nanobiomedicine strategies in food safety
TRANSCRIPT
Nanobiosensors as a Nanobiomedicine Strategies in
Food Safety & Quality Assurance
Dr.A Rafati
Ph.D of Nanobiotechnology
Introduction
• Food Adulteration and spoilage refers to the process by which the quality or the nature of a given food isreduced through addition of adulterants or removal of vital substance.
• through changes in sensory characteristics, food spoilage can be defined as a metabolic process which causesfood products to be unacceptable for human consumption.
• Within every industry, there are set guidelines which dictate how the product is manufactured and stored toensure safety all around. Meat is one of many food types that will perish rapidly if not refrigerated or kept inoptimal conditions
• Food adulterants refer to the foreign and usually inferior chemical substance present in food that cause harmor is unwanted in the food.
• Basically, during food adulteration, small quantity of non-nutritious substances are added intentionally toimprove the appearance, texture or storage properties of the food.
• Food adulteration is quite common in the developing countries.
Food is Adulterated If:
• The food sold does not meet the nature of the substance or quality as per the demandof consumer.
• The food contains inferior or cheaper substance
• The food has been prepared, packed or kept under unclean conditions leading tocontamination.
• Food contains substances that depreciates or injuriously affects the health.
• If the food’s original nature is substituted wholly or partially by abstracting a portion ofvital substance from food.
• If it is an imitation of some other food substance.
Causes of Food Adulteration:
• Profit motive of traders: Done as a part of the business strategy
• Food insecurity: To increase quantity of food production and sales.
• Increased Urbanization: To make maximum profit from food items by fewer investments.
• High population demands: Increased food demand of the population and its changingtrends.
• Illiteracy of general public: Lack of consciousness of proper food consumption.
• Lack of effective food laws
• Lack of government in initiative
Types of Food Adulteration:
• Intentional adulteration: The adulterants are added as a deliberate act with intention
to increase profit. E.G. sand, marble chips, stones, chalk powder, etc.
• Incidental Adulteration: Adulterants are found in food due to negligence, ignorance
or lack of proper facilities. E.G. Packaging hazards like larvae of insects, droppings,
pesticide residues, etc.
• Metallic adulteration: When the metallic substances are added intentionally or
accidentally. Eg: arsenic, pesticides, lead from water, mercury from effluents, tins
from cans, etc.
Methods of Food Adulteration:
• Mixing: Mixing of clay, stones, pebbles, sand, marble chips, etc.
• Substitution: Cheaper and inferior substances being replaced wholly or partially with good ones.
• Concealing quality: Trying to hide the food standard. E.G. adding captions of qualitative food tolow quality for selling.
• Decomposed food: Mainly in fruits and vegetables. The decomposed ones are mixed with goodones
• Misbranding/ False labels: Includes duplicate food stuffs, changing of manufacture and expirydates.
• Addition of toxicants: adding non-edible substances like argemone in mustard oil, low qualitypreservatives, colouring agents, etc.
Health Hazards of Food Adulteration:
Some health hazards associated with specific food adulteration incudes;Mineral oil if added to edible oil and fats can cause cancers.Lead chromate when added to turmeric powder and spices can cause anaemia, paralysis, brain damage and
abortions.Lead added to water, natural and processed food can lead to lead poisoning, foot drop, insomnia,constipation, anaemia, and mental retardation.
Cobalt added to water and liquors and can cause cardiac damage also copper, tin, and zinc can cause colic,vomiting and diarrhoea.Mercury in mercury fungicide treated grains, or mercury-contaminated fish can cause brain damage, paralysis,and death.
Non-permitted colour or permitted food colour like metal yellow, beyond the safe limit in coloured food cancause allergies, hyperactivity, liver damage, infertility, anaemia, cancer and birth defects.
• Food security and safety are recognized as one of the most critical human
priorities since the world's population is continuously growing.
• The industrialization of food and agriculture is a strategy that guarantees
continued access to food.
• However, microbial, chemical, and physical contaminants from harvesting
to storage and marketing of products affect the food quality and safety.
• On the other hand, profiteers have always posed a serious threat to the
public health since they are looking for different tactics to reduce
production costs and achieve higher profits by adulteration.
Major advantages and limitations of traditional
methods for foodborne pathogen detection
Nanotechnology has presented innovative solutions
to meet the challenges of many industries, including
the food and pharmaceutical industry.
Nanosensors are highly advanced yet precise and
sensitive systems capable of detecting one or more
specific physical or chemical phenomena based on a
particular signal.
These sensors operate on a nanometer scale and
even react to the presence of several atoms in a
single gas, which offer significant enhancements in
speed, selectivity, and sensitivity in comparison with
conventional chemical and biological techniques.
