Emu Oil Document: International Emu Oil Standards
International Emu Oil Standards: Introduction
These Standards are for finished and crude oils. "Finished" oil is defined as oil which has been "refined, bleached and deodorized" by processes generally recognized in the commercial oil industry. All other oils are defined as "crude." The Standards are consistent with results from qualified independent laboratories, members' and non-members' collective experience and judgment, as well as previous work done in Australia.These Standards were developed by the AEA Oil Standards Team under its mission to "establish industry guidelines and standards to help assure the profitable growth of safe global ratite oils markets." Team members bring broad and relevant experience representing the entire value-adding chain from raising birds to research to sales and marketing. Two members are from Canada, four from Australia, and fourteen from the US. There are two Medical Doctors, a Doctor of Pharmacy, two university professors, and several engineers on the team. And we draw support from a worldwide network of other resources, including the American Oil Chemists Society (AOCS), the international organization for "those with a professional interest in the science and technology of fats, oils, and related substances."
Most of the analytical methods specified are AOCS methods that are standard for the oil industry worldwide. Many of the classical measures that are applied to oils lack specificity such that numerical values will overlap oils from other sources. Taken collectively, however, a fingerprint may emerge that is reasonably unique for emu oil.
Measurements of anti-inflammatory and other forms of activity have yet to be incorporated into the Standards. Activity evaluation is currently under way as an ongoing part of the Team's work - with the full recognition that specifying activity is a far more complex (hence, expensive and lengthy) task than the oil measures contained in the current Standards.
Please note the distinction between "guidelines" and "standards" used in this document:
- Guidelines are those specifications that are based on broad experience in the industry, and, in some cases, data. Guidelines should be followed as if they were standards unless your specific data and experience clearly show a guideline to be inappropriate or unnecessary for your oil.
- Standards are those specifications for which support data are statistically significant or the specification is clearly justified by industry experience. Standards should be met except where a customer expressly requires a different specification. Further, suppliers are encouraged to develop premium and/or specialty oils within the Standards.
The Guidelines cover pre-oil quality and safety considerations.
The Standards are in two sections; a background discussion of all the Standards and the specifications.
I. BIRD CONDITIONS
Birds intended for processing into meat and/or oil should be disease-free, healthy birds. They should be raised in an environment which guarantees that products derived from the carcass comply with international standards for freedom from contamination with antibiotics, pesticides, herbicides, heavy metals, worming medicines, growth stimulants, hormones and/or like substances.
II. BIRD PROCESSING CONDITIONS
Birds should be humanely slaughtered in such a way that they are effectively stunned when they are bled. Electroshock and CO2 hoods have been used effectively to accomplish humane slaughter.
III. FAT COLLECTION AND STORAGE
Fat should contain a minimum of blood, meat, bone and feathers. Fat should be refrigerated as soon as possible but in any event, within a maximum of two (2) hours after removal from the carcass. If the fat is to be processed more than six (6) hours after removal from the carcass, it should be frozen as soon as possible. Fat to be kept longer than ten (10) days should be stored at -20° F. It is desirable to minimize the thickness of individual packets of fat to assure that the fat is quickly and completely frozen. [Fat in five (5) to fifteen (15) pound sealed plastic bags with one dimension no more than three (3) inches tends to freeze well. Packets should be completely frozen before packing into a larger container.]
IV. EQUIPMENT FOR FAT HANDLING AND OIL PROCESSING
Governmental guidelines for food-grade equipment should be the primary reference for materials of construction and other relevant details. In Australia, consider Australian Quarantine and Inspection Service's "International Code for Storage and Transport of Oils and Fats in Bulk," CAC-RCP 36-1987. In the US, consider USDA's guidelines for sanitary design and fabrication, FSIS Directive 11220.1. In other countries, equivalent codes/standards should be followed. Specifically, materials of construction must be limited to non-reactive materials, e.g., glass, epoxy, etc. Where metals are your choice, ONLY 300 series stainless steels should be used unless your specific experience and analysis show a different metal to be fully acceptable.
Adulteration by adding oils from other sources is a potential problem for any valuable oil. Therefore, work will continue on the detection of non-emu oils at very low levels. In any event, it is a basic requirement that the oil has been derived from only emu fat and has not been blended with any other oil.
II. MICROBIOLOGICAL LEVELS
No amount of attention to hygienic conditions can prevent the contamination of the external surface of emu fat. The consequence of the contamination depends on many factors. These factors include, but are not limited to, the following:
- the specific contaminating organism,
- the quantity of organisms present in the oil, and
- how the oil is used.
The fat is best chilled as quickly as is feasible (see Guideline III, "Fat Collection and Storage"). Rapid chilling minimizes enzyme activity that can quickly degrade the fat. And it also minimizes the growth of contaminating organisms.
Microbial growth is aided by the presence of water, nitrogenous nutrients and warm temperatures. Therefore, the choice of processing conditions should be made with this in mind. As the rendering process progresses, water and contaminates tend to be removed from the crude oil. However, unless specific steps are taken to remove the microbial contaminates from the oil, they must be assumed to be present. (Some may choose to hold the oil at 300° F in the absence of oxygen and other reactive materials for one hour to sterilize it. Other methods may also achieve similar results.) Detection of this contamination is made difficult by the very high fat content since most culture media used to grow organisms are water based. Therefore, low level test results for microbial contaminates must be accompanied by process procedures that can assure removal of such contaminates.
