To determine differences in quality parameters between different types of tea elaborated in Argentina, water extract, crude fibre, caffeine, total polyphenol content, antioxidant activity, sorption isotherms and colour parameters (L, a, b) were determined. Fifty-one industrial samples of commercially available teas including green tea, semifermented tea, black tea and black tea sub-product (BTSP) were used for this study.Water extract contents were significantly higher in black tea and green tea (40.3% and 40.7% w/w, respectively), while semifermented tea and BTSP showed higher levels of crude fibre (22.3% and 20.4% w/w, respectively). Caffeine contents of black teas (2.7% w/w) were significantly higher than in the other types of tea. Green teas revealed the highest concentrations of phenolic compounds and the major antioxidant activities (14.9 g GAE/100g dm and 30.0 g AAE/100g dm, respectively). The results also highlighted significant differences (p<0.05) in colour values between the different types of tea.

Escherichia coli O157 detection limits in artificially contaminated beef and cattle faeces samples were determined using Dynabeads anti E. coli O157 immunomagnetic beads, VIDAS-UP, VIDAS-ICE, and real-time PCR (GeneDisc and LightCycler) systems. Dynabeads anti-E. coli O157 immunomagnetic separation (IMS) and the GeneDisc cycler were the most sensitive methods, and could detect an initial 1 CFU in 25g beef samples after 6h of incubation in modified tryptone soya broth with novobiocin (mTSB+n) or buffered peptone water (BPW). The VIDAS-UP method could detect an initial 10 CFU, while VIDAS-ICE and the LightCycler methods could only detect an initial 100 CFU. Higher detection rates were achieved with 18 hour incubations, where an initial 1 CFU in a 25g sample could be detected with all five methods. For cattle faeces enrichments, Dynabeads anti-E. coli O157 IMS could detect an initial 1 CFU after a 6 h incubation in mTSB+n, while the VIDAS-UP and VIDAS-ICE methods could detect an initial 10 CFU and both PCR methods could only detect an initial 100 CFU. Detection rates were lower in BPW, compared to mTSB+n, with thresholds of 100 CFU for VIDAS-ICE, VIDAS-UP and GeneDisc methods, and >100 CFU for the LightCycler method.