Macroscopic quantum phenomena

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Macroscopic_quantum_phenomena 

Macroscopic quantum phenomena are processes showing quantum behavior at the macroscopic scale, rather than at the atomic scale where quantum effects are prevalent. The best-known examples of macroscopic quantum phenomena are superfluidity and superconductivity; other examples include the quantum Hall effect and topological order. Since 2000 there has been extensive experimental work on quantum gases, particularly Bose–Einstein condensates.

Between 1996 and 2016 six Nobel Prizes were given for work related to macroscopic quantum phenomena. Macroscopic quantum phenomena can be observed in superfluid helium and in superconductors, but also in dilute quantum gases, dressed photons such as polaritons and in laser light. Although these media are very different, they are all similar in that they show macroscopic quantum behavior, and in this respect they all can be referred to as quantum fluids.

Quantum phenomena are generally classified as macroscopic when the quantum states are occupied by a large number of particles (of the order of the Avogadro number) or the quantum states involved are macroscopic in size (up to kilometer-sized in superconducting wires).

Consequences of the macroscopic occupation

Fig. 1 Left: only one particle; usually the small box is empty. However, there is a nonzero probability that the particle is in the box. This chance is given by Eq. (3). Middle: a few particles. There are usually some particles in the box. We can define an average, but the actual number of particles in the box has large fluctuations around this average. Right: a very large number of particles. There is generally a large number of particles in the box. The fluctuations around the average are small compared to the number in the box.

The concept of macroscopically-occupied quantum states is introduced by Fritz London. In this section it will be explained what it means if a single state is occupied by a very large number of particles. We start with the wave function of the state written as

${\displaystyle \Psi =\Psi _{0}\exp(i\varphi )}$

(1)

with Ψ₀ the amplitude and ${\displaystyle \varphi }$ the phase. The wave function is normalized so that

${\displaystyle \int \Psi \Psi ^{*}\mathrm {d} V=N_{s}.}$

(2)

The physical interpretation of the quantity

${\displaystyle \Psi \Psi ^{*}\Delta V}$

(3)

depends on the number of particles. Fig. 1 represents a container with a certain number of particles with a small control volume ΔV inside. We check from time to time how many particles are in the control box. We distinguish three cases:

1. There is only one particle. In this case the control volume is empty most of the time. However, there is a certain chance to find the particle in it given by Eq. (3). The probability is proportional to ΔV. The factor ΨΨ^∗ is called the chance density.

2. If the number of particles is a bit larger there are usually some particles inside the box. We can define an average, but the actual number of particles in the box has relatively large fluctuations around this average.

3. In the case of a very large number of particles there will always be a lot of particles in the small box. The number will fluctuate but the fluctuations around the average are relatively small. The average number is proportional to ΔV and ΨΨ^∗ is now interpreted as the particle density.

In quantum mechanics the particle probability flow density J_p (unit: particles per second per m²), also called probability current, can be derived from the Schrödinger equation to be

${\displaystyle {\vec {J}}_{p}={\frac {1}{2m}}\left(\Psi (i{\frac {h}{2\pi }}{\vec {\nabla }}-q{\vec {A}})\Psi ^{*}+\mathrm {cc} \right)}$

(4)

with q the charge of the particle and ${\displaystyle {\vec {A}}}$ the vector potential; cc stands for the complex conjugate of the other term inside the brackets. For neutral particles q = 0, for superconductors q = −2e (with e the elementary charge) the charge of Cooper pairs. With Eq. (1)

${\displaystyle {\vec {J}}_{p}={\frac {\Psi _{0}^{2}}{m}}\left({\frac {h}{2\pi }}{\vec {\nabla }}\varphi -q{\vec {A}}\right).}$

(5)

If the wave function is macroscopically occupied the particle probability flow density becomes a particle flow density. We introduce the fluid velocity v_s via the mass flow density

${\displaystyle m{\vec {J}}_{p}=\rho _{s}{\vec {v}}_{s}.}$

(6)

The density (mass per m³) is

${\displaystyle m\Psi _{0}^{2}=\rho _{s}}$

(7)

so Eq. (5) results in

${\displaystyle {\vec {v}}_{s}={\frac {1}{m}}\left({\frac {h}{2\pi }}{\vec {\nabla }}\varphi -q{\vec {A}}\right).}$

(8)

This important relation connects the velocity, a classical concept, of the condensate with the phase of the wave function, a quantum-mechanical concept.

Superfluidity

Main article: Superfluid

 

Fig. 2 Lower part: vertical cross section of a column of superfluid helium rotating around a vertical axis. Upper part: Top view of the surface showing the pattern of vortex cores. From left to right the rotation speed is increased, resulting in an increasing vortex-line density.

At temperatures below the lambda point, helium shows the unique property of superfluidity. The fraction of the liquid that forms the superfluid component is a macroscopic quantum fluid. The helium atom is a neutral particle, so q = 0. Furthermore, when considering helium-4, the relevant particle mass is m = m₄, so Eq. (8) reduces to

${\displaystyle {\vec {v}}_{s}={\frac {1}{m_{4}}}{\frac {h}{2\pi }}{\vec {\nabla }}\varphi .}$

(9)

For an arbitrary loop in the liquid, this gives

${\displaystyle \oint {\vec {v}}_{s}\cdot {\vec {\mathrm {d} s}}={\frac {h}{2\pi m_{4}}}\oint {\vec {\nabla }}\varphi \cdot {\vec {\mathrm {d} s}}.}$

(10)

Due to the single-valued nature of the wave function

${\displaystyle \oint {\vec {\nabla }}\varphi \cdot {\vec {\mathrm {d} s}}=2\pi n}$

(11a)

with n integer, we have

${\displaystyle \oint {\vec {v}}_{s}\cdot {\vec {\mathrm {d} s}}={\frac {h}{m_{4}}}n.}$

(11b)

The quantity

${\displaystyle \kappa ={\frac {h}{m_{4}}}\approx 1.0\times 10^{-7}\,\mathrm {m^{2}/s} }$

(12)

is the quantum of circulation. For a circular motion with radius r

${\displaystyle \oint {\vec {v}}_{s}\cdot {\vec {\mathrm {d} s}}=2\pi v_{s}r.}$

(13)

In case of a single quantum (n = 1)

${\displaystyle v_{s}={\frac {1}{2\pi r}}\kappa .}$

(14)

When superfluid helium is put in rotation, Eq. (13) will not be satisfied for all loops inside the liquid unless the rotation is organized around vortex lines (as depicted in Fig. 2). These lines have a vacuum core with a diameter of about 1 Å (which is smaller than the average particle distance). The superfluid helium rotates around the core with very high speeds. Just outside the core (r = 1 Å), the velocity is as large as 160 m/s. The cores of the vortex lines and the container rotate as a solid body around the rotation axes with the same angular velocity. The number of vortex lines increases with the angular velocity (as shown in the upper half of the figure). Note that the two right figures both contain six vortex lines, but the lines are organized in different stable patterns.

