How to validate the conformity of used fried oils?
I am actually using used oil to coat pet food. I buy this used fried oil from KFC. This oil is used by KFC to fry chicken. Then the latter ( fried oil) is sent to us for use.
We do tests like FFA, Totox, Peroxyde values in this fried oil.
However, I dont have any limits / standards of the above parameters to validate the conformity of fried oils.
Any help please?
Rudra
Dear Rudra,Hello,
I am actually using used oil to coat pet food. I buy this used fried oil from KFC. This oil is used by KFC to fry chicken. Then the latter ( fried oil) is sent to us for use.
We do tests like FFA, Totox, Peroxyde values in this fried oil.
However, I dont have any limits / standards of the above parameters to validate the conformity of fried oils.
Any help please?
Rudra
One quality indicator that some processors use for their (in use) frying oils is ffa value (oleic). Opinions regarding maximum acceptable level vary depending on type of oil, application etc. Some processors set limit at 1%.
eg Palm Oil frying 2005.pdf 223.56KB 126 downloads
However i would hv thought that most pets (and regulations ?) would prefer you to use premium quality oil, ie not previously used.
Rgds / Charles.C
Usually FFA and PV test to decide the oil is still fit for human consumption or not. PV should not exceed 10 Meq/kg. As for TOTOX please refer below:
"Anisidine value (AV) is a measurement of past oxidation. Precisely, it is the measure of aldehyde production during oxidation of fats. AV essentially reflects how an oil has been handled and stored versus peroxide value (PV), which measures current oxidation. For both AV and PV, a lower number is better. TOTOX (total oxidation value) is used to describe total oxidation to which an oil has been exposed. PV x 2 + AV = TOTOX "
Thus, TOTOX do not have limitation.
George
Rancidity is of course the issue.
I agree but in my experience, Colour is often the most immediate issue for oil being used for deep-fried, coated goods. Used oil of ffa 1% can have a significantly different colour to 3% (and similarly the original output
Generally AFAIK there are few explicit international regulatory values for these parameters since they are mostly not interpreted as safety related although oil ffa levels of 6-10% can become somewhat chemically challenged IMO (and smokey).
From Rudra's POV, no idea if pets have any great colour sensitivity. I guess differences may be obscured by the containing matrix although used oil of ffa 1% is IMO likely to have a superior flavour compared to, say, 3%. I have a suspicion smell is often the first doggie rejection factor perhaps followed by estimated cost.
Rgds / Charles
PS (added) @Rudra - You mentioned that you do tests on received oils, what range of ffa / PV levels are you mostly finding ?? Hopefully ffa not all 6% UP ? Is your product stored at ambient temperature ?
Dear Rudra,
One quality indicator that some processors use for their (in use) frying oils is ffa value (oleic). Opinions regarding maximum acceptable level vary depending on type of oil, application etc. Some processors set limit at 1%.
eg Palm Oil frying 2005.pdf 223.56KB 126 downloads
However i would hv thought that most pets (and regulations ?) would prefer you to use premium quality oil, ie not previously used.
Rgds / Charles.C
Dear Charles,
Based on 30+ years experience in the petfood industry, if you want to avoid rancidity issues which can cause feed rejection by the pet and also adverse reaction from the pet owner (due to off odors), the preference is indeed to use oil of a "high" quality.
When I worked for one of the global, market leaders in the petfood industry we once looked at using recycled oil eg from frying operations but we stopped the project due the risks, many of which are unknown and not controllable associated with the use of "old" / used oil.
I would be very surprised if anyone can provide any guidelines, either from within the industry (in which case they are most likely confidential) or legislative, on the acceptability of used frying oil for use in the petfood industry.
However, I throw down the challenge and open up the debate!
DP2006
Dear George,
I agree but in my experience, Colour is often the most immediate issue for oil being used for deep-fried, coated goods. Used oil of ffa 1% can have a significantly different colour to 3% (and similarly the original output). Some oils also change colour more rapidly with ffa than others. One consequence is that customers' specs. tend to minimise the acceptable ffa level (eg1%) while the producer the opposite logic (cost-oil rejection rate)(eg 2-3%).
Generally AFAIK there are few explicit international regulatory values for these parameters since they are mostly not interpreted as safety related although oil ffa levels of 6-10% can become somewhat chemically challenged IMO (and smokey).
From Rudra's POV, no idea if pets have any great colour sensitivity. I guess differences may be obscured by the containing matrix although used oil of ffa 1% is IMO likely to have a superior flavour compared to, say, 3%. I have a suspicion smell is often the first doggie rejection factor perhaps followed by estimated cost.As far as rancidity is concerned, my output was all frozen which probably contributed to the observation that with ffa in 1-3 % range, there seemed little tendency to significant (tasteable) rancidity in a 6 month period.
