Incidental constituents in food

FOOD ADDITIVES

Assessment of the Safety of Food Addit ives

In Malaysia the approval of any food additives under the Food Regulations 1985 is determined by MOH

At the international level, the approval is carried out by Joint Expert Committee on Food Additive (JECFA) FAO/WHO based on the following information or data :

a) Adequate long and short-term toxicology studies, at least on 2 type of animals

b) Adequate information on how the additive is absorb in the body, or its metabolic pathway.

After assessing all these information only the safety level of the additives is determined.

The safety level of an additive is measured by ADI (Acceptable Daily Intake), the amount of the additive that can be ingested each day for life without any risk.

The ADI value is determined with consideration safety factor100 time less than the maximum level that can be eaten by lab animals without any harm.

The ADI value given by JECFA for any chemical is classified base on the assessment carried out as follows:

a. Full or unconditional (FU) ADI : The assessment is complete

b. Temporary ADI (TE) : Given for a period of time only as further information is still needed. However, the toxicology data is sufficient to ensure that the material is safe for the grace period. ADI given can be withdrawn if additional information is not provided within the grace period.

c. ADI not specified (NS) or not limited (NL): Normally the material is presence in food and the toxic level is very low

d. Conditional ADI or Unconditional ADI : Pending re-assessment

e. No ADI allocated (NO): Inadequate information to determined the safety of the material or specification for the identification and originality is insufficient.

Approval for Food Additive  Application  for  the  approval  of  food  additive  requires detailed particulars on the following aspects: 

• Information  on  toxicology  and  pharmacology  tests conducted under the criteria set by WHO

• Proof that the same objective can be obtained by using  GMP

 • The daily intake limit in the diet • The purity standard set by the authorized agencies 

• The benefits to the consumer

• The current status of the additive internationally and  countries that have approved it.

• Type of analysis available to determine the additive level in raw food, during processing and the final products.

• Method to determine the presence of by-product with the  usage 

Risk Factors of Additives As a result of 

- reaction with other chemical/material resulting in risks to consumers

- the weaknesses of the assessment on the safety of the additives

- the purity of the additive itself

FDA – the danger of additives in food is placed 5th. after FP (bacterial), malnutrition, mycotoxin and natural toxin

ANTIBIOTICS&

HORMONES

ANTIBIOTICS 

Chemical substances produced by certain species of microorganisms (bacteria, Fungi, Actinomycetes) that suppress the growth of other microorganisms and may eventually destroy them.

Under Regulation 40, Food Regulations 1985

No one is allowed to import or sell milk, meat or meat products and other foods for human consumption which contain antibiotics or their degraded products

- Chlortetracycline – preservations of poultry

- Oxytetracycline – ice water to preserve fresh fish

- Nisin – cheese and canned food

FOOD Regulations (Amendment) 1998 – around 50 types of antibiotics are allowed.

Use of antibiot ics in animals

- Prevention, treatment and control of diseases

Administration via water, feed and injection

Poultry Diseases (Salmonellosis, fowls cholera, etc)

Swine Diseases (Colibacillosis, Dysentery, enteritis, etc.)

Ruminant Diseases (Diarrhoea, Liver abscesses, Colibacillosis, etc.

Nutritional Use:

As feed additives or water additives, normally at a concentration of 20 ppm in feeds is adequate for promotion of growth.

mainly used for poultry and pig.

Commonly used antibiotics in livestock industry

-        Erythromycin

- Tylosin

- Streptomycin

- Gentamycin

- Neomycin

- Tetracycline

- Oxytetracycline

- Bacitracin

- Oxolinic acid

- Furazolidone BEFORE 1996

Hormones

Classification (chemical points of view):

i.  Glycoproteins  (includes  peptide,  protein,  or  glycoprotein   hormones)

ii. Steroids (includes gonadal and adrenal cortical hormones)

Hormones used in livestock

- In  the US,  the  use  of  hormones  for  growth  promotion and treatment of infertility is regulated.

- In EU countries, the use of hormones is not allowed.

- In Malaysia, the use of hormones for growth promotion is not a common practice.  Normally use for treatment of infertility.

Common hormones use in livestock

 - Somatotrophin (growth promotion)

 - Body growth (bone, muscle, organs)

 - protein synthesis

 - carbohydrate metabolism

 - regulation of renal functions & water metabolism

 - 17B-Oestradiol (treatment of infertility)

 - Progesterone (treatment of infertility))

Impact of uses of antibiotics and hormones

 1. Residues

 - accumulation of parent drug and its metabolites within cells, tissues or organs due to improper use or ignorance of withdrawal periods

- tainting of the aquatic environment and non targeted fish species in water and sediments around aquaculture surrounding.

 - public health concern, potential carcinogenic, allergic or nephrotoxic when consumed over a long time span

E.g.