While the Standards specify a very low level of microbial contaminates, it is reasonable that some purchasers of emu oil will assume this responsibility. Subsequent formulation manipulations of the oil may present additional opportunities to contaminate the oil. Most of these manipulations will not be done in sterile conditions and this risk also should be managed.
III. WATER (AND OTHER CONTAMINATES)
Generally speaking, conditions that are associated with deterioration of emu oil are water, temperature, oxygen, enzymes, and impurities such as blood and other odor-causing proteins. The presence of any of these materials will accelerate the deterioration processes. But iron oxide (rust) and zinc (from galvanized coatings) are triggers of deterioration as well. Ultra-violet light can also degrade the oil. Even short exposure of the oil to brass or copper can cause the oil to become odorous. All other things being equal, stability increases as water content decreases. Low water content also minimizes growth of bacteria, yeast, fungus, and mold. Most of these elements are controlled by oil processing conditions. Properly finished oils may be essentially without water through the appropriate combination of temperature, vacuum, agitation, and time.
As with any oil, fatty acids that are the most unsaturated are at the greatest risk of early degradation as water content increases. Usually these fatty acids are also the essential fatty acids, linoleic acid and linolenic acid. (Essential fatty acids are, by definition, those fatty acids that we must obtain from our diet since the body cannot manufacture them.)
IV. APPEARANCE (pending)
Oil generally is white to a light straw color depending on age and feed of the bird. Some oils may have an even darker color.
V. ODOR (specifics pending)
Any objectionable odor has significant negative potential. Pure oil has no objectionable odor, so these problems are the result of contamination of some sort. Proteins with water are the most likely sources. Therefore, efforts to generate oil free of any contamination are crucial.
All animal and vegetable fats/oils are subject to natural degradation processes that can be accelerated by exposure to heat, light and oxygen. The presence of normally occurring substances such as protein and trace metals may also accelerate this degradation. In addition, animal fats naturally contain enzymes whose purpose is to aid in the movement of the fat back into the body's circulation when called upon by energy demands. All of these factors contribute to the cleaving of the fatty acids from the triglycerides. Appropriate refrigeration can substantially reduce the negative effect of all these conditions. Free fatty acids less than 3% are not a stability issue in oil where water and oxygen are at very low levels.
VII. PHYSIO-CHEMICAL CHARACTERIZATION
Several tests are used for this characterization: specific gravity, viscosity, refractive index, iodine value and saponification value. The iodine value measures the quantity of iodine that can be chemically added at the points of unsaturation of the fatty acids. The saponification value measures the quantity of potassium hydroxide that is required to cleave all the fatty acids from the triglycerides. All such measures have a certain degree of uniqueness for individual oils. As with many tests of this nature, there is a lack of specificity such that many oils will have similar or overlapping values. However, deviations outside the ranges provided suggest that the oil may have been adulterated in some manner.
VIII. MAJOR FATTY ACIDS AND IX. MAJOR TRIGLYCERIDES
Fats are a heterogeneous group of compounds that are characterized by their solubility in solvents such as ether and, therefore, they are insoluble in water. Emu oil is rendered primarily from the fat pads of the bird or from what is referred to as the "storage lipids." Emu fat is "storage" fat, as in most animals and organisms, which means it is the principal form of stored energy. As an energy source, it is completely combustible to carbon dioxide and water. This releases a quantity of energy similar to the combustion of a fossil fuel.
This storage fat is fairly simple in its composition. It contains a very small amount of water and cholesterol. (See sections II, III, and X for the importance of the water and sterol contents.) It is essentially 100% triglycerides in composition. A triglyceride is comprised of a glycerin backbone to which three fatty acids are attached. The specific mix of fatty acids is likely to be specie specific. Therefore, the mix of fatty acids is useful information. (Feed and other factors also influence fatty acid mix.) Additionally, the order of attachment of the three fatty acids to the glycerol molecule to form the triglyceride also is likely to be specie specific.
Many of the reported benefits from the applications of emu oil can be broadly classified as involvement in:
- cell structure and function and
- hormonal control.
A discussion of the involvement of fatty acids in the body's chemistry and physiology is beyond the scope of this commentary. Some of the fatty acids play crucial roles as enzyme cofactors, electron carriers, light-absorbing pigments, hydrophobic anchors, emulsifying agents, hormones, and intracellular messengers. Any number of these vital activities, along with the cell structure and functions, may help explain the benefits attributed to the uses of the oil. The AEA Oil Standards Team is seeking a basic understanding of how emu oil contributes to these actions.
