A Co-Association of Streptococcus mutans and Veillonella parvula/dispar in Root Caries Patients and In Vitro Biofilms.

Root caries in geriatric patients is a growing problem as more people are maintaining their natural teeth into advanced age. We determined the levels of various bacterial species previously implicated in root caries disease or health using quantitative real-time PCR in a pilot study of 7 patients with 1 to 4 root caries lesions per person. Levels of 12 different species on diseased roots compared to healthy (contralateral control) roots were measured. Four species were found at significantly higher levels on diseased roots (Streptococcus mutans, Veillonella parvula/dispar, Actinomyces naeslundii/viscosus, and Capnocytophaga granulosa) compared across all plaque samples. The level of colonization by these species varied dramatically (up to 1,000-fold) between patients, indicating different patients have different bacteria contributing to root caries disease. Neither of the two species previously reported to correlate with healthy roots (C. granulosa and Delftia acidovorans) showed statistically significant protective roles in our population, although D. acidovorans showed a trend toward higher levels on healthy teeth (P = 0.08). There was a significant positive correlation between higher levels of S. mutans and V. parvula/dispar on the same diseased teeth. In vitro mixed biofilm studies demonstrated that co-culturing S. mutans and V. parvula leads to a 50 to 150% increase in sucrose-dependent biofilm mass compared to S. mutans alone, depending on the growth conditions, while V. parvula alone did not form in vitro biofilms. The presence of V. parvula also decreased the acidification of S. mutans biofilms when grown in artificial saliva and enhanced the health of mixed biofilms.

Quality assessment of lemon (Citrus aurantifolia, swingle) coated with self-healed multilayer films based on chitosan/carboxymethyl cellulose under cold storage conditions.

The polyelectrolyte multilayer self-healing coating film of chitosan and carboxymethyl cellulose (PEM-SH) tended to maintain high sensory quality and control physiological and pathological decay of lemon fruits under cold storage. The PEM-SH film was characterized by ATR-IR, XRD, X-ray photoelectron spectroscopy, SEM analysis, swelling ratio, self-healing, and mechanical characteristics. The 3-layered film (3L) exhibited the optimum barrier properties; WVP: 3.32 ± 0.06 g. mm. k Pa-1.h-1.m-2 and GTR: 0.256 ± 0.032 cc.M-2.day-1. The moisture sorption isotherm data were fitted with BET, GAB, and Peleg models and three models showed applicability. The coated fruits exhibit superior features of fruit quality such as reduced weight loss %, respiration rate, and decay symptoms appearance. The 3L-coated fruit showed the lower pectinase enzyme activity (0.689 Ug-1 FW) up to 60 days. As well as, increased total soluble solids, keeping vitamin C of loss and decreasing percentage acidity of juice up to 60 days.

Smart edible coating films based on chitosan and beeswax-pollen grains for the postharvest preservation of Le Conte pear.

Smart edible coating films can be used in food packaging. For this application, they must have good physical and mechanical properties. Herein, chitosan-beeswax based film is used to preserve Le Conte pears postharvest. The chitosan-beeswax films were characterized using XRD, FT-IR, and SEM analysis. Moreover, all films showed good self-healing aptitudes ranging from 86.7 to 96.3. The film treated with pollen grains showed an enhanced water contact angle compared with the chitosan film. The chitosan-beeswax/pollen grain film exhibited a two-fold lower WVTR value compared to the chitosan film, and showed the tendency to increase the stiffness of the film. The elongation% at break was reduced from 35.81 to 14.09. Fruit quality parameters were determined in cold storage for 105 days during shelf life after a simulated marketing period of 7 days. All coated fruits successfully showed decrease in weight loss, decay and rate of softening. Therefore, chitosan-beeswax/pollen grains can be considered safe and effective coating for the fruit preservation.