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An alphabetical glossary of technical terms used on the site.


Changing a process, like food manufacturing or fermentation, to produce much larger amounts of the final product.


A mental disorder caused by brain dysfunction, resulting in hallucinations, delusions and distorted thinking.


A sudden attack, convulsion, spasm or sensation.

Selection pressure

An external feature that changes the traits an organism needs to survive and reproduce.

Selective breeding

A human-controlled breeding programme in which specific plants or animals are chosen to breed (produce offspring) because they have particularly useful or valuable features. The aim is to produce offspring with specific characteristics.

Sensory testing

Testing a new product for its sensory effects, such as smell, taste and texture.


A person or animal used to watch over or keep guard.


An infection in the blood.


Testing for the presence of antibodies to pathogens, such as viruses or bacteria, as evidence of past infection.

Serving size

The portion (or amount) of food used as a reference on food labels. It tends to be based on the average amount eaten in one sitting.

Severe combined immunodeficiency syndrome

A disorder of the immune system, which makes patients more likely to get infections.

Shelf life

The length of time food, drink and other perishable items are considered suitable for consumption.

Short tandem repeat (STR)

A short DNA sequence (from 2-5 nucleotides) that is repeated multiple times. Short tandem repeats can be used to get a DNA profile.


High-moisture feed for livestock that is made from crops fermented anaerobically (without air) and can be stored over winter.

Single nucleotide polymorphism (SNP)

A difference of one nucleotide of a DNA sequence.


A continuous strand of loose fibres.

Sloppy PCR

A version of polymerase chain reaction (PCR) in which changes in DNA sequence are introduced.

Small interfering RNA (siRNA)

A small, double stranded RNA molecule that binds to complementary DNA sequences and prevents gene expression. Also called short interfering RNA or silencing RNA.

Soluble fibre

Fibre that is almost completely broken down by bacteria in the large intestine.


A substance that can dissolve another substance, for example, water or ethanol.

Somatic cell

Any cell in a plant or animal that is not a gamete (in a germ cell or sex cell).


Juvenile mussels that have recently settled onto seaweed and other surfaces. Spat is also used to describe juveniles of other bivalves, such as oysters.


The act of reproduction of fishes. The mixing of the sperm of a male fish and the eggs of a female fish.


The laying of eggs by aquatic animals like fish or frogs.

Specialised cells

A cell that has altered so it can perform a specific function in a multicellular organism.


The process by which new distinct species evolve.


A group of living organisms that can interbreed to produce viable offspring.


An instrument for measuring light intensity as a function of the wavelength of light. For quantifying DNA, the amount of UV radiation absorbed by the bases present in a fixed amount of sample is determined.

Spinal cord

A bundle of nerves that runs through the backbone. The nerves process information and conduct impulses between the brain and the rest of the body.


The reproductive part of some plants and fungi (instead of a seed), which can develop into an organism.


Saliva or spit, sometimes used to diagnose disease.


The male organ in a flower that produces pollen.


A complex carbohydrate commonly found in foods, such as potatoes, wheat, rice and corn.

Statistically significant difference

A mathematical term that indicates that the difference between two (or more) results is greater than the difference you might expect due to chance.

Stem cell

A cell that has the potential to become any of the specialised cell types that make up an organism.


Free from contaminating organisms, like bacteria or viruses, that may transmit disease.


The female organ in a flower.


In microbiology, a subtype of a species of microorganism.


When part of the brain is damaged due to its blood supply being reduced or stopped.

Stud ram

A male sheep that is selected in a breeding programme to father lots of lambs because of its desirable physical or genetic characteristics.


A bacteria that is resistant to treatment with antibiotics.


The liquid layer that remains after a solution is spun in a centrifuge.


When a solution contains a substance at a very high concentration.

Supply chain

All of the steps needed to take a basic material and turn it into a finished product ready for sale.


A chemical that stabilises mixtures of oil and water.


An increased chance of being affected by something, for example, a disease.


A way of using natural products so they are available for future generations.


A close relationship between two organisms, which is usually beneficial to both.


A compound that enhances the effect of another compound.


The working together of two things (food components, for example) to produce an effect greater than the sum of their individual effects.


Made in a laboratory or factory by a chemical process, usually to imitate a natural process.

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