Peruzy Maria Francesca, Blaiotta Giuseppe, Aponte Maria, De Sena Maria, Murru Nicoletta
Department of Veterinary Medicine and Animal Production.
Department of Agricultural Sciences.
Ital J Food Saf. 2022 Jun 27;11(2):10162. doi: 10.4081/ijfs.2022.10162. eCollection 2022 Jun 21.
"Grottone" is a pasta filata hard cheese produced in Campania region from cow's milk and characterized by holes formation due to CO development by Propionic Acid Bacteria. The contamination of raw milk with butyric acid-producing spore-forming clostridia represent a major concern for cheese producers since clostridia outgrowth may lead to the cheese late blowing defect during ripening. Detection of clostridial endospores in milk before processing and the use of antimicrobial compounds may represent an important control strategy. The present study is aimed to point out the most suitable procedure for the determination of clostridial spores in dairy samples, and to assess the inhibitory activity of several antimicrobial compounds against . Based on results, MPN counts on Bryant and Burkey medium and CFU on RCM proved to be the most suitable protocols for routine testing. By using these procedures clostridial spores were detected in 10 out 13 milk samples and in all cheeses with late blowing defect. Within antimicrobial compounds, sodium nitrate is still the best choice for preventing late blowing, nevertheless a protective culture of proved to be a promising alternative. Nevertheless, the use of this protective culture in six Grottone cheese productions carried out at farm level, led to unsatisfactory results. Holes' development was hampered likely for an inhibition of the PAB starter and the expected 'Grouviera-type' taste was not perceived by panellists. Based on results, the use of protective cultures needs to be contextualized and interactions with starters needs to be evaluated case by case.
“格罗托内”是一种在坎帕尼亚地区用牛奶生产的丝状硬质干酪，其特点是由于丙酸菌产生二氧化碳而形成气孔。生牛奶被产丁酸芽孢梭菌污染是奶酪生产商主要关注的问题，因为芽孢梭菌的生长可能导致奶酪在成熟过程中出现后期产气缺陷。在加工前检测牛奶中的梭菌芽孢以及使用抗菌化合物可能是一种重要的控制策略。本研究旨在指出测定乳制品样品中梭菌芽孢的最合适方法，并评估几种抗菌化合物对……的抑制活性。根据结果，在布莱恩特和伯基培养基上进行的最大可能数计数以及在强化梭菌培养基上的菌落形成单位计数被证明是常规检测最合适的方案。通过使用这些方法，在13份牛奶样品中的10份以及所有有后期产气缺陷的奶酪中检测到了梭菌芽孢。在抗菌化合物中，硝酸钠仍然是防止后期产气的最佳选择，然而，……的保护性培养物被证明是一种有前景的替代方法。然而，在农场层面进行的6次格罗托内奶酪生产中使用这种保护性培养物，结果并不理想。气孔的形成可能受到了抑制，这可能是由于对丙酸菌发酵剂的抑制，而且品评员没有察觉到预期的“格鲁维耶拉型”风味。根据结果，保护性培养物的使用需要结合具体情况，并且需要逐案评估与发酵剂的相互作用。
