# Ready-to-Use Vegetable Salads: Physicochemical and Microbiological Evaluation
## 3 Results and Discussion
The high content of nitrites can be due to cultivation conditions (use of fertilizers containing nitrates and then the conversion of nitrates into nitrites under the action of microorganisms under certain conditions), processing (washing), packaging and storage. Nitrites are considered to be potentially harmful, but the concentration of nitrites in vegetables is not currently subject to any regulatory limitations [16]. The ADI for nitrites is between 0 and 0.07 mg/kg body weight/day, according to the European Food Safety Authority [45]. The ADI for nitrites corresponds to 4.2 mg for a person of 60 kg per day [16]; therefore, the ingestion of 100 g of \"Oak leaf\" lettuce (sample 1P) with a nitrite concentration of 876 mg/kg will result in an intake of 87.6 mg nitrite, which far exceeds the ADI. The results of this study indicated that for all investigated ready-to-use vegetable salad samples, the nitrite intake would far exceed the ADI. The impacts of nitrite (negative and positive) on human health are still under discussion. According to [PERSON] et al. [46], the clear cardiovascular benefits of dietary nitrite may outweigh the potential risks, but there are also studies connecting the consumption of nitrite-rich foods with diabetes [16]. Ready-to-use vegetable salad samples were characterized by different microbiological qualities. Figure 4 illustrates the presence of the total number of germs, _Staphylococci_, _Enterobacteriaceae_, _Salmonella_ and total coliforms on different samples. Figure 4: Total number of germs present on coded samples: (**a**) 2A; (**b**) 1P; (**c**) _Staphylococci_ present on 4K-coded lettuce; (**d**) _Enterobacteriaceae_ present on coded lettuce 3L; (**e**) _Salmonella_ present on 5L sample; and (**f**) total coliforms present on 5L sample. There are no microbiological criteria set for ready-to-use foods in the EU. Only Commission Regulation 1441/2007, formerly Commission Regulation 2073/2005, is applicable [47; 48] for pre-cut fruit and vegetables (ready-to-use): for _Salmonella_, an absence in 25 g, and for _E. coli_, 1000 CFU/g. The total viable count of microorganisms is not a legislative criterion for ready-to-use vegetable salads, but it is an important indicator of sensory and hygiic quality [3]. The TNGs ranged from 5.42 log CFU/g (sample 3L) to 8.12 log CFU/g (sample 3A), while yeasts and molds were mainly observed in groups L and K samples, with the lowest values for samples 4L (2.67 log CFU/g) and 4K (2.77 log CFU/g), and the highest values for samples 5L (5.48 log CFU/g) and 5K (5.17 log CFU/g) (Table 3). The number of yeasts and molds was lower than the number of the TNGs. Also, the number of yeasts and molds are similar to those reported by [PERSON] et al. [3] (1.0-7.0 log CFU/g ready-to-use salads), [PERSON] et al. [49] (6.2-7.5 log CFU/g for ready-to-use salads and 5.4-7.6 log CFU/g for fresh-cut vegetables) and [PERSON] et al. [50] (5.0-7.0 log CFU/g for packed ready-to-use vegetables). _Staphylococci_ were present only in the 4L sample (2.67 log CFU/g), and in the K group samples, they ranged from 1.33 log CFU/g (1K sample) to 5.97 log CFU/g (4K sample). High numbers of _Enterobacteriaceae_ (EB) were found in samples from groups A (6.04-6.56 log CFU/g) and P (6.20-6.33 log CFU/g), which means a high degree of microbiological contamination (higher than 6 log CFU/g) [3], while total coliforms were present in all ready-to-use vegetable samples, with numbers between 5.00 log CFU/g (sample 1P) and 6.39 log CFU/g (sample 1K). [PERSON] et al. [49] reported that the number of total coliform in fresh-cut vegetables and ready-to-use salads was 4.0 log CFU/g. No _Faecal streptococci_ were present in any of the samples analyzed. _Listeria_ was found only in samples 3L (2.67 log CFU/g), 4L (4 log CFU/g), 2L and 5K (4.20 log CFU/g), and 4K (4.36 log CFU/g) (5 out 17 ready-to-use vegetable salads (29.4%)), while _Salmonella_ was detected only in sample 5L (4.90 log CFU/g) (1 out 17 ready-to-use vegetable salads (5.9%)). _Listeria_ was detected by [PERSON] et al.