any substance not intentionally added to food which is presented in such food as a result of the production (including operations carried out in crop husbandry, animal husbandry and veterinary medicine), manufacture, processing, preparation, treatment, packing, transport or holding of such food, or as a result of environmental contamination” 

residue of substances having a pharmacological action, of their metabolites and of other substances transmitted to animal products and likely to be harmful to human health 

No-Observed-Effect Level (NOEL),

◦ Acceptable Daily Intake (ADI),
◦ Tolerable Daily Intake (TDI)
◦ Maximum Residue Limits (MRLs),

◦ Detection Limit 

 Calculation of the ADI depends on the toxicology of the compound and its NOEL,

 Toxicology effects are determinate by acute and chronic studies involving genotoxicity, carcinogenicity, mutogenicity, etc... effects. 

- The maximum concentration of residue (expressed in mg/kg or μg/kg on a fresh weight basis) which may be accepted by the European Community to be legally permitted or recognized as acceptable in or on a food,

 It is based on the type and amount of residue considered to be without any toxicological hazard for human health as expressed by the ADI that utilizes an additional safety factor. It also takes into account other relevant public health risks as well as food technology aspects. 

The withdrawal period is the time which passes between the administration of the last dose of a medicine and the time when the level of residues in the tissues or products falls below the MRL,

 Medicine withdrawal period must be observed at all times,

 An animal or its products must not be sold for human consumption before the withdrawal period has been elapsed. 

Meat from poultry and mammals: 28 days,
◦ Meat from fish: 500 degrees day (i.e. 50 days at 10C)

◦ Milk: 7 days,
◦ Eggs: 7 days. 

Analyte - a substance in a test sample, the presence of which has to be detected and/or quantified,

 Detection Limit - the smallest analyte concentration for which a method has been validated with specified accuracy and precision (sensitivity and specificity of the device). 

- The Contaminants in Food (Scotland) Regulations 2005 ( sets max levels for contaminants in food) 

- The Animals and Animal products Regulations 1997 ( limits of vet med products in food, 

◦ The FSA collect red meat and poultry meat samples from carcasses at slaughterhouses,

◦ The APHA Office, collect samples from live animals, animal feed and milk from farms,

◦ CEFAS collect salmon and trout samples from fish farms in England & Wales; and Fisheries Research Services collect samples from fish farms in Scotland,

◦ Defra’s Egg Marketing Inspectors (EMIs) collect egg samples from packing stations in England & Wales,

◦ The Scottish Office Egg Marketing Officers (EMOs) do the same in Scotland,

◦ In Northern Ireland, their Department of Agriculture’s officers collect the samples. 

The Veterinary Medicines Directorate (VMD) is responsible for the co-ordination and management of the UK programme and for the management and operation of the National Surveillance Scheme (NSS) in GB.

 To fulfil GB’s obligation VMD will then request monthly samples from individual slaughterhouses and farms.

 FSA and APHA officers collect samples as per VMD requirement. 

VMD will request different samples (liver, kidney, muscle, milk, fat, blood, serum) based on:

◦ Pharmacokinetic of the Residue

◦ Type of lab test to carry out

 Collection of manure, urine, blood, hair samples at the farm can be used to monitor prohibited substances prior to slaughter. 

ex. lead-> test liver sample

ab-> urine and kidney sample 

Selection of animals in the lairage:

◦ Random: not from same producer, not from same animal, not same day, ensure in one year the OV tests as many different farm and animals as possible for different residues.

◦ Suspect: the OV suspects or has evidence that animals have been treated with unauthorised substances or may contain residues of authorised substances above the MRL. Casualty animals should be always considered for testing. 

Collection of samples:

◦ Promptly: (i.e. at sticking point for blood or at evisceration for urine); avoid cross contamination from personnel/tools and to meat,

◦ Keep traceability: (i.e. farmer, sample and paperwork),

• Keep Security: (i.e. not tampered with),

• Proper storage: (i.e. depending on the

type of sample)

◦ Dispatch 

Sample stored in a cold-box (e.g. dry ice) or a freezer and protected from light:

◦ Sulphadimidine residues decreases during storage

• Furazolidone is rapidly degraded post mortem

• Penicillin is sensitive to thermal degradation

• Chloramphenicol is rapidly degraded in liver 

screening: samples are screened for the presence of residues. Any sample found “positive” at this stage is subjected to confirmatory analysis,

◦ confirmation: very sensitive and selective methods identify the residue and measure its concentration. 

Where high concentrations of authorised substances or unauthorised substances are detected, what happens? 

an investigation will be undertaken by an Investigation Officer from Defra’s Legal Department. The VMD may prosecute if there is sufficient evidence of misuse of an authorised product, or use of an unauthorised substance, 

NON-STATUTORY SURVEILLANCE SCHEME 

- at border inspection points 

The Non-Statutory Surveillance Scheme mainly looks for the use of banned or unauthorised substances in imported meat, farmed fish and honey. The surveillance is funded by Defra and carried out at Border Inspection Posts.

◦ In the course of the year, intelligence is received from the Rapid Alert System for Food and Feed (RASFF) and other sources from which trends can be identified. 