Allergic - penicillin

Carcinogenic - nitrofurans

Tachycardia - beta agonists

2. Super germ : antibiotic resistant microorganism

As a result of mutation or transfer of resistance (R) plasmids from one bacteria to the other e.g. Sal. Typhimurium and E. Coli are proficient donors of (R) plasmids.

- emergence of cancomycin resistant enterococci (CRE) in human suspected from the use of avoparcin in livestock

  - MRSA (Methicillin Resistant Staph. Aureus)

  - VIRSA/GIRSA (Vancomycin or other glycopeptude intermediately resistant Staph. Aureus)

 3. Abuse of usage

  Beta agonist

E.g. coenobitical, subatomic and ablution

Use in pig farming as growth promoter

(β-Aden receptors cardiac stimulation and lipolysis)

Use in treatment of asthma (β-adenoreceptors smooth muscle relaxation)

Withdrawal period

A withdrawal period for a product is the period of time before slaughter during which antibiotics or hormones must not be given to the animal.  

This  period  allows  for  the  chemical  to  clear  the animal’s  system  by metabolism,  passing  through  the digestive  system or  by  excretion  or  a  combination  of them.

Nitrofuran

 - a group of synthetic chemical produced from nitrofurane

- consist the basic structure 5-nitrofuraldehyde

- 3 used in veterinary medicine

o nitrofurazone

o furazolidone

o furaltadone

-  a stable compound and soluble in water

- used  in  small  dosage  in  chicken  feed  (<100 ppm/metric ton)

-  it  reduces bacterial  infection  in chicken  intestines and acts as a growth enhancer

The toxic effect of Nitrofuran

• No concrete evidence to show that it is safe

• Information on the metabolites of nitrofuran is not known

• Studies conducted in 1988 found that nitrofuran caused cancer in the uterus of rats

• Furalidone is found to increase abortion in rats

• Damage of bacterial cells and caused mutation

Residues in Food

– Due to insufficient information, CODEX or The International Food Standards System do not fix any MRL and ADI

– The EU recommended MRL of 1 – 2 microgram/kg food

– Under the Food Regulations 1985 no residue is permitted.

Uses on human

– as medication for treating wound, burns, ulcers and skin ailments

– however, there are side effects such as headache, dizziness, vomiting and allergic reactions.

The banning of Nitrofuran

– banned in the US, Canada, the EU, and Japan for poultry.

– Australia withdrew the usage in animal feed since Dec 1992.

– Canada banned the usage on animals an no residue is to be found in meat, eggs and milk

– Malaysia, action taken since 1996

PESTICIDES

Pesticides play pivotal role in pest and disease control in food production. FAO estimates 25-40% crop loss to pests, diseases and weeds plus 10-20% to post-harvest losses. Farmers depend on arsenal of pesticides to combat these enemies.

However, the safety of the usage of pesticides will depend on the residues on the crops.

Origin of pesticide residues

A residue will result when a crop or food animal (commodity) or medium of environment (air, water, soils wildlife, etc.) is treated with a chemical, or exposed unintentionally to it by drift, in irrigation water, in feed or by other means.

The chemical will typically be detectable in the commodity at the time of treatment or exposure and also for some period of time afterward.

The magnitude of the residue at any one point in time will depend on the treatment or exposure level and on the rate at which the residue dissipates from the commodity.

1. Volatilization to the atmosphere (influenced by the insecticide's volatility or vapor pressure and the temperature and wind movement in the farm).

2. Washing off by rainfall or overhead irrigation (a function of the chemical's water solubility and the frequency and intensity of waterfall)

3. Chemical degradation (influenced by molecular makeup of the insecticide and by such factors as sunlight, moisture, and temperature).

An insecticide sprayed to protect crops may dissipate by a number of processes, including

5. Metabolism and/or excretion in the case of animals and some plants. The parent chemical may be converted to one or more degradation products that will then constitute the components of the remaining residue.

4. Growth dilution (e.g.. as apples become larger, the chemical residue concentration will decrease even without physical or chemical dissipation or residue from the fruit).

Residues in vegetables (Malaysia.)

1. Methamidophos contaminated kai lan (>MRL 1mg/kg in Dec.1988),100 people affected in S'pore

2. 2,4-D in bean sprouts (taugeh) for root restriction found in most major towns

3. Rice-contamination more during storage /post harvest treatment however persistent pesticides, lindane found in grain.

Washing prior to cooking destroy 80% of residue.

Legislation for the control of Pesticides in Malaysia are :

1. The Pesticides Act 1974 - The Pesticide Board

2. The Food Regulations 1985 (Amended 1995)

3. The Environment Quality Act 1974

4. The Occupational Safety and Health Act 1994

5. The Hydrogen Cyanide Fumigation Act 1953

The End