Superconductivity

Main article: Superconductivity

In the original paper Ginzburg and Landau observed the existence of two types of superconductors depending on the energy of the interface between the normal and superconducting states. The Meissner state breaks down when the applied magnetic field is too large. Superconductors can be divided into two classes according to how this breakdown occurs. In Type I superconductors, superconductivity is abruptly destroyed when the strength of the applied field rises above a critical value H_c. Depending on the geometry of the sample, one may obtain an intermediate state consisting of a baroque pattern of regions of normal material carrying a magnetic field mixed with regions of superconducting material containing no field. In Type II superconductors, raising the applied field past a critical value H_c1 leads to a mixed state (also known as the vortex state) in which an increasing amount of magnetic flux penetrates the material, but there remains no resistance to the flow of electric current as long as the current is not too large. At a second critical field strength H_c2, superconductivity is destroyed. The mixed state is actually caused by vortices in the electronic superfluid, sometimes called fluxons because the flux carried by these vortices is quantized. Most pure elemental superconductors, except niobium and carbon nanotubes, are Type I, while almost all impure and compound superconductors are Type II.

The most important finding from Ginzburg–Landau theory was made by Alexei Abrikosov in 1957. He used Ginzburg–Landau theory to explain experiments on superconducting alloys and thin films. He found that in a type-II superconductor in a high magnetic field, the field penetrates in a triangular lattice of quantized tubes of flux vortices.

Fluxoid quantization

For superconductors the bosons involved are the so-called Cooper pairs which are quasiparticles formed by two electrons. Hence m = 2m_e and q = −2e where m_e and e are the mass of an electron and the elementary charge. It follows from Eq. (8) that

${\displaystyle 2m_{e}{\vec {v}}_{s}={\frac {h}{2\pi }}{\vec {\nabla }}\varphi +2e{\vec {A}}.}$

(15)

Integrating Eq. (15) over a closed loop gives

${\displaystyle 2m_{e}\oint {\vec {v}}_{s}\cdot {\vec {\mathrm {d} s}}=\oint \left({\frac {h}{2\pi }}{\vec {\nabla }}\varphi +2e{\vec {A}}\right)\cdot {\vec {\mathrm {d} s}}}$

(16)

As in the case of helium we define the vortex strength

${\displaystyle \oint {\vec {v}}_{s}\cdot {\vec {\mathrm {d} s}}=\kappa }$

(17)

and use the general relation

${\displaystyle \oint {\vec {A}}\cdot {\vec {\mathrm {d} s}}=\Phi }$

(18)

where Φ is the magnetic flux enclosed by the loop. The so-called fluxoid is defined by

${\displaystyle \Phi _{v}=\Phi -{\frac {2m_{e}}{2e}}\kappa .}$

(19)

In general the values of κ and Φ depend on the choice of the loop. Due to the single-valued nature of the wave function and Eq. (16) the fluxoid is quantized

${\displaystyle \Phi _{v}=n{\frac {h}{2e}}.}$

(20)

The unit of quantization is called the flux quantum

${\displaystyle \Phi _{0}={\frac {h}{2e}}=2.067833758(46)\times 10^{-15}}$ Wb.

(21)

The flux quantum plays a very important role in superconductivity. The earth magnetic field is very small (about 50 μT), but it generates one flux quantum in an area of 6 μm by 6 μm. So, the flux quantum is very small. Yet it was measured to an accuracy of 9 digits as shown in Eq. (21). Nowadays the value given by Eq. (21) is exact by definition.

Fig. 3. Two superconducting rings in an applied magnetic field
a: thick superconducting ring. The integration loop is completely in the region with v_s = 0;
b: thick superconducting ring with a weak link. The integration loop is completely in the region with v_s = 0 except for a small region near the weak link.

In Fig. 3 two situations are depicted of superconducting rings in an external magnetic field. One case is a thick-walled ring and in the other case the ring is also thick-walled, but is interrupted by a weak link. In the latter case we will meet the famous Josephson relations. In both cases we consider a loop inside the material. In general a superconducting circulation current will flow in the material. The total magnetic flux in the loop is the sum of the applied flux Φ_a and the self-induced flux Φ_s induced by the circulation current

${\displaystyle \Phi =\Phi _{a}+\Phi _{s}.}$

(22)

Thick ring

The first case is a thick ring in an external magnetic field (Fig. 3a). The currents in a superconductor only flow in a thin layer at the surface. The thickness of this layer is determined by the so-called London penetration depth. It is of μm size or less. We consider a loop far away from the surface so that v_s = 0 everywhere so κ = 0. In that case the fluxoid is equal to the magnetic flux (Φ_v = Φ). If v_s = 0 Eq. (15) reduces to

${\displaystyle 0={\frac {h}{2\pi }}{\vec {\nabla }}{\varphi }+2e{\vec {A}}.}$

(23)

Taking the rotation gives

${\displaystyle 0={\frac {h}{2\pi }}{\vec {\nabla }}\times {\vec {\nabla }}\varphi +2e{\vec {\nabla }}\times {\vec {A}}.}$

(24)

Using the well-known relations ${\displaystyle {\vec {\nabla }}\times {\vec {\nabla }}\varphi =0}$ and ${\displaystyle {\vec {\nabla }}\times {\vec {A}}={\vec {B}}}$ shows that the magnetic field in the bulk of the superconductor is zero as well. So, for thick rings, the total magnetic flux in the loop is quantized according to

${\displaystyle \Phi =n\Phi _{0}.}$

(25)

Interrupted ring, weak links

Fig. 4. Schematic of a weak link carrying a superconducting current i_s. The voltage difference over the link is V. The phases of the superconducting wave functions at the left and right side are assumed to be constant (in space, not in time) with values of φ₁ and φ₂ respectively.

