Do Food Nanomaterials Pose a Safety Concern

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Do Food Nanomaterials Pose a Safety Concern?
Issues for Safety Evaluation/Risk
Assessment Presentation by Nga Tran Food
Products Associations Workshop on
Nanomaterials September 18, 2006 Washington, DC

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Nanoscience and Nanotechnologies

• Nanoscience
• The study of phenomena and manipulation of
  materials at atomic, molecular and macromolecular
  scales, where properties differ significantly
  from those at a larger scale
• Nanotechnologies
• The design, characterization, production and
  application of structures, devices and systems by
  controlling shape and size at nanometer scale.

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More definitions

• Nanoscale having one or more dimensions of the
  order of 100 nm or less
• Nanomaterial material with one or more external
  dimensions, or an internal structure, which could
  exhibit novel characteristics compared to the
  same material without nanoscale features.
• Nanoparticle particle with one or more
  dimensions at the nanoscale.
• Nanocomposite composite in which at least one of
  the phases has at least one dimension on the
  nanoscale.
• Nanostructured having a structure at the
  nanoscale
• (EU, SCENIHR/002/05)

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Nanotechnology in our Lives

• Over 200 manufacturer-identified nano consumer
  products are commercially available worldwide

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• NANOTECHNOLOGY AND FOODS
• What are we dealing with?
• Marketing and advertisement confusion and hype
• To understand the potential safety issues, we
  need to define what types of nano applications
  are of interest
• Whats REALLY likely to be commercialized
  earliest in the mainstream food industry???

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Agricultural Application

• Nano-formulation of pesticides
• increase water solubility, enhance application,
  increase stability, optimize efficacy
• microemulsion concentrate (enhance solubility)
• encapsulation (release controls)

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A Query of Nanotechnology Food Products --
Courtesy of the Woodrow Wilson Center
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NanoClusters a nanosize powder that combines
with nutritional supplements. When consumed, it
reduces the surface tension of foods and
supplements to increase wetness and absorption of
nutrients. 1-5 nanometers in diameter, made
from a silica-mineral hydride complex -- on
exposure to moisture it releases H- ions, and
becomes an antioxidant dietary supplement
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Familiar nanostructures in foods

• Many food proteins are globular structures
  between 10's of nm to 100s nm in size - true
  nanoparticles
• The majority of polysaccharides and lipids are
  linear polymers
• less than 2 nms in thickness
• one dimensional (1D) nanostructures
• Preparing and stabilizing foams and emulsions
• creating 2D layered nanostructures
• one molecule thick, at the air-water or oil-water
  interface
• Setting a gel, or adding polymers to delay the
  sedimentation of dispersions or the creaming of
  emulsions
• creating 3D nanostructures, by causing food
  biopolymers to assemble into fibrous networks
• Boiling starch to make custard -- melting small
  3D crystalline 10s nm in thickness

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Potential future manipulation at the nanoscale

• Designing more complex multilayer structures
  using nanofabrication
• Adding an extra layer to consolidate the
  weaknesses in the protein network -- stabilize
  against surfactant or lipid attack
• Designing the properties of the interfacial
  layers by carefully choosing the molecular
  components
• Enhancing or inhibiting coalescence of droplets
• Regulating the porosity of the interface to
  optimize encapsulation and release
• Designing new surface coatings or barriers

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Alteration of intrinsic properties of foods on
the nano-scale

• Nanoparticles may be used in foods to alter other
  properties. For example, margarine, ice cream,
  butter and mayonnaise all belong to a class of
  foods known as colloids, where small particles
  are dispersed in some other medium liquid, gas
  or solid
• Ongoing research and patent on new ways to make
  colloids using nanoparticles that will extend
  shelf-life, prolong flavor sensation in the
  mouth, alter texture and improve stability

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Nano-delivery system for conventional nutrients

• Certainly nanoparticles may seem attractive as
  delivery vehicles designed to target release
  of nutrients
• One way to preserve an active component is by
  putting it in a protective envelope.
• The envelope can be engineered to dissolve or the
  active ingredient can be made to diffuse through
  the envelope triggered by the right stimulus

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Nano-scale Food additives - 64M questions(1)
are these really novel?(2) is anybody using them?

• BASFs synthetic lycopene is formulated at the
  nanoscale
• more easily absorbed
• increases shelflife (on market)
• Edible products with inorganic coatings
• coatings as barriers to prevent oxygen or
  moisture from reaching the product
• increasing shelf life.
• SiO2 and TiO2 are specifically mentioned
• (microencapsulation, distribution of
  micro-particle sizes likely contained nano-size,
  approved use, Not novel?)
• An antibacterial nanometer powder
• nanometer zirconium phosphate particles as
  carrier of an active antibacterial component
• broad spectrum
• (Patent data collected by ETC Qingtian New
  Material Research Development Co. (China) Food
  Additive CN1409966A 2003-04-16)

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Food contact materials

• Anti-microbial agents directly on the surface of
  the coated film
• Increase or decrease gas permeability as required
  for different products
• Improve the mechanical and heat-resistance
  properties and lower the oxygen transmission rate

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POTENTIAL ISSUES GIVEN ASSUMED TYPES OF NANO-FOOD
PRODUCTS (THERE MAY BE OTHERS) RUDIMENTS OF A
RISK ANALYSIS/PRIORITIZATION FRAMEWORK
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• Manipulation of conventional food process on the
  nanoscale
• Potential issue alteration of food composition
  or nutritional profile
• Available of detailed understanding of the
  nanostructures present in raw materials or
  processed food
• use rational approaches to select new materials,
  or to enhance quality through food processing

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• Enhanced delivery systems
• Potential issue alterations in bioavailability -
  absorption, distribution, metabolism or excretion
  characteristics
• Enhanced delivery of nutrients
• Unintended consequence of getting too much of a
  good thing? The U-shape curve effect?
• Neutraceuticals -- blurring of the distinction
  between functional foods and pharmaceuticals?
• Additives (e.g. dyes/flavors)
• Enhanced absorption from GI?
• Unintended consequences?
• Contaminants -- Increase bioavailability of not
  very bioavailable contaminants in foods?

