Food safety and nanotechnology: Results from LENA Project Richard Winterhalter
Outline Project LENA Nanoparticles in food and food supplements Colloidal silver Field-Flow-Fractionation Measurement of nanosilver in food supplements ( colloidal silver ) Summary Richard Winterhalter 8 February 212 2
Introduction Application of nanotechnology and nanoparticles also in food production Possible exposition of consumers to nanoparticles? New challenge for food safety authorities Measurement methods for nanoparticles in food must be developed Richard Winterhalter 8 February 212 3
Project LENA (Food safety and nanotechnology) 1. Migration of nanoparticles from food packages into food Fraunhofer Institute for Process Engineering and Packaging (IVV), Product Safety and Analytics, Freising. Roland Franz, Gerd Wolz, Diana Kemmer 2. Analytics and characterisation of nanoparticles in food and food supplements Bavarian Health and Food Safety Authority,Institute for Occupational and Products Safety; Environment related Health Protection (AP), Munich Goals Development of analytical methods for measurement of nanoparticles in food and food supplements (SiO 2, TiO 2, Ag) Appropriate sample preparation (homogenisation methods) What happens to nanoparticles during digestion? Agglomeration/Deagglomeration Richard Winterhalter 8 February 212 4
Nanoparticles in Food and Food Supplements Natural Nanoparticles Micelles Liposomes Proteins Polysaccharides Example: Milk Casein-micelle (2 3 nm) Fat micelles ( 1 2 µm) Richard Winterhalter 8 February 212 5
Nanoparticles in Food and Food Supplements Synthetic (engineered) Nanoparticles Food additives SiO 2 (E 551), TiO 2 (E 171) Organic nanoparticles (micelles, liposomes) Food supplements advertised with nano Colloidal silver as natural antibiotic Richard Winterhalter 8 February 212 6
Nanoparticles in Food and Food Supplements Migration from food contact materials nano-clay, nano-cellulose, TiN (approved explicitly as nano-tin), SiO 2, TiO 2, MgO, ZnO, Ag used in polymers as gas barrier, for improved thermal and mechanical stability, for UV-protection, as antimicrobial agent faster processing of PET bottles (TiN) Richard Winterhalter 8 February 212 7
Nanoparticles in Food and Food Supplements Metallic micro- and nanoparticles metallic debris from milling environmental contamination during crop cultivation 44% of the samples (n=135) contained micro-and nanoparticles ESEM image (A) of debris in a sample of bread with its EDS spectrum ESEM picture of home-made bread (A) with silver micro and nanodebris (B) Source: Investigation of the Presence of Inorganic Micro- and Nanosized Contaminants in Bread and Biscuits by Environmental Scanning Electron Microscopy. A.M. Gatti, D. Tossini, A. Gambarelli, S. Montanari, and F. Capitani, Critical Reviews in Food Science and Nutrition, 49:275 282 (29) Richard Winterhalter 8 February 212 8
Nanosilver in Food and Food Supplements Approved food colour for sweets (silver coating) E 174 silver shining effect, cannot be nano-ag brown colour Migration from nano-ag containing food contact materials Colloidal silver ( food supplement ) Richard Winterhalter 8 February 212 9
Colloidal Silver (nanosilver, mesosilver) Health benefits of Colloidal Silver nano silver as a dietary supplement: -Natural antibacterial, antiviral, antifungal, & antimicrobial effects -Strengthening of the body's immune system -elimination of bad bacteria without harm to good bacteria -While most antibiotics are effective against about half-dozen disease causing organisms, silver is effective against over 65 organisms Richard Winterhalter 8 February 212 1
Asymmetric-Flow-Field-Flow-Fractionation (AF4) Solvent-degasser Channel Slot-Pump HPLC-Pump Sample collector MALS detector HPLC-Pump UV-detector Cross-flow pump Autosampler Richard Winterhalter 8 February 212 11
Theory of AF 4 Laminar flow profile (channel flow) Flow field Diffusion 35 µm Membrane Frit Cross flow t t r r 2 : Retention Time d : Particle Diameter w : Channel thickness V& x : Cross Flow V& : Channel Flow Ch d w V& V& x Ch Richard Winterhalter 8 February 212 12
Steps of separation Eluents/solvents: pure water aqueous solutions (buffers, detergents) organic solvents (e.g. Ethanol, Methanol) Source: Postnova Analytics Richard Winterhalter 8 February 212 13