Weak links play a very important role in modern superconductivity. In most cases weak links are oxide barriers between two superconducting thin films, but it can also be a crystal boundary (in the case of high-Tc superconductors). A schematic representation is given in Fig. 4. Now consider the ring which is thick everywhere except for a small section where the ring is closed via a weak link (Fig. 3b). The velocity is zero except near the weak link. In these regions the velocity contribution to the total phase change in the loop is given by (with Eq. (15))

${\displaystyle \Delta \varphi ^{*}=-{\frac {2\pi }{h}}2m_{e}\int _{\delta }{\vec {v}}_{s}\cdot {\vec {\mathrm {d} s}}.}$

(26)

The line integral is over the contact from one side to the other in such a way that the end points of the line are well inside the bulk of the superconductor where v_s = 0. So the value of the line integral is well-defined (e.g. independent of the choice of the end points). With Eqs. (19), (22), and (26)

${\displaystyle \Phi _{a}+\Phi _{s}+\Phi _{0}{\frac {\Delta \varphi ^{*}}{2\pi }}=n\Phi _{0}.}$

(27)

Without proof we state that the supercurrent through the weak link is given by the so-called DC Josephson relation^[12]

${\displaystyle i_{s}=i_{1}\sin(\Delta \varphi ^{*}).}$

(28)

The voltage over the contact is given by the AC Josephson relation

${\displaystyle V={\frac {1}{2\pi }}{\frac {h}{2e}}{\frac {\mathrm {d} \Delta \varphi ^{*}}{\mathrm {d} t}}.}$

(29)

The names of these relations (DC and AC relations) are misleading since they both hold in DC and AC situations. In the steady state (constant ${\displaystyle \Delta \varphi ^{*}}$) Eq. (29) shows that V=0 while a nonzero current flows through the junction. In the case of a constant applied voltage (voltage bias) Eq. (29) can be integrated easily and gives

${\displaystyle \Delta \varphi ^{*}=2\pi {\frac {2eV}{h}}t.}$

(30)

Substitution in Eq. (28) gives

${\displaystyle i_{s}=i_{1}\sin(2\pi {\frac {2eV}{h}}t).}$

(31)

This is an AC current. The frequency

${\displaystyle \nu ={\frac {2eV}{h}}={\frac {V}{\Phi _{0}}}}$

(32)

is called the Josephson frequency. One μV gives a frequency of about 500 MHz. By using Eq. (32) the flux quantum is determined with the high precision as given in Eq. (21).

The energy difference of a Cooper pair, moving from one side of the contact to the other, is ΔE = 2eV. With this expression Eq. (32) can be written as ΔE = hν which is the relation for the energy of a photon with frequency ν.

The AC Josephson relation (Eq. (29)) can be easily understood in terms of Newton's law, (or from one of the London equation's). We start with Newton's law

${\displaystyle {\vec {F}}=m\mathrm {d} {\vec {v}}_{s}/\mathrm {d} t.}$

Substituting the expression for the Lorentz force

${\displaystyle {\vec {F}}=q({\vec {E}}+{\vec {v}}_{s}\times {\vec {B}})}$

and using the general expression for the co-moving time derivative

${\displaystyle \mathrm {d} {\vec {v}}_{s}/\mathrm {d} t=\partial {\vec {v}}_{s}/\partial t+(1/2){\vec {\nabla }}v_{s}^{2}-{\vec {v}}_{s}\times ({\vec {\nabla }}\times {\vec {v}}_{s})}$

gives

${\displaystyle (q/m)({\vec {E}}+{\vec {v}}_{s}\times {\vec {B}})=\partial {\vec {v}}_{s}/\partial t+(1/2){\vec {\nabla }}v_{s}^{2}-{\vec {v}}_{s}\times ({\vec {\nabla }}\times {\vec {v}}_{s}).}$

Eq. (8) gives

${\displaystyle 0={\vec {\nabla }}\times {\vec {v}}_{s}+(q/m){\vec {\nabla }}\times {\vec {A}}={\vec {\nabla }}\times {\vec {v}}_{s}+(q/m){\vec {B}}}$

so

${\displaystyle (q/m){\vec {E}}=\partial {\vec {v}}_{s}/\partial t+(1/2){\vec {\nabla }}v_{s}^{2}.}$

Take the line integral of this expression. In the end points the velocities are zero so the ∇v² term gives no contribution. Using

${\displaystyle \int {\vec {E}}\cdot \mathrm {d} {\vec {l}}=-V}$

and Eq. (26), with q = −2e and m = 2m_e, gives Eq. (29).

DC SQUID

Main article: SQUID

 

Fig. 5. Two superconductors connected by two weak links. A current and a magnetic field are applied.

 

Fig. 6. Dependence of the critical current of a DC-SQUID on the applied magnetic field

Fig. 5 shows a so-called DC SQUID. It consists of two superconductors connected by two weak links. The fluxoid quantization of a loop through the two bulk superconductors and the two weak links demands

${\displaystyle \Delta \varphi _{a}^{*}=\Delta \varphi _{b}^{*}+2\pi {\frac {\Phi }{\Phi _{0}}}+2\pi n.}$

(33)

If the self-inductance of the loop can be neglected the magnetic flux in the loop Φ is equal to the applied flux

${\displaystyle \Phi =\Phi _{a}=BA}$

(34)

with B the magnetic field, applied perpendicular to the surface, and A the surface area of the loop. The total supercurrent is given by

${\displaystyle i_{s}=i_{1}\sin(\Delta \varphi _{a}^{*})+i_{1}\sin(\Delta \varphi _{b}^{*}).}$

(35)

Substitution of Eq(33) in (35) gives

${\displaystyle i_{s}=i_{1}\sin(\Delta \varphi _{b}^{*}+2\pi {\frac {\Phi }{\Phi _{0}}})+i_{1}\sin(\Delta \varphi _{b}^{*}).}$

(36)

Using a well known geometrical formula we get

${\displaystyle i_{s}=2i_{1}\sin(\Delta \varphi _{b}^{*}+\pi {\frac {\Phi }{\Phi _{0}}})\cos(\pi {\frac {\Phi _{a}}{\Phi _{0}}}).}$

(37)

Since the sin-function can vary only between −1 and +1 a steady solution is only possible if the applied current is below a critical current given by

${\displaystyle i_{c}=2i_{1}|\cos(\pi {\frac {\Phi _{a}}{\Phi _{0}}})|.}$

(38)

Note that the critical current is periodic in the applied flux with period Φ₀. The dependence of the critical current on the applied flux is depicted in Fig. 6. It has a strong resemblance with the interference pattern generated by a laser beam behind a double slit. In practice the critical current is not zero at half integer values of the flux quantum of the applied flux. This is due to the fact that the self-inductance of the loop cannot be neglected.

