Antibacterial activity and sensory properties of Heracleum persicum essential oil, nisin, and Lactobacillus acidophilus against Listeria monocytogenes in cheese.

AIM: The aim of this study was to evaluate the antibacterial and chemical effect of Heracleum persicum essential oil (EO), nisin, Lactobacillus acidophilus, and their combination against Listeria monocytogenes both in vitro and in Iranian white cheese model. MATERIALS AND METHODS: Chemical compositions of H. persicum EO were analyzed by gas chromatography-mass spectrometry. After production of Iranian white cheese, minimum inhibitory concentration (MIC) and minimum bactericidal concentration of EO and nisin and agar spot test of L. acidophilus against L. monocytogenes were evaluated. RESULTS: Hexyl butanoate (25.98%), octyl isobutyrate (17.82%), methyl butyrate (14.37%), and pentyl cyclopropane (12.77%) were the main components of the EO. MIC of the EO against L. monocytogenes was 2.5 mg/mL. Combination of nisin (5.3 IU/mL) and H. persicum EO (2500 µg/mL) showed increasing effect against L. monocytogenes (fractional inhibitory concentration = 0.9), while a higher concentration of EO and nisin showed undesirable effect on the cheese flavor. Furthermore, a combination of 1012 CFU/g L. acidophilus with H. persicum EO at the concentration of 2.5 mg/mL (T12) showed acceptable sensorial and also antibacterial results in Iranian white cheese. CONCLUSION: Combination of H. persicum EO, L. acidophilus, and nisin can be recommended as natural preservatives and flavoring agents in cheese.

Probiotic white cheese production using coculture with Lactobacillus species isolated from traditional cheeses.

AIM: The aim of the present study was to investigate the viability of lactic acid bacteria isolated from traditional cheeses and cocultured in Iranian white cheese during ripening. MATERIALS AND METHODS: A total of 24 samples were isolated from 8 types of traditional cheeses in West Azerbaijan, Iran. Isolated species were cocultured with starter bacteria during the production of Iranian white cheese, and their viability was investigated up to 60 days of the refrigerated storage. RESULTS: Of 118 isolates of Lactobacillus, 73 isolates (62%) were confirmed as facultative heterofermentative and 45 isolates (38%) as obligate homofermentative. Of the facultative heterofermentatives, 28 isolates (24%) were Lactobacillus plantarum, 24 isolates (20%) were Lactobacillus casei, and 21 isolates (18%) were Lactobacillus agilis. Obligate homofermentatives were Lactobacillus delbrueckii (21%), Lactobacillus helveticus (14%), and Lactobacillus salivarius (3%). L. plantarum, L. casei and L. helveticus were found in high enough levels(106 CFU/g). CONCLUSION: According to the obtained data, it is recommended that complex starters such as L. helveticus, L. plantarum, and L. casei can be used in industrial productions of cheese to obtain exclusive properties of traditional cheeses.