Purrs In Our Hearts - Cat Forum UK

Cat Health & Behaviour => Health & Behaviour General => Topic started by: Mark on May 03, 2007, 15:59:46 PM

Title: Phosphorus levels in cat food (Whiskas & Sheba)
Post by: Mark on May 03, 2007, 15:59:46 PM
I have just spoken to Masterfoods to get some phosphorus levels as Clapton is eating Sheba at the moment.

If anyone is interested

Sheba Terrines = 0.2 grams per 100grams
Whiskas in Jelly 0.42 grams per 100 grams
Whiskas supermeat 0.29 grams per 100 grams
Whiskas senior 0.20 grams per 100 grams

The figures sound quite low - I will have to look on Tanya's site to compare.
Title: Re: Phosphorus levels in cat food (Whiskas & Sheba)
Post by: Millys Mum on May 03, 2007, 16:43:16 PM
Thanks for posting that Mark  ;D
Title: Re: Phosphorus levels in cat food (Whiskas & Sheba)
Post by: CurlyCatz on May 03, 2007, 16:55:57 PM
do you have the "ideal range" amounts mark ? for future reference.
Title: Re: Phosphorus levels in cat food (Whiskas & Sheba)
Post by: Tiggy's Mum on May 03, 2007, 17:38:50 PM
Lynn, The ideal range is below 1% phosphorous, prescription foods tend to be 0.5% or less.  The highest on the list is Hi-life seafood at 6.8%  :Crazy:  http://www.felinecrf.org/tinned_food.htm

Is that dry matter analysis Mark?  Just to confuse things below is from the CRF website:

Cat foods vary in how much moisture they contain, which makes it difficult to compare them to each other. It is very hard, for example, to compare a tinned cat food to a dry cat food because the former naturally contains much more water; and this affects all the percentages of the different nutrients. Dry matter analysis is a way of comparing foods assuming all the moisture content has been removed: this makes it easier to compare different products. Whenever this site mentions levels of the various components of foods, it is talking about them on the basis of dry matter analysis, which is not necessarily the same as what it says on the tin.

Let's take an example. Let's say:

you give your cat a food with 80% moisture, a typical level for many tinned foods;

the food apparently has phosphorus of 0.25%;

your cat eats 100g of the food.

It therefore appears that your cat is eating 0.25g of phosphorus (100g x 0.25%).

However, the food is 80% water. So of the 100g your cat has just eaten, 80g (80%) of it was simply water, and only 20% was actual food, or dry matter. So the amount of phosphorus is actually higher - in percentage terms - than it first appeared, i.e. your cat has eaten 0.25% divided by (100%-80%) or 1.25% phosphorus.

Another way of looking at it is to say that your cat food initially had 1.25% phosphorus. Then the manufacturers added 80% water. There is still the same total amount of phosphorus in the food, but at first the percentage appears lower because of the diluting effect of the water. So in order to understand exactly how much phosphorus your cat is eating, you need to discount the water in the food.
Title: Re: Phosphorus levels in cat food (Whiskas & Sheba)
Post by: Mark on May 03, 2007, 17:41:13 PM
No, I'm confused by that  :Crazy:

I think the figures she gave were % per 100 grams of wet product which didn't seem to make sense. I suppose unless you know the moisture content, it's impossible to work out the dry matter %  :Crazy: :Crazy:
Title: Re: Phosphorus levels in cat food (Whiskas & Sheba)
Post by: Tiggy's Mum on May 03, 2007, 17:44:16 PM
Yeah exactly, the bit from the CRF website below explains that much better than I could have attempted!  To work out the phos content you really need to know the dry matter figure.  Were they very helpful?  Maybe you could give them a ring and see if they will tell you the dry figure.
Title: Re: Phosphorus levels in cat food (Whiskas & Sheba)
Post by: Tiggy's Mum on May 03, 2007, 18:05:21 PM
I just opened a pack of kitten treats for the boys and noticed it had the moisture % on the back.  Looked at the back of Natures Menu and that had the moisture content listed too so it may well be on the packet or tray itself.
Title: Re: Phosphorus levels in cat food (Whiskas & Sheba)
Post by: Mark on May 03, 2007, 18:07:23 PM
I will try again tomorrow. I'm sure they won't have those figures to hand. I thought it was too good to be true that Whiskas brands were low phosphorus  >:(

Anyway, he's eating sheba with a fortekor surprise right now  :evillaugh:
Title: Re: Phosphorus levels in cat food (Whiskas & Sheba)
Post by: Tiggy's Mum on May 03, 2007, 18:12:45 PM
Have you seen my latest post, it might be on the back of the tray or pouch...  Is Sheba made by Whiskas then?  Think yourself honoured if it is, Whiskas wouldn't release any info to the other Helen, author of the CRF website - that's why they don't feature on her list of foods that she has compiled!
Title: Re: Phosphorus levels in cat food (Whiskas & Sheba)
Post by: Mark on May 03, 2007, 18:21:13 PM
I guess it like most companies, it depends on the person you speak to a lot of the time. She had a sheet she was reading off. If she is a cat-lover, I suppose it helped that I said my cat was sick but refusing prescription food. I said he was happy eating sheba but I wanted to make sure it wasn't going to make him any sicker. Unless they have changed their policy?