Type II superconductivity

Main article: Type-II superconductor

 

Fig. 7. Magnetic flux lines penetrating a type-II superconductor. The currents in the superconducting material generate a magnetic field which, together with the applied field, result in bundles of quantized flux.

Type-II superconductivity is characterized by two critical fields called B_c1 and B_c2. At a magnetic field B_c1 the applied magnetic field starts to penetrate the sample, but the sample is still superconducting. Only at a field of B_c2 the sample is completely normal. For fields in between B_c1 and B_c2 magnetic flux penetrates the superconductor in well-organized patterns, the so-called Abrikosov vortex lattice similar to the pattern shown in Fig. 2. A cross section of the superconducting plate is given in Fig. 7. Far away from the plate the field is homogeneous, but in the material superconducting currents flow which squeeze the field in bundles of exactly one flux quantum. The typical field in the core is as big as 1 tesla. The currents around the vortex core flow in a layer of about 50 nm with current densities on the order of 15×10¹² A/m². That corresponds with 15 million ampère in a wire of one mm².

Dilute quantum gases

The classical types of quantum systems, superconductors and superfluid helium, were discovered in the beginning of the 20th century. Near the end of the 20th century, scientists discovered how to create very dilute atomic or molecular gases, cooled first by laser cooling and then by evaporative cooling. They are trapped using magnetic fields or optical dipole potentials in ultrahigh vacuum chambers. Isotopes which have been used include rubidium (Rb-87 and Rb-85), strontium (Sr-87, Sr-86, and Sr-84) potassium (K-39 and K-40), sodium (Na-23), lithium (Li-7 and Li-6), and hydrogen (H-1). The temperatures to which they can be cooled are as low as a few nanokelvin. The developments have been very fast in the past few years. A team of NIST and the University of Colorado has succeeded in creating and observing vortex quantization in these systems. The concentration of vortices increases with the angular velocity of the rotation, similar to the case of superfluid helium and superconductivity.

Food safety

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Food_safety 

FDA lab tests seafood for microorganisms

 

Food safety
Terms
Foodborne illness Good manufacturing practice (GMP) Hazard analysis and critical control points (HACCP) Hazard analysis and risk-based preventive controls (HARPC) Critical control point
Critical factors
FAT TOM pH Water activity (aw)
Bacterial pathogens
Clostridium botulinum Escherichia coli Listeria Salmonella Vibrio cholerae Cronobacter spp
Viral pathogens
Enterovirus Hepatitis A Norovirus Rotavirus
Parasitic pathogens
Cryptosporidium Entamoeba histolytica Giardia Trichinella

Food safety (or food hygiene) is used as a scientific method/discipline describing handling, preparation, and storage of food in ways that prevent food-borne illness. The occurrence of two or more cases of a similar illness resulting from the ingestion of a common food is known as a food-borne disease outbreak. This includes a number of routines that should be followed to avoid potential health hazards. In this way, food safety often overlaps with food defense to prevent harm to consumers. The tracks within this line of thought are safety between industry and the market and then between the market and the consumer. In considering industry to market practices, food safety considerations include the origins of food including the practices relating to food labeling, food hygiene, food additives and pesticide residues, as well as policies on biotechnology and food and guidelines for the management of governmental import and export inspection and certification systems for foods. In considering market to consumer practices, the usual thought is that food ought to be safe in the market and the concern is safe delivery and preparation of the food for the consumer.

Food can transmit pathogens which can result in the illness or death of the person or other animals. The main types of pathogens are bacteria, viruses, mold, and fungus. Food can also serve as a growth and reproductive medium for pathogens. In developed countries there are intricate standards for food preparation, whereas in lesser developed countries there are fewer standards and less enforcement of those standards. Even so, here in the US, in 1999, 5,000 deaths per year were related to foodborne pathogens. Another main issue is simply the availability of adequate safe water, which is usually a critical item in the spreading of diseases. In theory, food poisoning is 100% preventable. However this cannot be achieved due to the number of persons involved in the supply chain, as well as the fact that pathogens can be introduced into foods no matter how many precautions are taken.

Issues

Food safety issues and regulations concern:

• Agriculture and animal husbandry practices
• Food manufacturing practices
• Food additives
• Novel foods
• Genetically modified foods
• Food label
• Food contamination

Food contamination

Food contamination happens when foods are corrupted with another substance. It can happen In the process of production, transportation, packaging, storage, sales, and cooking process. Contamination can be physical, chemical, or biological.

Physical contamination

Physical contaminants (or ‘foreign bodies’) are objects such as hair, plant stalks or pieces of plastic and metal. When a foreign object enters food, it is a physical contaminant. If the foreign objects are bacteria, both a physical and biological contamination will occur.

Common sources of physical contaminations are: hair, glass or metal, pests, jewelry, dirt, and fingernails.

Chemical contamination

Chemical contamination happens when food is contaminated with a natural or artificial chemical substance. Common sources of chemical contamination can include: pesticides, herbicides, veterinary drugs, contamination from environmental sources (water, air or soil pollution), cross-contamination during food processing, migration from food packaging materials, presence of natural toxins, or use of unapproved food additives and adulterants.

Biological contamination

It happens when the food has been contaminated by substances produced by living creatures, such as humans, rodents, pests or microorganisms. This includes bacterial contamination, viral contamination, or parasite contamination that is transferred through saliva, pest droppings, blood or fecal matter. Bacterial contamination is the most common cause of food poisoning worldwide. If an environment is high in starch or protein, water, oxygen, has a neutral pH level, and maintains a temperature between 5°C and 60°C (danger zone) for even a brief period of time (~0–20 minutes), bacteria are likely to survive.

Example of biological contamination: Tainted Romaine Lettuce

In April and May 2018, 26 states in the United States suffered an outbreak of the bacteria strain E. coli O157:H7. Several investigations show the contamination might have come from the Yuma, Arizona, growing region. This outbreak, which began April 10, is the largest US flare-up of E. coli in a decade. One person in California died. At least 14 of the people affected developed kidney failure. The most common symptoms of E. coli include diarrhea, bloody diarrhea, abdominal pain, nausea and vomiting.

