Analytical methods in assurance of food quality, safety and origin

1
Analytical methods in assurance of food quality,
safety and origin

• Romuald I. Zalewski
• Poznan University of Economics, Poznan, Poland

2
Introduction

• EU is establishing a variety of measures to
  protect quality, safety, authenticity and the
  rights of all parties in the food chain, between
  a farm and a consumer table
• Regulation 178/2002 introduced several procedures
  in matters of food safety. For example a European
  Food Safety Authority (EFSA) shall
• provide scientific advice and technical support,
  independent information on all matters (see 1
  art. 22, 23)
• establish monitoring procedures for searching
  for, collating and analyzing information and data
  with a view to the identification of risk (1
  Art. 34) and rapid alert system (1 Art 35).

3
Variety of the food related risks

• Pathogenic microorganism, their metabolites,
  viruses, parasites, toxins etc.,
• Natural toxic substances normally present in
  foodstuffs or raw materials, various chemicals
  (pesticides, herbicides, antibiotics, detergents,
  heavy metals) which remain from the various
  earlier treatments or were added by chance or on
  purpose (terrorism),
• Particles of metals, glass, plastics, dust and
  other unwanted physical matter.

4
Food born diseases

• In past distributed localy
• New days distributed globaly
• through global operation of producers and
• frequently as a news due to radio, TV, Internet
• ignoring the warning signs from market
• non effective public relations

5
The best defence

• Good risk assessment analysis (within HACCP
  implementation),
• Immediate response to signals,
• honest explanation of issue,
• undertaken measures to localize treats,
• advertising if a product recall is necessary,
• good co-operation with important clients,
• reassurance that the incident is being handled in
  a controlled manner.

6
Risk assessment
shall be based on the available scientific
evidence and undertaken in an independent,
objective and transparent manner
7
Indicators of food quality and authenticity (1/2)

• The EU has very strict rules of origin referring
  to degree of transformation to be fulfilled by
  product declared as originated in the country
  X.
• The system consists of
• PDO protected designation of origin,
• PGI-protected geographical indication and
• TSG traditional specialty guaranteed.

8
Indicators of food quality and authenticity (2/2)

• The quality characteristics (physical, chemical,
  sensory) of the products protected by above
  mentioned designations are guaranteed by
  respective Regulatory Councils.
• The sale of products covered by quality
  protection system steadily increase.
• The voluntary labeling is necessary for signaling
  high quality of products versus various generic
  products of lover quality (substitute products).

9
New times new methods

• New methods are frequently time saving, but are
  more expensive when used.
• Their application require a well-trained staff,
  availability of reference materials, proficiency
  testing, establishing a net of reference
  laboratories in each country and other features.
  Quality assurance systems implemented in a form
  of HACCP and in addition tracking and tracing
  system will call for easy and clear analytical
  methods for examination of parameters at CCP
  (critical control points). Also the other
  procedures for a risk assessment (Regulation
  178/2002) must relay on proven scientific and
  analytical methods.

10
Antibiotics in food important field

• Antibiotics are often used as feed additives to
  increase weight gain, to improve the efficiency
  of the feed conversion and mainly as prophylactic
  treatment to avoid sickness.
• The EU Directive 70/524/EEC or Council Regulation
  EEC 2377/90 regulates the use of antibiotics.
  Their residues present a potential hazard for a
  human health. Most commonly used test to
  determine antibacterial substances is a
  traditional microbiological test, but the need
  for more efficient method is obvious.

11
New four-step strategy

• Identification of broad category (e. g.
  sulphonamides, beta-lactams, tetracydines, amino
  glycosides, macrolides, phenicoles etc.)
• Detailed chemical identification using GC, GC/MS,
  HPLC/UV, LC/MS or other.
• The instrumental method must be tested and
  validated in relation to maximum residue limit
  (MRL), allowed by EU standards.

12
Testing of food, water, and equipment for the
presence of pathogenic organisms (1/2)

• Current methods are painstaking and lengthy. The
  development of portable easy-to-use kits basing
  on biosensors will bring large improvements. Two
  microorganisms are of high interest for detection
  with biosensors Criptosporidium parvum and
  Escherichia coli. The method relay on separation
  of messenger RNA using heat shock, extraction and
  purification. Finally isothermal (410 C) Nucleic
  acid Sequence-Based Amplification is applied, as
  a very convenient technique for field-use and
  portable detection.