- are the very small amounts of veterinary medicines that can remain in animal products, such as meat, fish, eggs, honey and milk, after slaughter or collection, and so make their way into the food chain.

 Veterinary medicines remaining in the animal products must not be harmful to people eating the products. This process takes account of any risk to babies and children. 

Usually the neck or rump, but can be found on every

part of a carcass,

◦ Area of discoloration or bruising,

◦ Swelling and yellowish part of the carcasses, lack of symmetry in the muscle (at incision oily adjuvant material),

- hard, fibrous nodules in the muscles

- smell ( especially tetracycline) 

◦ Typically are at very low concentrations,

◦ Metabolites of the parent drug with possible unknown pharmacokinetics. 

If the FBO voluntary surrender the carcass, proceed to dispose of it as Cat. 2 material.

◦ If the FBO doesn’t voluntary surrender the carcass proceed with collection of samples to send to the laboratory. 

If there is no evidence of residue in the carcass and with written evidence of the withdrawal period being observed...

trim the affected part of the carcass and release the rest for human consumption. 

Substances having anabolic effects and unauthorized substances,

 Residues in food of drugs which are toxic or have side effects in humans are unacceptable,

 Antibiotics: peptides (avoparcin, virginiamycin, zinc bacitracin), sulphonamid (dapson), chloramphenicol,

 Fungicide: malachite green,

 Coccidiostats: nitroimidazoles (dimetridazole, ronidazole, metronidazole), nitrofurans (furazolidone, nitrofurazone...). 

New clone CC398 of Staph. aureus

(MRSA)
◦ Campylobacter spp –Macrolide and

fluoroquinolone resistance

◦ Salmonella spp - Fluoroquinolone resistance

◦ Enterococci – Vancomycin and macrolide resistance

◦ E. coli - Extended-spectrum β-lactamases (ESBL – e.g. ceftiofur) 

Natural sex steroid hormones:
◦ Oestradiol, progesterone, testosterone

 Synthetic steroid androgens:
◦ Nandrolone, norethandrolone, nortestosterone

 Synthetic non-steroidal oestrogens:
◦ Diethylstilboestrol (DES), zeranol, trenbolone acetate

 Synthetic steroidal progestens:

◦ Melegenstrol acetate (MGA)

 Peptide hormones:

◦ GH and TRH

 β-agonists:
◦ Clenbuterol, cimateratol

 Thyrostatic 

Increase of anabolic effects on proteins and fat depending on the species:

◦ Bovine and ovine increase of muscles,
◦ Pigs and poultry increase on fat deposit.

 Influence on feedback of internal hormones released by the hypophysis (↓), thyroid (↓) and adrenal gland (↑). 

Pronounced secondary sexual characteristics,

◦ Crest development,

◦ Restlessness; animals do not settle in the lairage, mill around,

• Behavioural changes,

• Mounting,

• Aggression,

◦ An even level of finish in a group of cattle of different breed/types. 

presence of implants or pellets,

◦ injection site,

◦ if detected and an oily adjuvant is present, or when the site is in an unusual place, the possibility of the presence of injectable hormones should be considered 

The following signs in a live animal may indicate the illegal use of β-agonist growth promoters:

• Good conformation with little fat,

• Hyperaesthesia and tachycardia may be

present,

◦ Increase of body temperature of 1C,

◦ Muscle tremors,

◦ Dry coughing,

◦ Reduced weight of some organs (liver, heart),

• Flaccidity of the trachea,

• DFD meat. 

Ruminants are more commonly affected than other farm species:

◦ Acute disease with accumulation in liver and kidney, ◦ Chronic disease with accumulation in the bones.

 Can accumulate in the tissue of animals at grazing close to: smelting plants or,

ingesting paints or substances with high lead

content,
◦ Contaminated water supply.

- Can be shed in milk 

- Small wild game contaminated by lead shots 

Acute disease: 

Sudden death

Muscle tremors

Frothing at the mouth

Colic

 Chronic disease:

◦ Dull

◦ Head pressing

◦ Constipation followed by diarrhoea

◦ Apparent blindness

Aggressive behaviour (adults)

Pm finding: can see bone changes 

Animals may be exposed to inorganic or organic arsenic compounds with feed, forage or liquid contaminated with arsenical herbicides, rodenticides or insecticides,

 Chronic disease with accumulation in liver, kidney and bone. Minimal accumulation in muscle usually under the MRL,

 Arsenic poisoning can be seen in swine due to an overdose of organoarsenicals, which are often used as feed additives to promote growth and to control swine dysentery. 

- see haemorrhage disease in kidneys, intestine and body 

Acute Disease: 

- sudden death

- muscle tremors

- frothing at the mouth

colic

head pressing

apparent blindess

Chronic Disease: 

- dull

- colic

- lost of appetite

- apparent blindness

Cases of mercury intoxication are very rare in cattle but pigs can be more affected (contamination of feeding stuff),

 Fishery products more at risk,

 Mercury is very slowly eliminated from the body giving concerns on it’s long- term accumulation in animal tissues. 

