title: Stability, antimicrobial activity, and effect of nisin on the physico-chemical properties of fruit juices.
abstract: Heat processing is the most commonly used hurdle for inactivating microorganisms in fruit juices. However, this preservation method could interfere with the organoleptic characteristics of the product. Alternative methods have been proposed and bacteriocins such as nisin are potential candidates. However, the approval of bacteriocins as food additives is limited, especially in foods from vegetal origin. We aimed to verify the stability, the effect on physico-chemical properties, and the antimicrobial activity of nisin in different fruit juices. Nisin remained stable in fruit juices (cashew, soursop, peach, mango, passion fruit, orange, guava, and cupuassu) for at least 30 days at room or refrigerated temperature and did not cause any significant alterations in the physico-chemical characteristics of the juices. Besides, nisin favored the preservation of vitamin C content in juices. The antimicrobial activity of nisin was tested against Alicyclobacillus acidoterrestris, Bacillus cereus, Staphylococcus aureus and Listeria monocytogenes in cashew, soursop, peach, and mango juices. Nisin caused a 4-log reduction in viable cells of A. acidoterrestris in soursop, peach, and mango juices after 8h of incubation, and no viable cells were detected in cashew juices. After 24h of incubation in the presence of nisin, no viable cells were detected, independently of the juices. To S. aureus, at 24h of incubation in the presence of nisin, viable cells were only detected in mango juices, representing a 4-log decrease as compared with the control treatment. The number of viable cells of B. cereus at 24h of incubation in the presence of nisin represented at least a 4-log decrease compared to the control treatment. When the antimicrobial activity of nisin was tested against L. monocytogenes in cashew and soursop juices, no reduction in the viable cell number was observed compared to the control treatment after 24h of incubation. Viable cells were four and six times less than in the control treatment, in peach and mango juices respectively. The most sensitive microorganism to nisin was A. acidoterrestris and the least sensitive was L. monocytogenes. Still, a reduction of up to 90% of viable cells was observed in peach and mango juices inoculated with L. monocytogenes. These results indicate that the use of nisin could be an alternative in fruit juice processing.
authors.affiliation: Departamento de Nutrição,Universidade Federal de Sergipe, São Cristóvão, Sergipe, Brazil.
authors.forename: Adelson Alves
authors.initials: AA
authors.lastname: de Oliveira Junior
authors.affiliation: Departamento de Tecnologia de Alimentos, Universidade Federal de Sergipe, São Cristóvão, Sergipe, Brazil.
authors.forename: Hyrla Grazielle Silva
authors.initials: HG
authors.lastname: de Araújo Couto
authors.affiliation: Departamento de Morfologia, Universidade Federal de Sergipe, São Cristóvão, Sergipe, Brazil. Electronic address: ana.barbosaufs@yahoo.com.br.
authors.forename: Ana Andréa Teixeira
authors.initials: AA
authors.lastname: Barbosa
authors.affiliation: Departamento de Tecnologia de Alimentos, Universidade Federal de Sergipe, São Cristóvão, Sergipe, Brazil.
authors.forename: Marcelo Augusto Guitierrez
authors.initials: MA
authors.lastname: Carnelossi
authors.affiliation: Departamento de Morfologia, Universidade Federal de Sergipe, São Cristóvão, Sergipe, Brazil.
authors.forename: Tatiana Rodrigues
authors.initials: TR
authors.lastname: de Moura
mesh_terms: D056450:Alicyclobacillus / Q000187:drug effects; D000900:Anti-Bacterial Agents / Q000737:chemistry* / Q000494:pharmacology; D001409:Bacillus cereus / Q000187:drug effects; D032084:Citrus sinensis / Q000737:chemistry; D005520:Food Preservatives / Q000737:chemistry* / Q000494:pharmacology; D000067030:Fruit and Vegetable Juices / Q000032:analysis* / Q000382:microbiology; D008089:Listeria monocytogenes / Q000187:drug effects; D031022:Mangifera / Q000737:chemistry; D009561:Nisin / Q000737:chemistry* / Q000494:pharmacology; D013211:Staphylococcus aureus / Q000187:drug effects
chemical_list: D000900:Anti-Bacterial Agents; D005520:Food Preservatives; D009561:Nisin; C102526:nisin A
keywords: Alicyclobacillus acidoterrestris; Bacteriocin; Food preservation; Listeria monocytogenes; Microbial inactivation