Nanosensors
Nanoparticles:
1. Metal NPs: Pure metals (e.g., Au, Ag, Pt, Ti,Zn, Fe, and Tl) or their compounds (e.g., oxides, hydroxides)
Optical properties due to the LSPR and PSPR
2. Magnetic NPs: Magnetic material, often Fe, Ni, and Co
Easy separation with an external magnetic field /Empowering samples for detection through bioconjugation
IO NPs, especially superparamagnetic Fe3O4 (magnetite) NPs, have been the most commonly used in food due
to their lack of toxicity, excellent compatibility, and lack of preservation of residual magnetism after removal of
theexternal magnetic field.
3. Quantum dots: Semiconductors, metals
Fluorescent behavior
The emission of QDs is usually in the range of 450-850 nm.
Summary of sensory properties of some nanomaterials used in
the construction of nanosensors
Schematic diagrams (top) and transmission
electron microscopy figures (bottom) of various
nanoparticles. (a) Spherical (b) nanorods (c)
multibranched (d) shell-core (e) quantum dots; (f)
grapheme; (g) carbon nanotubes; (h) nanoarray
Application of AuNPs in the various types of biosensors
Dynamic light scattering-based detection of aflatoxin M1 using gold nanoparticle-based probes.
In aflatoxin M1-contaminated samples, the aflatoxin M1 displaced nanoprobes by competitive binding to antibodies.
The concentration of free nanoprobes was measured using dynamic light scattering reading that was proportional to quantity of
aflatoxin M1 in test samples.
Schematic representation for the mechanism of melamine detection in milk products
using gold/Au nanoparticles and visual color changes from red to blue in the presence
of 1 ppm melamine
(a) Synthesis of MnFe2O4@Au core/shell NPSand
(b) (b) SERS method of Staphylococcus aureus detection
AuNPs were decorated on the surface of
magnetic NPs (MNPs) to enable both detection
and separation of bacteria.
MnFe2O4 NP cores were coated with a
polyethylene imine layer (+charge) followed by
AuNPs shell (ve charge) seeding on the surface
through electrostatic interactions.
The Au MNPs were bound to Staphylococcus
aureus and the platform was used for separation
and detection of the target bacteria.
The method was able to detect 10 cells per mL.
In a study to detect milk adulteration, a paper-based
scalable pH sensor derived from electrospun
halochromic nanofibers was synthesized.
Color variations in the pH range of 110:
(A) reference dye solution and
(B) electrospun nylon 6 nanofibers with universal indicator
In a study to detect milk adulteration, a paper-based scalable pH sensor derived from electrospun halochromic
nanofibers was synthesized.
The sensor manifested into three unique color-signatures corresponding to pure (6.6#pH#6.9), acidic (pH,6.6), and
basic (pH.6.9) milk samples, enabling a colorimetric detection mechanism.
The thicknesses of pure nylon nanofibers and the composite nanofibers were observed to be in the range 100-200
nm. The sensor strip was dipped in a milk sample and then imaged with a smartphone.
The Velcro-like food sensor, made
from an array of silk micro needles,
can pierce through plastic packaging
to sample food for signs of spoilage
and bacterial contamination.
The researchers attached the sensor
to a fillet of raw fish that they had
injected with a solution contaminated
with E. coli. After less than a day, they
found that the part of the sensor that
was printed with bacteria-sensing
bioink turned from blue to red — a
clear sign that the fish was
contaminated. After a few more
hours, the pH-sensitive bioink also
changed color, signaling that the fish
had also spoiled.
Schematic illustration of
monomolecular methods for detection
of pork myoglobin in this study. Pork-
adulterated meat samples were selected
and extracted with ultrasound bath. the
aptamer-conjugated MNP detects
myoglobin, then the extra material is
removed from the magnetic plate by
washing, and finally, based on the
colorimetric technique in the complex,
the presence of pork myoglobin in the
meat sample is detected.
the capabilities of g-quadruplex aptamer coupled to magnetic nanoparticles (MNPs) as hybrid
nanomaterials for quantified measurement AFB1 by colorimetric assay for via a smartphone detector
Mitigation Measures for Addressing Food
Adulteration:
• There must be proper surveillance of the implementation food laws.
• There should be monitoring of the activities with periodical records of hazards regarding foodadulteration.
• There should be periodical training programs for Senior Officer/Inspector/Analysts for foodsafety
• There should be consumer awareness programs organized by holdingexhibitions/seminars/training programs and publishing pamphlets.
• There should be strict actions regarding the punishment for those who are involved in foodadulteration.
• There should be help and support from International INGOs for implementation of food laws.