X. STEROLS - UNSAPONIFIABLE FRACTION (STEROLS AS A MEASURE OF PURITY)
The sterol fraction is often the larger portion of the unsaponifiable fraction of either animal or vegetable fats. Saponification refers to the chemical reaction that results in the formation of fatty acid soaps. When sodium hydroxide or potassium hydroxide reacts upon fats such as triglycerides, the fatty acid components of the triglycerides are converted to their sodium or potassium salts that are "old time" soaps. The fats, which are not reactive with sodium or potassium hydroxide, are referred to as the unsaponifiable fats. The major portion of the unsaponifiable fraction is the sterols. These are cholesterol and cholesterol-like substances which have a characteristic chemical composition that may simply be described a "closed ring" in contrast to the "chain" or "open ring" appearance of the triglycerides and fatty acids. The cholesterol molecule is the classical "steroid" molecule. This molecule is common to a number of chemicals important to humans; e.g., the anti-inflammatory steroidal hormones such as hydrocortisone, the androgens such as testosterone, the progestogens, the bile acids, vitamin D, and estrogen.
As demonstrated in Tables 1 and 2, the plant sterols are different from the animal sterols. Plants produce mostly sitosterol and very little, if any, cholesterol, with the possible exception of corn oil. (See Table 1.) Therefore, a high level of sitosterol in an oil suggests that at least some of the oil is a vegetable oil. Even though some sitosterol may be ingested by the birds from plant sources or feeds, pure emu oil should have minimal (<50 ppm) sitosterol.Table 1, Unsaponifiables in Vegetable Oils*
|Oil||Total Unsap. (%)||Sterol fraction (%)||Sterols fractionated|
|Sitosterol (%)||Stigmasterol (%)||Compesterol (%)||Cholesterol (%)|
NOTE: IN THIS TABLE, a sterol fractionation can be seen as parts per million (ppm) by multiplying its percent by its percent of sterol fraction and then multiplying by 1,000,000; e.g., cottonseed sitosterol at 89% multiplied by cottonseed sterol fraction at 0.4% multiplied by 1,000,000 (0.89 x 0.004 x 1,000,000) = 3560 ppm.Table 2, Animal Fat Analysis*
** American Emu Association's AEA News, Vol. 5, No. 7 - Fall 1996 (There are reports of some emus showing linolenic acid, C18:3, values as high as 18%.)
The oil has only been derived from emu fat and has not been blended with any other oil.
II. MICROBIOLOGICAL LEVELS for crude and finished oils intended for food and/or pharmaceutical end uses.
|Aerobic microbial count||< 10||AOAC|
|Combined yeasts and molds||< 10||AOAC|
** III. WATER
|< 0.5%||< 0.05%||AOCS, Ca 2c-25|
* All other things being equal, stability increases as water content decreases.
IV. APPEARANCE (See comments under Standards - Background, IV.)
V. ODOR - No objectionable odor. (specifics pending)
** VI. STABILITY
|Free fatty acids||< 1.5%||< 1.5%||AOCS, Ca 5a-40|
|Peroxide value||< 25||< 10||AOCS, Cd 8b-90|
VII. PHYSIO-CHEMICAL CHARACTERIZATION (crude and finished oils)
|Specific gravity @ 40° C||0.897 - 0.920||AOCS, Cc 10a-25|
|Viscosity @ 40° C||31 - 43||AOCS, Ja 11-87|
|** Refractive index @ 40° C||1.456 - 1.467||AOCS, Cc 7-25|
|Saponification value||190 - 200||AOCS, Cd 3-25|
|Iodine value||65 - 75||AOCS, Cd 1-25|
VIII. MAJOR FATTY ACIDS (METHOD: AOCS, Ce 1c-89) (crude and finished oils)
|Identity||Name||Mean (%)/1 SD||Range (° 3 SD)|
|C14:0||Myristic||0.4/0.08||0.17 - 0.68|
|C16:0||Palmitic||22.0/1.50||17.5 - 26.5|
|C16:1||Palmitoleic||3.5/0.78||1.2 - 5.7|
|C18:0||Stearic||9.6/0.80||7.2 - 12.0|
|C18:1||Oleic||47.4/3.00||38.4 - 56.4|
|C18:2||Linoleic||15.2/3.00||6.2 - 24.2|
|C18:3||Linolenic||0.9/0.30||0.1 - 1.8|
* Any trans-fatty acids present may be related to feed and/or processing.
IX. MAJOR TRIGLYCERIDES (METHOD: HPLC, AOCS Ce 5b-89) (crude and finished oils)
|Identity||Name||Mean (%)/1 SD||Range (° 3 SD)|
|ECN 42||LLL, OLLn, PLLn||1.0/0.5||0.1 - 2.5|
|ECN 44||OLL, PLL||10.0/2.0||4.0 - 16.0|
|ECN 46||OOL, POL, SLL||28.2/4.2||15.6 - 40.8|
|ECN 48||OOO, POO, PPO, SOL||48.2/5.0||33.2 - 63.2|
|ECN 50||POS||5.8/0.8||3.4 - 8.2|
P = palmitic, S = stearic, O = oleic, L = linoleic, Ln = linolenic
X. STEROLS - UNSAPONIFIABLE FRACTION (METHOD: GC/MS) (crude and finished oils)
|Sitosterol||< 50 ppm|
** Suggested routine tests