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• Nanoscale ingredients that are natural at
  macroscale
• In the case of additives that also occur
  naturally in foods, it is not clear what the
  nano-specific safety issues are
• Ultimately, the digestive enzymes bring the
  natural macro particles back down to
  nano-scale.... conventional food is nano-scale by
  the time it reaches the bloodstream

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• Nanoscale additives not naturally occurring in
  the food
• How relevant is the safety data at macro-level?
• How do nanoscaled additive particles behave in
  food matrix? Do they stay agglomerated and
  bounded until digested in the gut?
• What are the relevant chemical and physical
  characteristics of these particles in a food
  matrix?
• What are their characteristics once in the gut?
  Rate of translocation to other target tissue?

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• Food contact materials (e.g.,packaging, surfaces)
• Is nanomaterial bound? Or designed to migrate
  into the food?
• Migration potential/measurement?
• Erosion of surfaces during use?
• Fate in the food matrix?

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LESSONS LEARNED FROM NON-FOODS NANOTECHNOLOGY

• Much of the research focuses on
• Engineered nanomaterials important for
  electronics and pharmaceuticals
• e.g., Novel carbon structures single-walled
  carbon nanotubes (SWNT), buckeyballs
• e.g., Drug delivery systems with specific tissue
  affinities
• Inhalation or dermal exposures, some e-fate and
  ecotox
• Comparison to effects of naturally-occurring
  nanoparticulate air pollutants on lung tissue
• In vitro cytotoxicity assays

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What safety considerations can be gleamed from
nanos in electronics, pharmaceuticals and
cosmetics?

• Some substances show increased/altered toxicity
  in the nanoscale as compared to their effects
  when larger sized
• Sometimes effects seen are different from those
  observed when dosing with the same material at
  micro- or macroscale
• Local inflammation, immune responses
• Different target organs
• Safety considerations in production worker
  risks
• Safety considerations in product use
  interaction with biological structures (human,
  animal and ecological targets)

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How relevant is current safety assessment
framework that is born out of particles and
fibers to nanofoods?

• Particle properties
• Measurement and Exposure Assessment
• Toxicology

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What is different about engineered
nanomaterials?The significance of structure
The many shapes of ZnO - Courtney of Prof. Z.L.
Wang, Georgia Tech
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An experiment in the significance of structure on
health impact
Nano-Materials Devices
Macro-Materials
Liquids
Gases Vapors
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Risk Characterization Context
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Data on ingestion exposures

• Very scarce
• Jani at el 1990 34 (50nm) and 26 (100 nm)
  polystyrene particles were absorbed,
  respectively.
• 300 nm were absent from the blood
• No particles were detected in heart or lung
  tissue.
• Hillery et al, 1994 10 of 60nm polystyrene
  particles recovered from GI tissuesmost in
  lymphoid tissues (Peyers patches and lymphoid
  aggregates in the large intestines)
• Szenkuti (1997) the smaller latex particle
  diameter the faster they could permeate the mucus
  to reach the colonic enterocytes
• 14 nm diameter permeated within 2 min, 415 nm (30
  min)
• 1000 nm particles unable to cross barrier

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Algorithm of toxicodynamics on nanoparticles
(based on inhaled particles) (SCENIHR/002/05)
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Safety Decision Analysis framework
Overview of influence diagram for assessing the
safety of nanoparticles (Morgan, 2005)
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Morgans (2005) Expert Elicitation

• Aerosol physicist
• Bioengineering and medicine
• Biomaterials engineering
• Chemistry/toxicology of ultrafines
• Chemistry of nanomaterials
• Exposure assessment and risk management
• Mechanical engineer
• Risk assessment
• Toxicology

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Particle-related characteristics module (Morgan,
2005)
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Hypothetical Uptake Capacity Module(Morgan 2005)
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Hypothetical and Simplified Safety Influence
Diagram for Nanomaterials in Foods
Exposure
Presence of nano-materials
Types of nano-foods
Human Health Risks
GI Uptake capacity
Transport/Fate
Food relevant nano particle-related
characteristics
Toxic Effects
Toxicity
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CONCLUSIONS

• Potential
• Generally revolutionary technology, with many
  societal and environmental benefits anticipated
• In foods, it will greatly depends on what
  technology we are talking about
• Risk
• There may be unanticipated roadblocks, including
  unexpected risk to human health and the
  environment, and
• Lack of public acceptance

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• Need for interaction between multiple disciplines
• Food technologist/scientist
• Engineers
• Chemists
• Toxicologists
• Nutritionists
• Exposure assessor
• Risk assessor
• Strawmen/case studies to develop the risk
  framework

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Getting it right first time!

• Societal Acceptance
• Minimizing risk
• Maximizing benefits