Rgds / Charles
PS (added) @Rudra - You mentioned that you do tests on received oils, what range of ffa / PV levels are you mostly finding ?? Hopefully ffa not all 6% UP ? Is your product stored at ambient temperature ?
Charles,
Colour is unlikely to be an issue in petfood, unless you are trying to coat a light coloured biscuit / kibble with a dark coloured oil. Whilst the pet might not object from a colour perspective, the marketing people, the petfood retailer and the pet owner might object if something that should be light in colour is darker than expected.
However, the key question is what is causing the darkening of the oil? Could this be due to polymerisation during the heating / frying process that could give rise to the presence of coloured and potentially toxic compounds? Could it be due to the presence of (relatively) innocent colourants from the food that has been fried (assuming the oil has already been used)?
Rancidity is not always an issue in petfood with respect to serious food safety issues eg those requiring vet treatment.
Whilst this seems strange the reason is in the pet's in-built defence mechanisms in that the off-flavours and smells associated with rancidity might mean that the animal rejects the feed.
In doing so it doesn't consume enough to become ill. However, rancidity is still undesirable as it can cause vomiting in the pets and diarrhea and also pet owner rejection. In this context, petfood producers initially look at rancidity in the first instance as an undesirable quality issue ie off odour rather than specifically as a food safety issue.
To address this quality issue extensive control is applied throughout the supply chain from the edible oil producer / supplier through petfood manufacture, shelf-life and into the pet feeding bowl. As indicators of the effectiveness of these controls, parameters like PV, Anisidine Value etc are used, as indicated in other posts on this thread.
Regarding PV please note that this can be miss-leading. For sure a "high" PV means you do have a problem. However, as PV can cycle ie change from low to high to low etc during storage, a low value doesn't tell you a lot! For this reason you need other measures like Anisidine Value.
Regarding the use of "used" oil, please also note that there might also be changes in the nutritional value eg fatty acid composition of "used" oil. Some fatty acids are temperature sensitive and levels can drop during heating.
Hope this helps!
DP2006
In practice, as far as I can see, the wide (unlimited?) scope of the “Used Cooking Oil (UCO)” business seems to have precluded specific recommended product limits for parameters as mentioned in OP. Regulatory data seems similarly absent despite official statements such as –
http://en.wikipedia.org/wiki/Pet_food#cite_note-21In the European Union, pet food is regulated by the same harmonized standards across the EU, via the Feeding Stuffs Act.[21]All ingredients used for pet food have to be fit for human consumption according to EU requirements.
http://web.archive.o...nt Requirements
Very few examples of detailed product specifications for traded UCOs for petfood applications can be found. However most (briefly) advertised products had maximum levels in range 2-6% FFA which sort of correlates to the Quality vs ffa levels shown in 2nd link below –
http://www.ecvv.com/...etable-oil.html
http://www.allqa.com/Oil_Testers.htm
(added) - just to illustrate the possible range of material involved this link illustrates samples of a (hopefully) very low, medium (?) and reasonable quality UCO
http://pacaltenergy.com/uco.html
Two rare examples of commercial UCO specs here (2nd one only limited value) –
petfood used cooking oil spec1.pdf 750.04KB 32 downloads
petfood, Used Cooking Oil spec2.pdf 606.67KB 26 downloads
Peroxide data which probably more directly relates to rancidity is even less advertised. Could not find any UCO specifications. The general comment below is maybe interesting (a limit of 10 as in a previous post of this thread also quoted elsewhere ) –
'..Nutritionists and buyers have arbitrarily established maximum initial PV levels of between 5 and 20 meq O2/kg of fat as acceptable. The origin of these standards is unknown. Carpenter et al. (1966) suggested the source to be from the footnote to a table in a paper published in 1941 (Gray and Robinson). The footnote gave analytical data for a series of meat meal samples and included the comment: “a fat with a peroxide value of more than 20 is definitely rancid”, even though they concluded later in the paper that such “rancid” meat meals may be fed to animals without harm.'
(Does Rancidity, As Measured by Peroxide Value, Affect Animal Performance? C. R. Hamilton, Ph. D. and D. Kirstein, M.S.)
http://www.pet-food-...in_pet_food.htm
Rgds / Charles.C
PS - Rudra, any response to my earlier queries ??
PPS (added)- @DP2006 - thks yr posts, I initially missed yr first one, so far i have appeared to confirm it's predictions.