Detection of particles UV-Detector (28 nm): concentration MALS-Detector (52 nm): particle diameter Multi Angle Light Scattering: measurement of scattered light at various angles: 35, 5, 75, 9, 15, 13, 145 Diode Laser (52 nm) incident light Source: Postnova Analytics scattered light Detector P angular dependent scattering function of spherical nanoparticles 1.8.6.4.2 Debye-Plot P(2) P(5) P(1) P(2).2.4.6.8 1 sin²(ϑ/2) forward scattering 2 nm 2 nm 5 nm 1 nm backward scattering Richard Winterhalter 8 February 212 14
Polystyrene particles (radius 9,5 nm, 29 nm and 5 nm) Detector Signals [V] 1 9 8 7 6 5 4 3 2 1 5 1 BIC 35 BIC 9 BIC 145 Fractogram 15 2 25 3 35 4 45 5 55 Time [min] 6 Differential,5,45,4,35,3,25,2 Size distribution Radius 1,,9,8,7,6,5,4 Cumulative 35,15,1,5,3,2,1 3 1 2 3 Radius [nm] 4 5 Retentionszeit (min) 25 2 15 y =,4627x + 7,184 R 2 =,9998 1 y =,4348x + 6,842 5 R 2 =,9994 1 2 3 4 5 6 Radius (nm) Linear relationship particle radius and retention time blue: radius from MALS detector red: according to manufacturer Richard Winterhalter 8 February 212 15
Reproducibility of AF 4 method Ag-NP in consumer product (spray) solvent 15% MeOH 8 BIC 35 BIC 9 BIC 145 Nano-Ag_2511_ Nano-Ag_2511_1 Nano-Ag_2511_2 Injection time (min) 5 5 4 Cross flow (ml/min) 2. 2. 2. Mean radius (nm) 59.4 63.7 66.8 Detector Signals [V] 7 6 5 4 3 2 1 1 2 3 Time [min] 4 5 6 Nano-Ag_2511_3 4 2.5 66. Nano-Ag_2511_4 Nano-Ag_2511_5 Nano-Ag_2511_6 5 6 7 2. 2. 2. 63.5 64.5 71.2,5,45,4,35 Radius Average Standard deviation 65. 3.6 Differential,3,25,2,15,1,5 2 4 6 Radius [nm] 8 1 Richard Winterhalter 8 February 212 16
Nanoparticles in SiO 2 -containing food supplements Conventional supplements and nano -supplements measured with AF4 after ultrasonic homogenisation 1 2 3 4 5 6 7 8 9 1 no. 1 2 3 4 5 Product Levasil 3 hydrophilic silica sol Aerosil 3 hydrophilic fumed silica Mineral powder Silica powder Silica powder with Calcium Solvent,9% NaCl,2% NovaChem,2% NovaChem,2% NovaChem,2% NovaChem Max. of size distribution (Diameter in nm) 2 2 7 8 22 Range of size distribution (Diameter in nm) 1 7 8 4 1 33 54 58 15 55 6 Silica powder with vitamins,2% NovaChem 1 7 59 7 Nano -Silica powder,2% NovaChem 86 66 22 8 Nano -Silica powder,2% NovaChem 13 7 57 9 1 Nano -Silica powder Nano -Silica sol 5 mm Na 4 P 2 O 7 5 mm Na 4 P 2 O 7 1 12 6 3 6 3 Richard Winterhalter 8 February 212 17
OECD nanosilver standard NM-3 1 5 1 3 5 1 2 1 µg/ml (ppm) UV-signal at different concentrations in water UV-detector (A.U.),14,12,1,8,6,4 2 ppm 1 ppm 5 ppm 3 ppm 1 ppm H2O,2 5 1 15 2 25 3 Retention time (min) Richard Winterhalter 8 February 212 18
OECD nanosilver standard NM-3,35,3,25 UV 4. ml/min 1. ml/min 2.5 ml/min 2. ml/min 1.5 ml/min Method development: different cross flow rates UV-signal,2,15,1,5 1 2 3 4 5 6 Retention time (min) 14 MALS-Signal 9 12 1 8 6 4. ml/min 1. ml/min 2.5 ml/min 2. ml/min 1.5 ml/min MALS 9 4 2 1 2 3 4 5 6 Retention time (min) Richard Winterhalter 8 February 212 19
OECD nanosilver standard NM-3 Particle radius (nm) 5 45 4 35 3 25 2 15 1 5 Radius UV-signal 8 1 12 14 16 18 2 Retention time (min),35,3,25,2,15,1,5 UV-signal Fractogram Size distribution,14,12,1,8 Particles radius (AF 4 ): 8.5 nm Reference value (TEM): 7.5 nm,6,4,2 2 4 6 8 1 12 14 16 18 2 22 24 26 28 3 Particle radius (nm) Richard Winterhalter 8 February 212 2
Colloidal silver samples 1 2 3 4 5 1 ppm 25 ppm 5 ppm 1 ppm 5 ppm Particle radius (nm) Sample No. 2 5,25 45 Radius 4 UV-signal Fractogram,2 35 3,15 25 2,1 15 1,5 5 14 16 18 2 22 24 26 Retention time (min) UV-signal,7,6,5 Size distribution,4,3 Solvent/Eluent: water,2,1 5 1 15 2 25 3 35 Particle radius (nm) Richard Winterhalter 8 February 212 21
Colloidal silver samples particle diameter (nm) measured concentration (ppm) concentration according to manufacturer (ppm) No. 1 13 2 1 No. 2 2 1 25 No. 3 3 11 5 No. 4 24 5 ppm 6 1 No. 5 loss of NP to membrane 5 1 2 3 4 5 Richard Winterhalter 8 February 212 22
Summary Several sources of nanoparticles in food and food supplements Project LENA: 1. NP-migration from food packages and 2. Measurement of NP in food and food supplements Analytical method AF 4 applicable for NP-characterisation Method development necessary: cross flow rates, solvents (buffers, detergent etc.), sample preparation First results from measurement of Ag-NP in colloidal silver Richard Winterhalter 8 February 212 23
Acknowledgement The project LENA (Lebensmittelsicherheit und Nanotechnologie) was funded by the Bavarian State Ministry for Environment and Health Richard Winterhalter 8 February 212 24