13
Testing for the presence of pathogenic organisms
(2/2)

• RNA is than quantified with membrane based
  DNA/RNA biosensor, using liposome signal
  amplification. Liposomes are nano-vesicles with
  an inner cavity surrounded by a phospho-lipid
  bilayer. Inside this cavity marker molecule (dye)
  is entrapped, which change the color when
  interact with photogenic alive organism.
• Another way of fast analysis for microorganisms
  relay on ATP fluorescence. The special easy kit
  has been introduced.

14
Heavy metals in soil and plastics

• atomic absorption spectrometry,
• laser-induced breakdown spectrometry (LIBS)
• The analyte is heated locally by the pulsed laser
  beam and evaporated to excited plasma which emit
  radiation. The radiation is observed with
  Czarny-Tuner or Pascher-Runge spectrometer
  Typical limits of detection of several heavy
  metals in soil with this technique are in the
  range 10-100ppm.
• coupling LIBS with laser-included fluorescence
  allows decreasing this limit to 1 ppm. The
  flexible measuring probe, consuming less energy
  and using fiber optics are now under development.
  

15
Determination of ions in water (for purity check)

• Till now various techniques are used and approved
  as official methods by ASTM, EPA and ISO. One can
  mention
• ion selective electrodes, titrations,
  spectrofotometry and electrochemistry,
• ion chromatography is well established
  (Whitehead, 2001) F-, Cl-, Br-, NO2-, NO3-,
  SO42- - 5 ppt
• NH4, Ca2, Li, Mg2, Na, K - 1 ppt
• Co2, Co2, Fe3, Mn2, Ni2, Zn2 - 2 ppt
• CH3COO-, HCOO-, (COO)2-, - 50 ppt

16
Residues of pesticedes difficult task (1/2)

• For screening purpose - multi residue methods
  (MRMs), because single analyte methods are not
  practical. MRMs allow inspecting a few dozen of
  compounds,
• methods applying GC/MS increase this number to
  200-300 compounds. Perhaps the best and most
  comprehensive method allowing detection of 567
  different pesticide, metabolites and endocrine
  disrupters, has been described (Wylie, Meng,
  2001).

17
Residues of pesticedes difficult task (2/2)

• method with two GC instruments equipped with Mass
  Selective Detector and Atomic Emission Detector,
  and a ChemStation software for instrument
  control, data collection and analysis. The
  Pesticide Database has been prepared and used.
  The run took 42 minutes and allow identification
  of compounds with detection limit bellow 500
  pg/ml (or at the ppt range).

18
Near infrared reflectance spectrometry (NIRS)

• Application of NIRS (800 2500 nm) in food
  analysis is growing recently dramatically due to
  a progress in computing facilities.
• Various overtones and combination bands of
  fundamental IR bands (CH, OH, NH) can be found
  and provide capability for the identification and
  quantification of various food constituents such
  as moisture, protein, fats and oils,
  carbohydrates, pigments and other additives.
• NIR analyzer measures absorption, transmission or
  reflection of the light as a function of
  wavelength. Results are produced and analyzed in
  2-3 minutes.

19
Near infrared reflectance spectrometry (NIRS)

• Liquid or solid samples are used without special
  complicated treatment.
• Solids and grain could be grinded.
• Various viscous liquids, emulsions, creams, pasta
  could be measured in instrument compartment on
  even at distance with a special fiberglass
  adapter.
• The recorded spectra are not well developed (as
  compared to multi peak IR) and advanced
  chemometric software is necessary for analysis of
  spectra. In many cases derivatives of spectra are
  applied.

20
Natural yoghurts
21
Preliminary clustering in tri-dimensional space
of PC
Farma Koscian
Danone Danonesugar Bakoma
22
Mayonnaise
23
NIRS spetctra of fats
24
Fats distribution in a space of PCAs
25
PLS1, PLS2, SIMCA
x1 x1 ... xn y1 ... yn
s1 s1
. .
. X . Y
. (NIRS) .
. .
sn sn
PLS1
PLS2

26
Correlation of unsaturated fatty acids measured
by reference method and predicted by NIRS