Impact of bacteriocins from Lactococcus lactis CRL1109 and citric acid on the microbiological, physicochemical and sensory qualities of minimally processed vegetables

The increasing demand for fresh vegetables and for convenience foods is causing an expansion of minimally processed vegetables (MPV) market. The MPV industry is constantly looking for new technologies to maintain quality and for inhibit undesired microbial growth along the production chain. Biopreservation is considered a promising strategy to reduce the chemical preservatives use. In this work, the individual effect of the bacteriocin Bac1109, produced by Lactococcus lactis CRL1109, and citric acid (C. acid) in minimally processed carrots and purple cabbage stored at 4 degrees C for 12 d in aerobic packaging (AP) and modified atmosphere packaging (MAP) was evaluated. A significant reduction of the spoilage microorganism growth (Leuconostoc mesenteroides CRL950) and total viable cell count was achieved with the Bac1109 addition in the MPV after 12 d of storage. This treatment delayed respiratory activity, reduced the loss of carotenoid, chlorophyll and total phenolic content, and did not cause drastic changes in pH or colorimetric parameters. The addition of C. acid to the MPV reduced the loss of pigments, phenolic compounds and delayed the rate of respiration of vegetables; however, this treatment did not exert an effective microbiological control, producing unacceptable sensory changes. The samples treated with Bac1109 in AP were the most accepted by consumers, showing the highest scores in each tested attribute. The use of Bac1109 could represent a natural alternative to replace chemical additives as a vegetable biopreservative, leading to a balance between the demand for safe products and their physico-chemical and sensorial conservation.

Automated summary

Adding lactococcus lactis and citric acid to minimally processed vegetables can effectively inhibit microbial growth and maintain quality, but citric acid may cause sensory changes.