The use of mozzarella extends well beyond pizza toppings. Buffalo
mozzarella from Campania is a distinctive Italian cheese that has been
declared a delicacy and is protected by EU legislation for almost 30 years.
What, though, makes this mozzarella so unique? The components are
straightforward: fresh water and brine were used to process the water
buffalo milk, rennet, and natural whey starter.
However, the natural whey starter has microorganisms that are essential for
producing mozzarella. High-throughput 16S rRNA amplicon sequencing, which
provides a thorough image of what microorganisms are present and in what
proportions, was employed by Italian researchers to gain an understanding of
how microbes produce mozzarella.
Dr. Alessia Levante of the University of Parma, the study's lead author,
said, "This study fosters a deeper understanding of the craftsmanship behind
this esteemed Italian cheese and sheds light on the intricate interactions
of microorganisms throughout the manufacturing process."
Under the microscope, mozzarella
Buffalo mozzarella must be produced in accordance with a precise formula to
be eligible for protected designation of origin (PDO) certification. Heat,
rennet, and natural whey starter are added to heated raw or pasteurized
water buffalo milk. With the help of this starter, the curd soon becomes
acidified, reaching the proper pH and becoming elastic enough to be
shaped.
The resulting curds are allowed to mature for around four hours until they
reach the proper pH level, at which point they become elastic and may be
stretched and shaped in boiling water. The curds are then brined and
hardened under running water. This process, with a few minor modifications,
distinguishes between the products of various dairy farms.
Levante and her team chose two dairies in Campania that produce mozzarella
that is eligible for PDO status: one larger and using more modern
technology, and one smaller and using more traditional processes. They did
this to examine the role of bacteria and see if it differs between
traditional dairies and more modern ones. They sampled the milk, natural
whey starter, curds before stretching, brine, and mozzarella from the
dairies.
While both farms produced PDO mozzarella di bufala Campana, there were
slight differences in the cheese's microbiological makeup and possible
organoleptic qualities due to factors including temperature and processing
time, according to Levante.
Bacteria take action and order a pizza.
The concentration of 19 samples was sufficient for 16S rRNA amplicon gene
sequencing. This method identifies the microorganism species present and the
amounts they occur in by sequencing the DNA of a sample and amplifying
certain sections of a highly variable gene.
The researchers discovered that although the more traditional dairy
utilized thermized milk, which introduced more bacteria and species to the
process, the more contemporary dairy used pasteurized milk. However, the
brine samples were just as rich in species as the processed cheese samples.
During the curd-making process, a few species emerge and take control.
Microorganisms from the Lactobacillus and Streptococcus genera dominated
both samples. While the more contemporary dairy employed a natural whey
starting dominated by Streptococcus, the more traditional dairy's starter
had nearly equal amounts of both. Each genus had species that were unique to
that dairy. After curdling, Lactobacillus rises and Streptococcus falls in
both sets of samples, probably as a result of the removal of the heat stress
brought on by the stretching procedure.
Additionally, the brine provides a source of microbial variety by
introducing fresh bacteria to the cheese's outer layer when it comes into
contact with it. Not all of the bacteria in the brine, nevertheless,
transfer to the cheese. This could be the case either because they cannot
survive on cheese or because they appear later in the cheese's shelf life,
after the cheese samples were obtained. Despite the enormous variety of
microbe species present in the milk and brine, it appears that the natural
whey starter has the greatest impact on the microbial composition of
mozzarella.
Levante stated, "We are preparing a larger experiment to explore more
thoroughly the function of raw buffalo milk in defining the microbiota. The
scope of this investigation was constrained to two dairies and a certain
sample size. Future research seeks to include a greater number of producers
and manufacturing days to give more thorough insights into the
microbiological complexities of traditional food production.
Provided by
Frontiers
