analytical methods in assurance of food quality, safety and origin romuald i. zalewski poznań...

Analytical methods in assurance of food quality, safety and origin

Romuald I. Zalewski

Poznań University of Economics, Poznań, Poland

R.I. Zalewski, Poznań University of Economics

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.


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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-, SO4

2- - 5 ppt

– NH4+, Ca2+, Li+, Mg2+, Na+, K+ - 1 ppt

– Co2+, Co2+, Fe3+, Mn2+, Ni2+, Zn2+ - 2 ppt

– CH3COO-, HCOO-, (COO)2-, - 50 ppt


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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).


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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/l (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

Danone

Danone+sugar

Bakoma

Farma Kościan


22

Mayonnaise


23

NIRS spetctra of fats

log1/R

23482308~1934

1762

1727~1450

1214

1165930


24

Fats distribution in a space of PCA’s

Livia

Tina

Delma

Finea

Łaciate

Masło stołoweNadwarciańska

Masło Extra1

Górskie

Masło Extra 2

MasmixRama


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x1 ... xn y1 ... yn

s1 s1

. .

. X . Y

. (NIRS) .

. .

sn sn

PLS1

PLS2

PLS1, PLS2, SIMCA


26

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

analytical methods in assurance of food quality, safety and origin romuald i. zalewski poznań...

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