Safe food handling procedures (from market to consumer)

The five key principles of food hygiene, according to WHO, are:

1. Prevent contaminating food with pathogens spreading from people, pets, and pests.
2. Separate raw and cooked foods to prevent contaminating the cooked foods.
3. Cook foods for the appropriate length of time and at the appropriate temperature to kill pathogens.
4. Store food at the proper temperature.
5. Use safe water and safe raw materials.

Proper storage, sanitary tools and work spaces, heating and cooling properly and to adequate temperatures, and avoiding contact with other uncooked foods can greatly reduce the chances of contamination. Tightly sealed water and air proof containers are good measures to limit the chances of both physical and biological contamination during storage. Using clean, sanitary surfaces and tools, free of debris, chemicals, standing liquids, and other food types (different than the kind currently being prepared, i.e. mixing vegetables/meats or beef/poultry) can help reduce the chance of all forms of contamination. However, even if all precautions have been taken and the food has been safely prepared and stored, bacteria can still form over time during storage. Food should be consumed within one to seven (1-7) days while it has been stored in a cold environment, or one to twelve (1-12) months if it was in a frozen environment (if it was frozen immediately after preparation). The length of time before a food becomes unsafe to eat depends on the type of food it is, the surrounding environment, and the method with which it is kept out of the danger zone.

• Always refrigerate perishable food within 2 hours—1 hour when the temperature is above 90°F (32.2°C).
• Check the temperature of your refrigerator and freezer with an appliance thermometer. The refrigerator should be at 40°F (4.4°C) or below and the freezer at 0°F (-17.7°C) or below.

For example, liquid foods like soup kept in a hot slow cooker (149°F or 65°C) may last only a few hours before contamination, but fresh meats like beef and lamb that are promptly frozen (-2°C) can last up to a year. The geographical location can also be a factor if it is in close proximity to wildlife. Animals like rodents and insects can infiltrate a container or prep area if left unattended. Any food that has been stored while in an exposed environment should be carefully inspected before consuming, especially if it was at risk of being in contact with animals. Consider all forms of contamination when deciding if a food is safe or unsafe, as some forms or contamination will not leave any apparent signs. Bacteria may not be visible to the naked eye, debris (physical contamination) may be underneath the surface of a food, and chemicals may be clear or tasteless; the contaminated food may not change in smell, texture, appearance, or taste, and could still be contaminated. Any foods deemed contaminated should be disposed of immediately, and any surrounding food should be checked for additional contamination.

ISO 22000 is a standard developed by the International Organization for Standardization dealing with food safety. This is a general derivative of ISO 9000. The ISO 22000 international standard specifies the requirements for a food safety management system that involves interactive communication, system management, prerequisite programs, HACCP principles. ISO 22000 was first published in 2005. It is the culmination of all previous attempts from many sources and areas of food safety concern to provide an end product that is safe as possible from pathogens and other contaminants. Every 5 years standards are reviewed to determine whether a revision is necessary, to ensure that the standards remain as relevant and useful to businesses as possible.

Incidence

World Health Organization

A 2003 World Health Organization (WHO) report concluded that about 30% of reported food poisoning outbreaks in the WHO European Region occur in private homes. According to the WHO and CDC, in the USA alone, annually, there are 76 million cases of foodborne illness leading to 325,000 hospitalizations and 5,000 deaths.

Regulations by jurisdiction and agency

WHO and FAO

In 1963, the WHO and FAO published the Codex Alimentarius which serves as an guideline to food safety.

However, according to Unit 04 - Communication of Health & Consumers Directorate-General of the European Commission (SANCO): "The Codex, while being recommendations for voluntary application by members, Codex standards serve in many cases as a basis for national legislation. The reference made to Codex food safety standards in the World Trade Organizations' Agreement on Sanitary and Phytosanitary measures (SPS Agreement) means that Codex has far reaching implications for resolving trade disputes. WTO members that wish to apply stricter food safety measures than those set by Codex may be required to justify these measures scientifically." So, an agreement made in 2003, signed by all member states, inclusive all EU, in the codex Stan Codex 240 – 2003 for coconut milk, sulphite containing additives like E223 and E 224 are allowed till 30 mg/kg, does NOT mean, they are allowed into the EU, see Rapid Alert System for Food and Feed (RASFF) entries from Denmark: 2012.0834; 2011.1848; en 2011.168, "sulphite unauthorised in coconut milk from Thailand ". Same for polysorbate E 435: see 2012.0838 from Denmark, unauthorised polysorbates in coconut milk and, 2007.AIC from France. Only for the latter the EU amended its regulations with (EU) No 583/2012 per 2 July 2012 to allow this additive, already used for decades and absolutely necessary.

Australia

Main article: Food safety in Australia

Food Standards Australia New Zealand requires all food businesses to implement food safety systems. These systems are designed to ensure food is safe to consume and halt the increasing incidence of food poisoning, and they include basic food safety training for at least one person in each business. Food safety training is delivered in various forms by, among other organisations, Registered Training Organisations (RTOs), after which staff are issued a nationally recognised unit of competency code on their certificate. Basic food safety training includes:

• Understanding the hazards associated with the main types of food and the conditions to prevent the growth of bacteria which can cause food poisoning and to prevent illness.
• Potential problems associated with product packaging such as leaks in vacuum packs, damage to packaging or pest infestation, as well as problems and diseases spread by pests.
• Safe food handling. This includes safe procedures for each process such as receiving, re-packing, food storage, preparation and cooking, cooling and re-heating, displaying products, handling products when serving customers, packaging, cleaning and sanitizing, pest control, transport and delivery. Also covers potential causes of cross contamination.
• Catering for customers who are particularly at risk of food-borne illness, as well as those with allergies or intolerance.
• Correct cleaning and sanitizing procedures, cleaning products and their correct use, and the storage of cleaning items such as brushes, mops and cloths.
• Personal hygiene, hand washing, illness, and protective clothing.

Food safety standards and requirements are set out at the national level in the Food Standards Code, and brought into force in each state and territory by state-based Acts and Regulations. Legislation means that people responsible for selling or serving unsafe food may be liable for heavy fines.

China

Main article: Food safety in China

Food safety is a growing concern in Chinese agriculture. The Chinese government oversees agricultural production as well as the manufacture of food packaging, containers, chemical additives, drug production, and business regulation. In recent years, the Chinese government attempted to consolidate food regulation with the creation of the State Food and Drug Administration in 2003, and officials have also been under increasing public and international pressure to solve food safety problems. However, it appears that regulations are not well known by the trade. Labels used for "green" food, "organic" food and "pollution-free" food are not well recognized by traders and many are unclear about their meaning. A survey by the World Bank found that supermarket managers had difficulty in obtaining produce that met safety requirements and found that a high percentage of produce did not comply with established standards.