Methilmercury is the major source of organic mercury. It works its way up
the food chain through bioaccumulation in the environment, reaching high concentrations among populations of some species. Top predatory fish, such as tuna or swordfish , are usually of greater concern. 

• Species affected: horses, cattle, pigs,

•   Sources: Sewage sludge, organo-cadmium

fungicides, chemical plants

 Vegetables, shellfish and crabs more at risk

 The metal accumulates in body tissue (liver and kidneys) causing kidney deficiency,

 No apparent clinical signs. 

Copper poisoning (acute and chronic) is a common form of farm animal poisoning especially in sheep but also in pigs due to the wide use of metal in agriculture (feedstuff, fungicides, seed dressing, etc.),

 The metal tends to accumulate in liver and kidney and there have been no reported cases of toxicity to humans due to this source,

 Copper deficiency (Swayback). 
- acumm in kidney , liver-becomes dark  

Acute form:

◦ Dullness

 Chronic form (indoor sheep fed concentrates ad lib.):

◦ Abdominal pain

◦ Dull

◦ Salivation

◦ Lethargic

◦ Diarrhoea containing mucus

◦ Tachypnoeic

◦ Faeces dark green in colour 

Chronic form: indoor sheep fed concentrates ad lib

- dull

- lethargic

- tachypnoeic

- anorexic

- pyrexia

- intravascular haemolysis

Acute selenium poisoning may occur in cattle grazing pasture that contains plants which accumulate this element (very rare in UK),

 The most common sign of selenium deficiency (staggers) is flaccid white muscle. 

Organochlorine pesticides (DDT, endrin):
◦ Highly persistent in the environment and accumulation

effect in the food chain.

 Organophosphate pesticides (malathion, coumaphos, dichlorophos)

◦ Sheep dips,
◦ Less persistent in the environment.

•   Carbamates,

•   Dioxins and PCBs (from manufacturing processesof herbicides and fungicides),

 Extremely durable, persistent and bio- accumulating compounds,

Coal fired utilities,
◦ Municipal waste incinerators,
◦ Metal smelting,
◦ Diesel trucks,
◦ Land application of sewage sludge,

◦ Burning treated wood,
◦ Trash burn barrels, 

Italian buffalo mozzarella crisis (2007).

 Irish pork crisis (2008).
 German eggs crisis in (2010). 

an organic base and is used to manufacture melamine-formaldehyde resin, a type of plastic known for its flame retardant properties and commonly employed in countertops, dry erase boards, etc. 

In 2008 six babes were killed and 300,000 were left sickened after consuming infant formula contaminated with the industrial chemical melamine. 

Mycotoxins are a group of naturally occurring chemicals produced by certain moulds.

 They can grow on a variety of different crops and foodstuffs including cereals, nuts, spices, dried fruits, apple juice and coffee, often under warm (25-30oC and humid conditions (85%).

 The mycotoxins of most concern from a food safety perspective include the aflatoxins (B1, B2, G1, G2 and M1), ochratoxin A, patulin and toxins produced by Fusarium moulds, including fumonisins (B1, B2 and B3), trichothecenes (principally nivalenol, deoxynivalenol, T-2 and HT-2 toxin) and zearalenone 

are a type of mycotoxin produced by Aspergillus species of fungi, such as A. flavus and A. parasiticus. There are four different types of mycotoxins produced, which are B1, B2, G1, and G2. Aflatoxin B1, the most toxic, is a potent carcinogen and has been directly correlated to adverse health effects, such as liver cancer, in many animal species.

 Aflatoxins are largely associated with commodities produced in the tropics and subtropics, such as cotton, peanuts, spices, pistachios and maize.

◦ Liver and kidney retain detectable quantities for a longer period,

◦ Dairy products are considered to be the most vulnerable to residue accumulation and transmission of toxic amounts into human food through meat products. 

is a mycotoxin that comes in three secondary metabolite forms, A, B, and C. All are produced by Penicillium and Aspergillus species. Aspergillus ochraceus is found as a contaminant of a wide range of commodities including beverages such as beer and wine. 

is a toxin that was first isolated from Penicillium citrinum, but has been identified in over a dozen species of Penicillium and several species of Aspergillus. Some of these species are used to produce human foodstuffs such as cheese, sake, miso, and soy sauce. 

are compounds produced as a toxic mixture of alkaloids in the sclerotia of species of Claviceps, which are common pathogens of various grass species. The ingestion of ergot sclerotia from infected cereals, commonly in the form of bread produced from contaminated flour. 

is a toxin produced by the P. expansum, Aspergillus, Penicillium, and Paecilomyces fungal species. P. expansum is especially associated with a range of mouldy fruits and vegetables, in particular rotting apples and figs. 

Fusarium  

toxins are produced by over 50 species of Fusarium and have a history of infecting the grain of developing cereals such as wheat and maize. They include a range of mycotoxins, such as: the fumonisins; the trichothecenes; and zearalenone, which is not correlated to any fatal toxic effects in animals or humans. 

• Carcinogenic and mutagenic

•   Haemorrhagic syndrome

•   Pyrexia-pruritis-dermatits syndrome

 Other syndromes (liver and kidney failure, neurological signs)