up production times, to the detriment of the organoleptic quality of the product. (3)
The rennet in an acidic environment allows the coagulation of caseins (milk proteins) with fats and the formation of a ‘caseous mass’ which precipitates and separates from the whey.
2) Breakage of the clot and maturation
The next stage is the breaking of the clot, through special ‘mechanical pins’ which reduce it into granules. This is followed by positioning on wheeled tables and maturation in a room at a temperature of 35-40 °C and 90-99% humidity.
The shattering of the clot allows you to release the remaining whey. The acidic environment also allows the demineralization of the curd, i.e. the passage of calcium and phosphorus from the casein into the whey, thus facilitating the subsequent stretching phase.
3) Spinning
Spinning is the only heat treatment in the mozzarella production process. It is made at the end of maturation, immersing the curd in hot water (80-90 °C), with different purposes:
– obtain a stretching of the casein micelles and the formation of a silky and plastic paste
– partially inactivate the rennet, slowing down its coagulant and proteolytic activity
– inhibit spoilage and/or pathogenic microorganisms that may be residual from previous processes, also due to accidental contamination during the production process (4,5).
At the end of the spinning, the mozzarella is shaped into the typical ball shapes, or stretched to obtain the braided shape.
4) Firming and packaging
The last stage is immersion in two solutions:
- in cold water (< 15 °C), in hardening tanks, to lower the temperature of the product
- in brine, in special tanks of water with a salt concentration of around 20%, where the salt is absorbed by osmosis.
The mozzarellas are finally packaged, in bags or trays, in the preserving liquid (a solution of water, lactic or citric acid, whey proteins, sodium chloride and residual lactic ferments). This liquid performs important technological functions such as prolonging life shelf lifeof the product and maintaining correct hydration, to prevent the formation of surface crusts.
5) Nutritional characteristics
The average nutritional profile of Made in Italy vaccine mozzarella is characterized as follows:
– proteins (mainly caseins), approximately 20%.
– fats, mostly saturated, approximately 20%.
– carbohydrates, mainly lactose, almost (but not entirely) absent. They are also made ‘lactose-free’ mozzarella, for consumers who are intolerant to it
– mineral salts. Mozzarella is a good source of sodium, calcium and phosphorus. It also contains potassium and iron, albeit in lower quantities
– vitamins. There are appreciable levels of riboflavin (vit B2) and vitamin A, as well as niacin (vit B3), thiamine (vit B1) and vitamin E. (6)
Francesco Carlini
Footnotes
(1) Silvia Bonardi, Dario Dongo. Malga cheeses and fresh raw milk cheeses, the STEC danger . GIFT (Great Italian Food Trade).
(2) EFSA. Drinking raw milk: what are the risks? https://www.efsa.europa.eu/it/press/news/150113
(3) Dario Dongo, Michele Polignieri. Mozzarella, here’s why to be wary of citric acid . GIFT (Great Italian Food Trade). 6.11.20
(4) L. de Ruvo. Curd stretching: can be considered a control measure https://arclab.it/la-filatura-della-cagliata-si-puo-considerare-come-una-misura-di-controllo/
(5) G. Mucchetti and E. Neviani. Dairy microbiology and technology. Tecniche Nuove, Milan, 2006. ISBN 978-88-481-1817-0
(6) Italian Society of Human Nutrition (2014). LARN, Reference Intake Levels of Nutrients and Energy for the Italian Population, IV Revision https://sinu.it/tabelle-larn-2014/