Traditional marketing systems, whether in China or the rest of Asia, presently provide little motivation or incentive for individual farmers to make improvements to either quality or safety as their produce tends to get grouped together with standard products as it progresses through the marketing channel. Direct linkages between farmer groups and traders or ultimate buyers, such as supermarkets, can help avoid this problem. Governments need to improve the condition of many markets through upgrading management and reinvesting market fees in physical infrastructure. Wholesale markets need to investigate the feasibility of developing separate sections to handle fruits and vegetables that meet defined safety and quality standards.

European Union

The parliament of the European Union (EU) makes legislation in the form of directives and regulations, many of which are mandatory for member states and which therefore must be incorporated into individual countries' national legislation. As a very large organisation that exists to remove barriers to trade between member states, and into which individual member states have only a proportional influence, the outcome is often seen as an excessively bureaucratic 'one size fits all' approach. However, in relation to food safety the tendency to err on the side of maximum protection for the consumer may be seen as a positive benefit. The EU parliament is informed on food safety matters by the European Food Safety Authority.

Individual member states may also have other legislation and controls in respect of food safety, provided that they do not prevent trade with other states, and can differ considerably in their internal structures and approaches to the regulatory control of food safety.

From 13 December 2014, new legislation - the EU Food Information for Consumers Regulation 1169/2011 - require food businesses to provide allergy information on food sold unpackaged, in for example catering outlets, deli counters, bakeries and sandwich bars. A further addition to the 2014 legislation, named 'Natasha's Law' will come into force on 1st October in the UK and NI. Following the death of Natasha Ednan-Laperouse, who tragically lost her life after eating a sandwich containing the allergen sesame, foods pre-packed on premises for direct sale will require individual ingredients labelling - this replaces the historic requirement for outlets to provide ingredients information for these types of food upon request. 

France

Agence nationale de sécurité sanitaire de l'alimentation, de l'environnement et du travail (ANSES) is a French governmental agency dealing with food safety.

Germany

The Federal Ministry of Food, Agriculture and Consumer Protection (BMEL) is a Federal Ministry of the Federal Republic of Germany. History: Founded as Federal Ministry of Food, Agriculture and Foresting in 1949, this name did not change until 2001. Then the name changed to Federal Ministry of Consumer Protection, Food and Agriculture. At 22 November 2005, the name got changed again to its current state: Federal Ministry of Food, Agriculture and Consumer Protection. The reason for this last change was that all the resorts should get equal ranking which was achieved by sorting the resorts alphabetically. Vision: A balanced and healthy diet with safe food, distinct consumer rights and consumer information for various areas of life, and a strong and sustainable agriculture as well as perspectives for our rural areas are important goals of the Federal Ministry of Food, Agriculture and Consumer Protection (BMELV). The Federal Office of Consumer Protection and Food Safety is under the control of the Federal Ministry of Food, Agriculture and Consumer Protection. It exercises several duties, with which it contributes to safer food and thereby intensifies health-based consumer protection in Germany. Food can be manufactured and sold within Germany without a special permission, as long as it does not cause any damage on consumers’ health and meets the general standards set by the legislation. However, manufacturers, carriers, importers and retailers are responsible for the food they pass into circulation. They are obliged to ensure and document the safety and quality of their food with the use of in-house control mechanisms.

Greece

In Greece, the Hellenic Food Authority (EFET) governing body supervised by the Ministry of the Environment and Energy (Greek: Υπουργείο Περιβάλλοντος και Ενέργειας), it is in charge of ensuring food sold is safe and fit for consumption. It controls the food business operators including agricultural producers, food processors, retailers, caterers, input material suppliers and private laboratories.

Hong Kong

In Hong Kong SAR, the Food and Environmental Hygiene Department is in charge of ensuring food sold is safe and fit for consumption.

Hungary

In Hungary, the National Food Chain Safety Office controls the food business operators including agricultural producers, food processors, retailers, caterers, input material suppliers and private laboratories. Its activities also cover risk assessment, risk communication and related research.

India

Food Safety and Standards Authority of India, established under the Food Safety and Standards Act, 2006, is the regulating body related to food safety and laying down of standards of food in India.

New Zealand

See also: Food safety in New Zealand

The New Zealand Food Safety Authority (NZFSA), or Te Pou Oranga Kai O Aotearoa is the New Zealand government body responsible for food safety. NZFSA is also the controlling authority for imports and exports of food and food-related products. The NZFSA as of 2012 is now a division of the Ministry for Primary Industries (MPI) and is no longer its own organization.

Pakistan

The Pure Food Ordinance 1960 consolidates and amends the law in relation to the preparation and the sale of foods. Its aim is to ensure purity of food being supplied to people in the market and, therefore, provides for preventing adulteration.

Pakistan Hotels and Restaurant Act, 1976 applies to all hotels and restaurants in Pakistan and seeks to control and regulate the standard of service(s) by hotels and restaurants. In addition to other provisions, under section 22(2), the sale of food or beverages that are contaminated, not prepared hygienically or served in utensils that are not hygienic or clean is an offense.

South Korea

Korea Food & Drug Administration

Korea Food & Drug Administration (KFDA) is working for food safety since 1945. It is part of the Government of South Korea.

IOAS-Organic Certification Bodies Registered in KFDA: "Organic" or related claims can be labelled on food products when organic certificates are considered as valid by KFDA. KFDA admits organic certificates which can be issued by 1) IFOAM (International Federation of Organic Agriculture Movement) accredited certification bodies 2) Government accredited certification bodies – 328 bodies in 29 countries have been registered in KFDA.