Dear All,
In practice, as far as I can see, the wide (unlimited?) scope of the “Used Cooking Oil (UCO)” business seems to have precluded specific recommended product limits for parameters as mentioned in OP. Regulatory data seems similarly absent despite official statements such as –
http://en.wikipedia....od#cite_note-21
Very few examples of detailed product specifications for traded UCOs for petfood applications can be found. However most (briefly) advertised products had maximum levels in range 2-6% FFA which sort of correlates to the Quality vs ffa levels shown in 2nd link below –
http://www.ecvv.com/...etable-oil.html
http://www.allqa.com/Oil_Testers.htm
Two rare examples of commercial UCO specs here (2nd one only limited value) –
petfood used cooking oil spec1.pdf 750.04KB 32 downloads
petfood, Used Cooking Oil spec2.pdf 606.67KB 26 downloads
Peroxide data which probably more directly relates to rancidity is even less advertised. Could not find any UCO specifications. The general comment below is maybe interesting (a limit of 10 as in a previous post of this thread also quoted elsewhere ) –
http://www.pet-food-...in_pet_food.htm
Rgds / Charles.C
PS - Rudra, any response to my earlier queries ??
Dear Charles,
Thank you for the additional information you have contributed on the use of used oils and the acceptable limits for Peroxide Values.
I have reviewed a range of animal meal, oils and fats specifications used in the petfood industry, typically the maximum Peroxide Value is specified as 10 mEqO2 / kg. This is in line with the information you have shown. I would take this as an indication of the upper limit of acceptability based on this measurement which as stated before unfortunately does not give the whole picture and could be miss-leading!
For a fresh oil, the specified target PV is typically around 0.1 and the maximum Free Fatty Acid level 1%.
This is very generalized and there is a lot more that any end user like Rudra needs to consider.
Regarding the specifications for used oil sourced from China, there is very little on here regarding the quality of the oil with respect to rancidity eg Peroxide Value, Anisidine Value etc.
One thing that does strike me is the value of 5 (minimum) for Oxidation Stability at 110degC.
Whilst the information given is not extensive, this looks like one of the many measures that can be used to indicate shelf-life eg Rancimat, Active Oxygen Method etc . This value relates to the "Induction Period", the time taken before oxidative rancidity really starts to take off. The higher this value, the more stable the oil and the longer the shelf-life.
As a guideline a relatively stable oil such as refined soyabean oil can be expected to have a value in the range 2 -10. On the basis of the limited information shown ie method not quoted, the indication is that this oil would have a relatively short shelf-life and this includes time in storage and once sprayed onto the petfood. Shelf-life is affected by many factors including temperature, antioxidants used, metal ions etc.
As you can see, the picture around rancidity and oil quality is not a simple one.
Hope this helps!
DP2006
Dear George,
I agree but in my experience, Colour is often the most immediate issue for oil being used for deep-fried, coated goods. Used oil of ffa 1% can have a significantly different colour to 3% (and similarly the original output). Some oils also change colour more rapidly with ffa than others. One consequence is that customers' specs. tend to minimise the acceptable ffa level (eg1%) while the producer the opposite logic (cost-oil rejection rate)(eg 2-3%).
Generally AFAIK there are few explicit international regulatory values for these parameters since they are mostly not interpreted as safety related although oil ffa levels of 6-10% can become somewhat chemically challenged IMO (and smokey).
From Rudra's POV, no idea if pets have any great colour sensitivity. I guess differences may be obscured by the containing matrix although used oil of ffa 1% is IMO likely to have a superior flavour compared to, say, 3%. I have a suspicion smell is often the first doggie rejection factor perhaps followed by estimated cost.As far as rancidity is concerned, my output was all frozen which probably contributed to the observation that with ffa in 1-3 % range, there seemed little tendency to significant (tasteable) rancidity in a 6 month period.
Rgds / Charles
PS (added) @Rudra - You mentioned that you do tests on received oils, what range of ffa / PV levels are you mostly finding ?? Hopefully ffa not all 6% UP ? Is your product stored at ambient temperature ?
Hi,
The FFA levels in used oil is around 10%. Is it safe?
Rudar
Hi,
The FFA levels in used oil is around 10%. Is it safe?
Rudar
Dear Rudra,
IMO the only meaningful comment regarding ffa level is that, as per links in my previous post, it is higher than usually specified in commercially traded UCO products. Safety depends on many factors, eg previous history.
Rgds / Charles.C
Hi,
The FFA levels in used oil is around 10%. Is it safe?
Rudar
Rudra,
Two points I would make about "high" FFA levels eg 10% are:-
- They can accelerate the rate of oxidative rancidity as this can break down fats into glycerides and even fatty acids. In turn this can result in faster rates of rancidity.
- "High" FFA levels can rot your oil storage and handling equipment more quickly than oil with lower levels of FFA.
Hope this helps!
David
Rudra,
Two points I would make about "high" FFA levels eg 10% are:-However, this is not certain and, as with many things, as Charles C states this depends on other factors! There is no easy answer to your questions.
- They can accelerate the rate of oxidative rancidity as this can break down fats into glycerides and even fatty acids. In turn this can result in faster rates of rancidity.
- "High" FFA levels can rot your oil storage and handling equipment more quickly than oil with lower levels of FFA.
Hope this helps!
David
hello,
I wish to have notes on biochemistry of saturated and unsaturated fats. any help?
rudra