The application of a fermented food ingredient containing ‘variacin’, a novel antimicrobial produced byKocuria varians, to control the growth ofBacillus cereusin chilled dairy products

Abstract

Aims: The feasibility of applying variacin, a lantibiotic produced by Kocuria varians in the form of a spray-dried fermented ingredient to control the growth of psychrotrophic Bacillus cereus strains in chilled dairy foods, was evaluated. Methods and Results: A range of chilled dairy food formulations modelling commerciallyavailable products were fabricated, to which were added varying amounts of active ingredient. These were subsequently challenged with a B. cereus spore cocktail over a range of abuse temperatures. This work was validated by the inclusion of the fermented ingredient to commercial products. Conclusions: Results demonstrate the functionality of the bacteriocin at refrigeration abuse temperatures, and indicate the robust nature of the proteinaceous antimicrobial agent with regard to processing. Signi®cance and Impact of the Study: This study indicates the applicability of fermented food ingredients containing naturally-occurring antimicrobials as additional hurdles in food preservation.

The role of antibiosis in the antagonism of different bacteria towards Helminthosporium solani, the causal agent of potato silver scurf

“…Although B. mycoides (Papou and Gryn`ko 1994), K. varians (Molet et al 2004;O'Mahony et al 2001) and Rhodococcus sp. (Hiroyuki et al 1999) had previously been shown to produce antibiotics, no antibiosis could be revealed with these species against H. solani in this study.…”

Lantibiotics produced by Actinobacteria and their potential applications (a review)

“…At 12 C, the addition of 3 % fermented ingredient was required to inhibit outgrowth of the spores [53]. However, further studies, such as (i) tests of the variacin cytotoxicity to eukaryotic cells at the concentrations used in the study of O'Mahony and coworkers, (ii) the effectiveness of the bacteriocin in other food matrices and (iii) other bacteriocin properties (such as shelf-life and sensitivity to gastrointestinal conditions), should be encouraged so the feasibility of using this lantibiotic as a natural antimicrobial to control undesirable micro-organisms in food products is confirmed.…”

Semi-preparative scale purification of enterococcal bacteriocin enterocin EJ97, and evaluation of substrates for its production

“…Alternatively, commercial bacteriocin preparations can be added onto the foods. In order to meet the complex nutritional requirements of LAB and lower the production costs, cheap substrates such as whey, potato waste as well as mussel or Wsh-processing wastes has been tested for production [2,12,20,21,23,25,31,33,36,37]. Standardization of the optimal conditions for bacteriocin production and recovery are therefore key factors to be determined before doing Weld studies for bacteriocin application, and several studies to optimise production of the bacteriocins nisin, pediocin PA1/AcH, AS-48 and many others have been carried out [1,4,5,37].…”

“…Standardization of the optimal conditions for bacteriocin production and recovery are therefore key factors to be determined before doing Weld studies for bacteriocin application, and several studies to optimise production of the bacteriocins nisin, pediocin PA1/AcH, AS-48 and many others have been carried out [1,4,5,37]. Food-grade lyophilized preparations of crude or partially-puriWed bacteriocins such as nisin, pediocin PA1/AcH, lacticin 3147 and variacin are available [12,25,26,31,33]. However, low production yields and diYculties in obtaining signiWcant amounts of pure bacteriocin have limited, in part, the biochemical and physical characterization of the active compounds in many cases [3].…”