Food Import Report: According to Food Import Report, it is supposed to report or register what you import. Competent authority is as follows:

Product	Authority
Imported Agricultural Products, Processed Foods, Food Additives, Utensils, Containers & Packages or Health Functional Foods	KFDA (Korea Food and Drug Administration)
Imported Livestock, Livestock products (including Dairy products)	NVRQS (National Veterinary Research and Quarantine Service)
Packaged meat, milk & dairy products (butter, cheese), hamburger patties, meat ball and other processed products which are stipulated by Livestock Sanitation Management Act	NVRQS (National Veterinary Research and Quarantine Service)
Imported Marine products; fresh, chilled, frozen, salted, dehydrated, eviscerated marine produce which can be recognized its characteristics	NFIS (National Fisheries Products Quality Inspection Service)

National Institute of Food and Drug Safety Evaluation

National Institute of Food and Drug Safety Evaluation (NIFDS) is functioning as well. The National Institute of Food and Drug Safety Evaluation is a national organization for toxicological tests and research. Under the Korea Food & Drug Administration, the Institute performs research on toxicology, pharmacology, and risk analysis of foods, drugs, and their additives. The Institute strives primarily to understand important biological triggering mechanisms and improve assessment methods of human exposure, sensitivities, and risk by (1) conducting basic, applied, and policy research that closely examines biologically triggering harmful effects on the regulated products such as foods, food additives, and drugs, and operating the national toxicology program for the toxicological test development and inspection of hazardous chemical substances assessments. The Institute ensures safety by investigation and research on safety by its own researchers, contract research by external academicians and research centers.

Taiwan

In Taiwan, the Ministry of Health and Welfare in charge of Food and Drug Safety, also evaluate the catering industry to maintenance the food product quality. Currently, US $29.01 million budget is allocated each year for food safety-related efforts.

Turkey

In Turkey, the Ministry of Agriculture and Forestry, is in charge of food safety and they provide their mission as "to ensure access to safe food and high-quality agricultural products needed by Turkey and world markets" among other responsibilities. The institution itself has research and reference laboratories across the country helping the control and inspection of food safety as well as reviewing and updating the current regulations and laws about food safety constantly.

United Kingdom

In the UK the Food Standards Agency is an independent government department responsible for food safety and hygiene across the UK. They work with businesses to help them produce safe food, and with local authorities to enforce food safety regulations. In 2006 food hygiene legislation changed and new requirements came into force. The main requirement resulting from this change is that anyone who owns or run a food business in the UK must have a documented Food Safety Management System, which is based on the principles of Hazard Analysis Critical Control Point HACCP. Furthermore, according to UK legislation, food handlers and their supervisors must be adequately trained in food safety. Although food handlers are not legally obliged to hold a certificate they must be able to demonstrate to a health officer that they received training on the job, have prior experience, and have completed self-study. In practice, the self-study component is covered via a Food Hygiene & Safety certificate. Common occupations which fall under this obligation are Nannys, childminders, teachers, food manufacturers, chefs, cooks and catering staff. 

In early 2019, as part of US-UK negotiations to arrive at a trade deal prior to Brexit, the Trump administration asked the UK to eliminate its existing ban on chlorinated chicken, genetically modified plants and hormone-injected beef, products that the US would like to sell in the UK.

United States

Main article: Food safety in the United States

 

US FDA scientist tests for Salmonella

The US food system is regulated by numerous federal, state and local officials. Since 1906 tremendous progress has been made in producing safer foods as can be seen in the section below. Still, it has been criticized as lacking in "organization, regulatory tools, and not addressing food borne illness."

Federal level regulation

The Food and Drug Administration (FDA) publishes the Food Code, a model set of guidelines and procedures that assists food control jurisdictions by providing a scientifically sound technical and legal basis for regulating the retail and food service industries, including restaurants, grocery stores and institutional foodservice providers such as nursing homes. Regulatory agencies at all levels of government in the United States use the FDA Food Code to develop or update food safety rules in their jurisdictions that are consistent with national food regulatory policy. According to the FDA, 48 of 56 states and territories, representing 79% of the US population, have adopted food codes patterned after one of the five versions of the Food Code, beginning with the 1993 edition.

In the United States, federal regulations governing food safety are fragmented and complicated, according to a February 2007 report from the Government Accountability Office. There are 15 agencies sharing oversight responsibilities in the food safety system, although the two primary agencies are the US Department of Agriculture (USDA) Food Safety and Inspection Service (FSIS), which is responsible for the safety of meat, poultry, and processed egg products, and the FDA, which is responsible for virtually all other foods.

The Food Safety and Inspection Service has approximately 7,800 inspection program personnel working in nearly 6,200 federally inspected meat, poultry and processed egg establishments. FSIS is charged with administering and enforcing the Federal Meat Inspection Act, the Poultry Products Inspection Act, the Egg Products Inspection Act, portions of the Agricultural Marketing Act, the Humane Slaughter Act, and the regulations that implement these laws. FSIS inspection program personnel inspect every animal before slaughter, and each carcass after slaughter to ensure public health requirements are met. In fiscal year (FY) 2008, this included about 50 billion pounds of livestock carcasses, about 59 billion pounds of poultry carcasses, and about 4.3 billion pounds of processed egg products. At US borders, they also inspected 3.3 billion pounds of imported meat and poultry products.

US legislation history

FDA official inspecting a candy factory c. 1911

Recognition of food safety issues and attempts to address them began after Upton Sinclair published the novel The Jungle in 1906. It was a fictional account of the lives of immigrants in the industrial cities in the US around this time. Sinclair spent nine months undercover as an employee in a Chicago meat plant doing research. The book inadvertently raised public concern about food safety and sanatization of the Chicago meat packing industry. Upon reading The Jungle, President Theodore Roosevelt called on Congress to pass the Pure Food and Drug Act and the Federal Meat Inspection Act (FMIA), which passed in 1906 and 1907 respectively. These laws were the first to address food safety in the US Misbranding and adulteration were defined as they concerned food additives and truth in labeling. Food preservatives such as formaldehyde and borax used to disguise unsanitary production processes were also addressed.

The first test and major court battle involving the Pure Food and Drug Act was United States v. Forty Barrels & Twenty Kegs of Coca-Cola, an attempt to outlaw Coca-Cola due to its excessive caffeine content. The Meat Inspection Act led to the formation of the Food and Drug Administration (FDA). Between 1906 and 1938, acts were created that monitored food coloration additives, and other chemical additives such as preservatives, as well as food labeling and food marketing.

During the winter of 1924–1925, the worst food-borne illness to date in the US occurred because of improper handling of oysters. This produced a typhoid fever epidemic, and food-borne illness outbreaks gained national attention. Unfortunately, it was not until 1969 that the FDA began sanitization programs specifically for shellfish and milk, and began its focus and implementation on the food service industry as a whole.

