The antimicrobial activity of carvacrol, a compound present in the essential oil fraction of oreganum and thyme, toward the foodborne pathogen Bacillus cereus on rice was studied. Carvacrol showed a dose-related inhibition of growth of the pathogen. Concentrations of 0.15 mg/g and higher inhibited the growth and the extent of inhibition depended on the initial inoculum size. To decrease the input of carvacrol on the taste and flavor of the product, a combined treatment with the structure analog cymene was tested. Due to the smell and taste of carvacrol at high concentrations, carvacrol was combined with cymene, a natural antimicrobial compound with a similar structure. A synergistic effect was observed when 0.30 mg/g carvacrol was combined with 0.27 mg/g cymene. Finally it was demonstrated that a common taste enhancer like soya sauce also increased the antimicrobial action of carvacrol toward B. cereus. The antimicrobial activity of carvacrol with cymene or soya sauce was influenced by the addition of NaCl.

The impact of high O 2 + high CO 2 modified atmospheres (MA), on the preservation of minimally processed carrots was studied. A combination of 50% O 2 + 30% CO 2 prolonged the shelf life of sliced carrots compared to storage in air by 2 to 3 d. When the carrots received a pre-treatment with a 0.1% citric acid dip and a sodium alginate edible coating prior to packaging, shelf life was extended by 5 to 7 d. Advantages and disadvantages of the proposed MA over previously recommended MA (1% O 2 + 10% CO 2 ), related to a range of physicochemical and microbiological characteristics of carrots are discussed.

Background Altered gut microbiota is implicated in cow’s milk allergy (CMA) and differs markedly from healthy, breastfed infants. Infants who suffer from severe CMA often rely on cow’s milk protein avoidance and, when breastfeeding is not possible, on specialised infant formulas such as amino-acid based formulas (AAF). Herein, we report the effects of an AAF including specific synbiotics on oral and gastrointestinal microbiota of infants with non-IgE mediated CMA with reference to healthy, breastfed infants. Methods In this prospective, randomized, double-blind controlled study, infants with suspected non-IgE mediated CMA received test or control formula. Test formula was AAF with synbiotics (prebiotic fructo-oligosaccharides and probiotic Bifidobacterium breve M-16V). Control formula was AAF without synbiotics. Healthy, breastfed infants were used as a separate reference group (HBR). Bacterial compositions of faecal and salivary samples were analysed by 16S rRNA-gene sequencing. Faecal analysis was complemented with the analysis of pH, short-chain fatty acids (SCFAs) and lactic acids. Results The trial included 35 test subjects, 36 controls, and 51 HBR. The 16S rRNA-gene sequencing revealed moderate effects of test formula on oral microbiota. In contrast, the gut microbiota was substantially affected across time comparing test with control. In both groups bacterial diversity increased over time but was characterised by a more gradual increment in test compared to control. Compositionally this reflected an enhancement of Bifidobacterium spp. and Veillonella sp. in the test group. In contrast, the control-fed infants showed increased abundance of adult-like species, mainly within the Lachnospiraceae family, as well as within the Ruminococcus and Alistipes genus. The effects on Bifidobacterium spp. and Lachnospiraceae spp. were previously confirmed through enumeration by fluorescent in situ hybridization and were shown for test to approximate the proportions observed in the HBR. Additionally, microbial activity was affected as evidenced by an increase of l -lactate, a decrease of valerate, and reduced concentrations of branched-chain SCFAs in test versus control. Conclusions The AAF including specific synbiotics effectively modulates the gut microbiota and its metabolic activity in non-IgE mediated CMA infants bringing it close to a healthy breastfed profile. Trial registration Registered on 1 May 2013 with Netherlands Trial Register Number NTR3979.

We aimed to determine the effects of enteral supplementation of a prebiotic mixture of neutral and acidic oligosaccharides (scGOS/lcFOS/pAOS) on the faecal microbiota and microenvironment in preterm infants. Furthermore, we determined the influence of perinatal factors on the development of the faecal microbiota. In a randomised controlled trial, preterm infants with gestational age <32 weeks and/or birth weight <1,500 g received enteral supplementation of scGOS/lcFOS/pAOS or placebo (maltodextrin) between days 3 and 30 of life. Faecal microbiota, as measured with fluorescent in situ hybridisation (FISH), and microenvironment [short-chain fatty acids (SCFAs), pH, sIgA] were measured at four time points: before the start of the study and at days 7, 14 and 30 of life. In total, 113 preterm infants were included. Enteral supplementation of the prebiotic mixture increased the total bacteria count at day 14 (Exp 3.92; 95 % confidence interval [CI] 1.18-13.04, p = 0.03), but not at day 30 (Exp 1.73; 95 % CI 0.60-5.03, p = 0.31). There was a trend toward increased bifidobacteria counts. There was a delayed intestinal colonisation of all bacteria. Enteral supplementation of the prebiotic mixture decreased the faecal pH (Exp 0.71; 95 % CI 0.54-0.93, p = 0.01) and there was a trend toward increased acetic acid compared to the placebo group (Exp 1.09; 95 % CI 0.99-1.20, p = 0.10). There was no effect on sIgA (Exp 1.94; 95 % CI 0.28-13.27, p = 0.50). Antibiotics decreased the total bacteria count (Exp 0.13; 95 % CI 0.08-0.22, p < 0.001). Enteral supplementation of a prebiotic mixture of neutral and acidic oligosaccharides increases the postnatal intestinal colonisation. However, the extensive use of broad-spectrum antibiotics in preterm infants decreased the growth of all intestinal microbiota, thereby, delaying the normal microbiota development.