Effect of a new sustainable cooling system used during firming and brining on the microbiological, chemical, and sensory characteristics of buffalo mozzarella cheese.

The cooling applied during the firming and brining processes represents an important production step in mozzarella cheese-making. The temperature fluctuations of the cooling water can negatively affect the hygiene, composition, and quality of mozzarella. Some sustainable cooling systems can minimize this problem by using hot process fluids as heat sources to generate refrigerated energy. This study aimed to evaluate the effects of a new cooling system equipped with a water-ammonia absorption chiller (MA) on the characteristics of buffalo mozzarella through a comparative study with products cooled with a traditional ice water chiller (MT). The buffalo mozzarella cheese manufacture was monitored, and the samples were analyzed for chemical, nutritional, microbiological, and sensory characteristics. The MT samples showed an overall weight loss of 7.4% compared to an average of 2.8% for the MA samples. The MT samples were characterized by greater sapidity than the MA ones, which instead showed a higher moisture content that increased juiciness. The microbiological analysis showed a lower concentration of mesophilic bacterial load in the MA samples than in the MT ones [difference of 1 Log (CFU/g)], which is probably due to the low and constant temperatures that reduced the permanence time of the mozzarella in the vats (firming and brining). This study represents a preliminary positive evaluation of the use of this sustainable cooling system for mozzarella cheese, which is useful for dairy plants with an annual cheese production volume sufficient to justify the operating cost of the plant and the annual energy cost.

Phenotypic Antimicrobial Resistance Profile of Isolates Causing Clinical Mastitis in Dairy Animals.

Mastitis is the most frequent and costly disease of lactating animals and is associated with a significant reduction in milk yield, increased cost and culling. Early and specific antibiotic based treatment reduces the severity of the disease. Over the years the extensive use of antimicrobials has led to increase antimicrobial resistance. The present study was designed to investigate the prevalence of microorganisms responsible for mastitis and their antimicrobial resistance pattern. A total of 282 milk samples were collected from different animal species (sheep, cows and goats) with clinical mastitis. Antimicrobial resistance was evaluated for Streptococcus spp. and Staphylococcus spp. In cow samples Streptococcus spp. represented the most frequently isolated genus (33.84%), while Staphylococcus spp. was the most prevalent genus in sheep and goat samples (44.4 and 73.86%, respectively). Gentamicin and chloramphenicol were found to be the most effective drugs against the tested isolates, while the highest resistance rates were observed for amoxicillin, ampicillin, tetracycline, trimethoprim-sulfamethoxazole.

Use of Sonoelastography to Evaluate Texture Modifications of Mozzarella di Bufala Campana Protected Designation of Origin During Storage at Different Temperatures.

Mozzarella cheese from buffalo milk is a fresh, stringy-textured dairy product, exhibiting a porcelain white colour, a smooth, bright, and humid surface, an extremely thin rind and delicate taste. The high humidity typical of this cheese reduces its shelf-life and it is cause of dramatic organoleptic changes during storage. In this study we tested sonoelastography to evaluate texture changes of mozzarella cheese from buffalo milk during storage. Cheeses form local market produced in the same condition were divided in three batches and stored in different conditions: the first (B1) was stored in preserving liquid at room temperature (20°C); the second (B2) was stored without preserving liquid at 4°C; and the third (B3) was stored at 4°C in preserving liquid. In B1 sonoelastography showed a reduction of the hardness and stiffness of rind, while in B2 inelastic tissue increased its thickness. Best results were obtained in B3, where no significant difference was evidenced during storage.