In 1970 the Center for Disease Control (CDC) began keeping records on food-borne illness deaths. This was the beginning of effective record keeping that could be used to control and prevent similar outbreaks in the future. The first major food recall in the US was caused by canned mushrooms in 1973. This outbreak of botulism produced the National Botulism Surveillance System. This system collected the data on all confirmed cases of botulism in the US This led to processing regulations for low-acid foods to ensure proper heat treating of canned foods. The Jack in the Box E. coli outbreak of 1993 led the Clinton administration to put $43 million into the Food Safety Initiative to create many of the common specific regulations in place today. This initiative produced regulations on seafood, meat, poultry, and shell-eggs. This initiative produced a program for DNA fingerprinting to help track outbreaks and to determine their source. It also called for a cooperative detection and response effort between the CDC, FDA, USDA and local agencies called FoodNet.

In 2011 the Food Safety Modernization Act (FSMA) produced what is considered the most significant food safety legislation in over 70 years. The significant difference between this and previous acts was that it shifted to focus from response and containment of food-borne disease outbreaks to their prevention. This act is still in the early implementation phase but gives the FDA authority to regulate the way foods are grown, processed, and harvested.

Industry pressure

There have been concerns over the efficacy of safety practices and food industry pressure on US regulators. A study reported by Reuters found that "the food industry is jeopardizing US public health by withholding information from food safety investigators or pressuring regulators to withdraw or alter policy designed to protect consumers". A 2010 survey found that 25% of US government inspectors and scientists surveyed had experienced during the past year corporate interests forcing their food safety agency to withdraw or to modify agency policy or action that protects consumers. Scientists observed that management undercuts field inspectors who stand up for food safety against industry pressure. According to Dr. Dean Wyatt, a USDA veterinarian who oversees federal slaughterhouse inspectors, "Upper level management does not adequately support field inspectors and the actions they take to protect the food supply. Not only is there lack of support, but there's outright obstruction, retaliation and abuse of power." A growing number of food and beverage manufacturers are improving food safety standards by incorporating a food safety management system which automates all steps in the food quality management process.

State and local regulation

FDA official and New Jersey state inspector review harvest of clams

A number of US states have their own meat inspection programs that substitute for USDA inspection for meats that are sold only in-state. Certain state programs have been criticized for undue leniency to bad practices. Contrastingly, there are some state-level programs that supplement Federal inspections rather than replacing them. Said programs generally operate with the goal of increasing consumer confidence in their state's produce, play a role in investigating outbreaks of food-borne disease bacteria- such as in the 2006 outbreak of pathogenic Escherichia coli O157:H7- and promote better food processing practices to eliminate food-borne threats. Additionally, several states which are major producers of fresh fruits and vegetables (including California, Arizona and Florida) have their own state programs to test produce for pesticide residues.

The food system represents one of the most significant components of the U.S. economy. It affects the social and economic well-being of nearly all Americans and plays a significant role in the well-being of the global community. The U.S. food and fiber system accounted for 18 percent of employment 4 percent of imported goods, and 11 percent of exports in 2011. The relative economic contribution of each various step of the U.S. food supply chain has changed significantly over the past 100 years. Generally speaking, the economic importance of the farm production subsector has steadily diminished relative to the shares of the other components of the food supply chain.

Restaurants and other retail food establishments fall under state law and are regulated by state or local health departments. Typically these regulations require official inspections of specific design features, best food-handling practices, and certification of food handlers. In some places a letter grade or numerical score must be prominently posted following each inspection. In some localities, inspection deficiencies and remedial action are posted on the Internet. In addition, states may maintain and enforce their own model of the FDA Food Code. For example, California maintains the California Retail Food Code (CalCode), which is part of the Health and Safety Code and is based on most current and safe food handling practices in the retail industry. It has been argued that restaurant hygiene ratings, though useful at times, are not informative enough for consumers.

Vietnam

The Vietnam Food Administration is reafor managing food hygiene, safety, and quality and has made significant progress since its establishment in 1999. Food safety remains a high priority in Vietnam with the growth of export markets and increasing food imports raising the need to rapidly build capacity of the Food Administration in order to reduce threats of foodborne disease. The Food Administration has demonstrated commitment to the food safety challenges it faces, and has embarked on an innovative capacity building activity with technical assistance from the World Health Organization.

Manufacturing control

HACCP guidelines

Meat and Poultry manufacturers are required to have a HACCP plan in accordance with 9 CFR part 417.

Juice manufacturers are required to have a HACCP plan in accordance with 21 CFR part 120.

Seafood manufacturers are required to have a HACCP plan in accordance with 21 CFR part 123.

Consumer labeling

Main article: List of food labeling regulations

United Kingdom

Foodstuffs in the UK have one of two labels to indicate the nature of the deterioration of the product and any subsequent health issues. EHO Food Hygiene certification is required to prepare and distribute food. While there is no specified expiry date of such a qualification the changes in legislation it is suggested to update every five years.

Best before indicates a future date beyond which the food product may lose quality in terms of taste or texture amongst others, but does not imply any serious health problems if food is consumed beyond this date (within reasonable limits).

Use by indicates a legal date beyond which it is not permissible to sell a food product (usually one that deteriorates fairly rapidly after production) due to the potential serious nature of consumption of pathogens. Leeway is sometimes provided by producers in stating display until dates so that products are not at their limit of safe consumption on the actual date stated (this latter is voluntary and not subject to regulatory control). This allows for the variability in production, storage and display methods.

United States

With the exception of infant formula and baby foods which must be withdrawn by their expiration date, Federal law does not require expiration dates. For all other foods, except dairy products in some states, freshness dating is strictly voluntary on the part of manufacturers. In response to consumer demand, perishable foods are typically labelled with a Sell by date. It is up to the consumer to decide how long after the Sell by date a package is usable. Other common dating statements are Best if used by, Use-by date, Expiration date, Guaranteed fresh date, and Pack date. When used, freshness dating must be validated using AOAC guidelines. Although this dating requires product testing throughout the entire timeframe, accelerated shelf life testing, using elevated temperatures and humidity, can be used to determine shelf life before the long-term results can be completed.

Australia and New Zealand

Guide to Food Labelling and Other Information Requirements: This guide provides background information on the general labelling requirements in the Code. The information in this guide applies both to food for retail sale and to food for catering purposes. Foods for catering purposes means those foods for use in restaurants, canteens, schools, caterers or self-catering institutions, where food is offered for immediate consumption. Labelling and information requirements in the new Code apply both to food sold or prepared for sale in Australia and New Zealand and food imported into Australia and New Zealand. Warning and Advisory Declarations, Ingredient Labelling, Date Marking, Nutrition Information Requirements, Legibility Requirements for Food Labels, Percentage Labelling, Information Requirements for Foods Exempt from Bearing a Label.