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Recombinant DNA techniques are capable of introducing genetic changes into food organisms that are more predictable than those introduced through conventional breeding techniques. This review discusses whether the consumption of DNA in approved novel foods and novel food ingredients derived from genetically modified organisms (GMOs) can be regarded as being as safe as the consumption of DNA in existing foods. It concludes that DNA from GMOs is equivalent to DNA from existing food organisms that has always been consumed with human diets. Any risks associated with the consumption of DNA will remain, irrespective of its origin, because the body handles all DNA in the same way. The breakdown of DNA during food processing and passage through the gastrointestinal tract reduces the likelihood that intact genes capable of encoding foreign proteins will be transferred to gut microflora. The review does not specifically address food safety issues arising from the consumption of viable genetically modified microorganisms but it shows that the likelihood of transfer and functional integration of DNA from ingested food by gut microflora and/or human cells is minimal. Information reviewed does not indicate any safety concerns associated with the ingestion of DNA per se from GMOs resulting from the use of currently available recombinant DNA techniques in the food chain.

In a screening for proteolytically active lactic acid bacteria, three strains, Lactobacillus delbrueckii ssp. lactis 92202, Lactobacillus helveticus 92201, and Lactobacillus delbrueckii ssp. bulgaricus 92059, showed the highest activities following growth in milk. All three strains degraded α- and β-casein, but did not hydrolyse κ-casein. HPLC analysis of skim milk fermentation revealed increasing amounts of peptides after 5 and 10 h with Lb. d. ssp. bulgaricus 92059. Hydrolysates obtained with Lb. d. ssp. lactis 92202 and Lb. d. ssp. bulgaricus 92059 revealed the highest angiotensin-converting enzyme-inhibitory effect. The effect was dose dependent. Almost no effect (<10%) was seen for Lb. helveticus 92201. For Lb. d. ssp. bulgaricus 92059, maximal inhibition of approx. 65% was reached after 25 h of fermentation. In an in vitro assay measuring potential immunomodulation, hydrolysates of the three strains yielded anti-inflammatory activities in the presence of TNF-α. However, the effects were more pronounced at lower hydrolysate concentrations. In the absence of TNF-α, slight pro-inflammatory effects were observed. The hydrolysate of Lb. d. ssp. bulgaricus 92059, when purified by means of solid-phase extraction, exhibited pro-inflammatory activity. Sour whey containing Lb. d. ssp. bulgaricus 92059 cells showed pro-inflammatory activity while cell-free sour whey was clearly anti-inflammatory. In the purified hydrolysate, 20 different α- and β-casein (CN)-derived peptides could be identified by LC-MS. Most peptides originated from the central and C-terminal regions of β-casein. Peptide length was between 9 (β-CN(f 59–67)) and 22 amino acids (β-CN(f 117–138)).

The proteinase-encoding prtB gene of Lactobacillus ( Lb .) delbrueckii ( d. ) subsp. bulgaricus 92059 was cloned and sequenced. Two soluble, secreted, C-terminally His-tagged derivatives were constructed and expressed in Lactococcus lactis by means of the NICE® Expression System. In both obtained derivatives PrtBb and PrtB2, the C-terminal, cell wall-binding domain was deleted. In addition, in derivative PrtB2, the C-terminal part of the B domain was deleted and the signal sequence was replaced by a lactococcal export signal. The affinity-purified derivatives were both proteolytically active. Peptide hydrolysates produced from casein with each of the derivatives showed identical peptide composition, as determined by liquid chromatography–mass spectrometry. Comparison of the peptides generated to those generated with living Lb . d . subsp. bulgaricus 92059 cells (Kliche et al. Appl Microbiol Biotechnol 101:7621–7633, 2017 ) showed that β-casein was the casein fraction most susceptible to hydrolysis and that some significant differences were observed between the products obtained by either the derivatives or living Lb. d . subsp. bulgaricus 92059 cells. When tested for biological activity, the hydrolysate obtained with PrtBb showed 50% inhibition of angiotensin-converting enzyme at a concentration of 0.5 mg/ml and immunomodulation/anti-inflammation in an in vitro assay of TNF-α induced NFκB activation at concentrations of 5 and 2.5 mg/ml, respectively. The enzymatically obtained hydrolysate did not show any pro-inflammatory or cytotoxic activity.

Amplified Ribosomal-DNA Restriction Analysis (ARDRA) was used to differentiate among 12 species and 4 subspecies of the genus Staphylococcus. With a universal primer pair a 2.4 kbp PCR-product was amplified, including the 16S rDNA, the 16S-23S rDNA interspacer region, and about 500 bp of the 23S rDNA. Species-specific restriction patterns were found using the restriction enzymes Hin dIII and Xmn I separately. Cheese related staphylococci were clearly differentiated. ARDRA results were in good agreement with results of partial sequencing of the 16S rDNA. ARDRA could fully replace the biochemical identification with ID32 Staph (BioMerieux) which was less reliable when staphylococci of cheese origin were analysed. Genomic restriction digests of cheese-related S. equorum strains by Sma I and Sac I gave unique strain-specific restriction patterns which can be used to identify starter staphylococci in a complex microbial environment such as the surface of Red-Smear cheeses.

