**8. Conclusions**

Lactic acid fermentation represents the easiest and most suitable way to increase daily consumption of nearly fresh fruits and vegetables. The health and safety of the products can be aided by the development of starter cultures. Progress in the field of antimicrobial LAB strains with multi-functional properties, including the degradation of mycotoxins, can be engineered to significantly improve the quality, safety and acceptability of plant foods.

Tomato processing resulted in several important changes in carotenoid concentration and lycopene isomer profile. Treatment with LAB breaks down the tomato cell matrix and makes carotenoids more available, yielding a higher level of total carotenoids. Moreover, tomatoes subjected to lactic acid fermentation results in high lycopene bioavailability accompanied by increased *cis*-lycopene content. According to our results, *P. pentosaceus* and *L. sakei* may be useful for the preservation of tomatoes. Such products could be recommended as being more biologically accessible with higher functional value.

The results of our tomato product colour analysis offered the possibility of evaluating the level of lycopene using the yellow colour characteristic of tomato products; this method was reproducible and accurate enough to substitute for the chemical extraction determinations and may be a useful tool for the tomato industry.

The direct use of *Pediococcus pentosaceus* KTU05-9 and *Lactobacillus sakei* KTU05-6 for tomato product fermentation increases the carotenoid content in tomato products, which is a beneficial additive that improves the colour, functional value and acceptability of ready-to-cook minced meat products. Ready-to-cook minced meat products that have been enriched with carote‐ noids, which lend good sensory quality and are produced to contain a high level of lycopene and ß-carotene, can increase the intake of carotenoids in the diet. This is the first time that selected lactobacilli-fermented tomato products have been used as source of lycopene and ßcarotene for food, and more research is needed to explain the mechanism of carotenoid increase in fermented tomato products.

All the tested LAB produced a mixture of L- and D-lactic acid, with the latter isomer at a lower level. Because of the potential toxicity of D-lactic acid in food, we report that the tomato products prepared using pure cultures of tested LAB were found in all cases to be safer than those treated by spontaneous fermentation.