Sheba is made by masterfoods (Mars confectionery) as is Whiskas.

I just looked on the back of the tray and it says moisture 81% (sorry helen I missed that on your last post)

Any maths boffins who can work out the dry-matter From that?

Are you in touch with Helen, Helen?  ;D She might be interested in those figures given that Whiskas is the no1 catfood
Title: Re: Phosphorus levels in cat food (Whiskas & Sheba)
Post by: Mark on May 03, 2007, 18:28:27 PM
I just looked at the CRF site again and give or take, if the moisture content is 80%, you x the % x 5 to get the dry matter % (I think)

Making the Sheba terrines around 1% which isn't great but not too bad at all - same goes for the senior.
Title: Re: Phosphorus levels in cat food (Whiskas & Sheba)
Post by: Tiggy's Mum on May 03, 2007, 18:35:58 PM
1% is pretty good for a standard non prescription cat food, especially if Clapton likes it aswell!  I will email Helen and let her know that Whiskas may well be releasing data now, I know she tried unsuccessfully in the past. 
Title: Re: Phosphorus levels in cat food (Whiskas & Sheba)
Post by: CurlyCatz on May 03, 2007, 21:00:29 PM
i never can work out the differences when you get figures of ie 0.2g/100g and then what that is in percentages  :Crazy: :Crazy:

I was terrible at maths even though i did manage all my pharmacology / drug calulation/ ivft requirements etc but i DID have to make sure i wasnt hungover or still drunk during those lectures  :evillaugh:
Title: Re: Phosphorus levels in cat food (Whiskas & Sheba)
Post by: Mark on May 03, 2007, 22:23:42 PM
Although I put grams, I think she said 0.2 % per 100 grams (isn't that the same?)
Title: Re: Phosphorus levels in cat food (Whiskas & Sheba)
Post by: Susanne (urbantigers) on May 03, 2007, 23:46:24 PM
This is a good site for explaining how to calculate dry matter analysis.

http://www.thepetcenter.com/imtop/dm.html

I calculated quite a few for their phosphorus levels a while back (incuding applaws and natures menu) on a dry matter basis.

I can work out the dry matter figures some other time if you have phosphorus in 100g and % moisture (varies from about 75% to about 82% in wet foods) - tonight my brain is frazzled after election stuff.  In fact I don't even have the brain power to read this thread properly right now and am only up because Jaffa is on my lap wanting cuddles.

The % phosphorus in natures menu calculated on a dry matter basis is approx 1.5% and most of the applaws (all the ones I've calculated) are about 0.7%
Title: Re: Phosphorus levels in cat food (Whiskas & Sheba)
Post by: swampmaxmum on May 04, 2007, 11:12:21 AM
So when the websites say % 'as fed', does that mean that they've discounted the water from the can? Very confusing and imposs for this maths dunce. Is there any kind of EU quality control on whether it's actually true anyhow? (somewhat lost faith in the food cos).

Title: Re: Phosphorus levels in cat food (Whiskas & Sheba)
Post by: Susanne (urbantigers) on May 04, 2007, 11:32:33 AM
As fed means including the water.

Things like this are calculated on a dry matter basis so that you can compare foods, as they all contain slightly different amounts of water (and of course dry food considerably less water than wet).

It's fairly simple to calculate so long as you know the percentage phosphorus (if you only have the amount phosphorus in a serving you may need to calculate that if the serving size isn't 100g) and the percentage water.  You need to work out the reciprical of the water percentage, which is just 100 - the percentage water.  So if a food is 80% water the reciprical is 20%.  Then you just divide the percentage phosphorus (as fed) by the reciprical.

eg if a food has 0.5% phosphorus and 80% water, the calculation would be 0.5/20 = 0.025.  Then multiply by 100 to get the figure as a percentage (or just use % button on calculator and omit this step!) = 2.5%.

So the food that initially seemed to be 0.5% phosphorus is actually 2.5% phosphorus when you look at it as dry matter, and that's the figure that's relevant to anyone with a CRF kitty who's looking at phosphorus levels and wanting to choose foods towards the lower end of the scale.