ARDRA (Amplified Ribosomal-DNA Restriction Analysis) was used to differentiate among species and genera of Arthrobacter and Microbacteria. Species-specific restriction patterns of PCR-products were obtained with Nci I for Arthrobacter citreus(DSM 20133 T), A. sulfureus(DSM 20167 T), A. globiformis(DSM 20124 T) and A. nicotianae strains (DSM 20123 T, MGE 10D, CA13, CA14, isolate 95293, 95294, and 95299), A. rhombi CCUG 38813 T, and CCUG 38812, and Microbacterium barkeri strains (DSM 30123 T, MGE 10D, CA12 and CA15, isolate 95292, and isolate 95207). All yellow pigmented coryneforme bacteria isolated from the smear of surface ripened cheeses were identified as either A. nicotianae or M. barkeri strains. Using pulsed field gel electrophoresis (PFGE) strain specific restriction pattern for all Arthrobacter species and Microbacteria tested were obtained with restriction enzymes Asc I and Spe I.

Coupled seismic and electromagnetic (EM) wave effects in fluid-saturated porous media are measured since decades. However, direct comparisons between theoretical seismoelectric wavefields and measurements are scarce. A seismoelectric full-waveform numerical model is developed, which predicts both the fluid pressure and the electric wavefields in a fluid in which a porous disc is embedded. An experimental setup, in which pressure and electric signals in the fluid are simultaneously measured, is presented. The setup allows the detection of the EM field that is generated when an acoustic wave crosses the interface between the fluid and the thin porous disc, without interference of electrical fields that are present within seismic body waves. The predicted pressure wavefield agrees well with the measurements in terms of acoustic wave travel times, waveforms, and amplitudes. The electric wavefield predictions agree with the recordings in terms of travel times, waveforms, and spatial amplitude decay. A discrepancy in amplitude of the converted EM signal is observed. Theoretical amplitudes that are smaller than the measurements were also reported in previous literature. These results seem to validate seismoelectric theory.

Transformation of naturally competent Bacillus subtilis with plasmid was carried out in chocolate milk without antibiotics. Transformed cells were enumerated during the entire growth phase in chocolate milk. When DNA was added to aliquots of a batch culture after different times of incubation, transformation events were detected at all different growth stages. When DNA was added to a batch culture together with the inoculum, transformed cells were detected at the onset of exponential growth. However, apparently no or only limited growth of these transformed cells was observed. To clarify, whether the limitation of growth was due to suppression by non-transformed cells, different proportions of B. subtilis cells either carrying or not carrying the plasmid were mixed and inoculated into chocolate milk without antibiotic. Our results indicate that suppression appears to be of minor importance. Instead, plasmid-bearing cells appear to suffer from a prolonged lag-phase. However, the failure to exhibit significant growth of cells which had taken up the plasmid in chocolate milk appears to be due to failure of these cells to establish themselves as permanently transformed under non-selective conditions.

In previous investigations, was shown to lack the metabolic pathway from fructose to mannitol and to produce ethanol when cultivated in the presence of fructose. Hence, we assessed the effect of oral administration of (strain NRRL-B-14171) on blood and fecal ethanol concentrations, glucose and lipid metabolism and traits of the metabolic syndrome in Wistar rats (n=27) fed diets with two different fat and fructose levels and with or without the addition of during a total intervention time of 15 weeks (105 days). From week 1 to 6, rats were given a medium fructose and fat (MFru-MF) diet containing 28% fructose and 10% fat without the addition of (control group, n=13) or mixed with 30 g per kg diet of lyophilized (10.56 ± 0.20 log CFU/g; group, n=14). From week 7 to 15, the percentage of dietary fructose and fat in the control and group was increased to 56% and 16%, respectively (high fructose-high fat (HFru-HF) diet). In HFru-HF-fed rats, was detected in feces, regardless of whether was added to the diet or not, but not in rats receiving the MFru-MF diet without added or in an additional control group (n=10) fed standard rat food without fructose, increased fat content and . This indicates that fecal may be derived from orally administered as well as - in the case of high fructose and fat intake and obesity of rats - from the intestinal microbiota. As shown by multifactorial ANOVA, blood ethanol, the relative liver weight, serum triglycerides, and serum cholesterol as well as fecal ethanol, ADH, acetate, propionate and butyrate, but not lactate, were significantly higher in the compared to the control group. This is the first in vivo trial demonstrating that heterofermentative lactic acid bacteria lacking the mannitol pathway (like ) can increase fecal and blood ethanol concentrations in mammals on a high fructose-high fat diet. This may explain why resulted in hyperlipidemia and may promote development of NAFLD in the host.