Observation of beef fat moisturizing cream - Identification of elements

[N3ptune]

Hi,

I've got a friend at the job, she has passion for many things and she is making her own moisturizing cream out of beef fat, processed in a certain way. Can't remember the procedure right or the other ingredients now but the cream is pretty awesome so far and it looks like cream.

I decided to look at 1 sample to see if it could contain moving bacteria and nothing moves in it my guess is no bacterial infestation, at least not in the only sample I took.

***
Many interesting things can be observed.

These are my pictures starting at 100x , then 1 picture at 250x, a couple of pictures at 400x and the last pictures at 1000x (200 μm FOV)
https://drive.google.com/file/d/189ST2f ... share_link

Does anyone have an idea of what these 2 things bellow can be, and if anything else can be identified easily?

A. This little bladder with some kind of coil ring, what could that be?


B. There are elements of various colors inside of that bubble, I think that we are NOT looking inside of the same thing as picture A, it's not the same thing. But there are red dots, and green dots, beige dots, bluish dots. These would be around +-1.5 μm. What could these colored dot be?


Thanks

[N3ptune]

Oh this message would have been better positioned in Identification help.

Sorry about that.

[Dennis]

I am just picturing someone sitting there having beef moisturizing cream on and the flies flying all around them.

My Aunt, like me, went through severe eczema problems. She had Crisco shortening rubbed all over herself and plastic sheets on the bed.

I don't know how that would not be a breeding ground for bacteria !
I would think maybe all those dots are bacteria.

[patta]

I'd say that the large vacuoles are just air bubbles; the small grains are the fat granules. It seems that the fat granules assemble at the surface of the bubble, due to surface tension/van der waals; or the thick border is just an optical effect from defocus/refraction/phase.
The granules inside the bubbles, may be actually the fat particles in the water base out of focus?
Why you didn't use a coverglass?

[ldflan]

If you really want to find out whether the beef fat moisturizer is contaminated with bacteria, and / or with what, you're going to have to do a good deal more work, I think.

My first thought was culturing a sample of the cream on a sterile agar plate with nutrients made from beef fat. This would not actually be difficult if you own or have access to a pressure cooker. I took a quick peek at the literature, and it looks like comparative studies of both type and degree of fat contamination have been done by comparing the colonies that grow from a standardized animal fat sample in just that way. I am not really sure how valid that method is for quantitative analysis, but it's something. Anyway, once you grow out pure cultures you could analyze them in a variety of ways that could certainly include staining and your microscope. There are some hazards associated with growing cultures of this sort, but they are probably not much worse than you encounter cleaning out your fridge.

I do think it is probably next to impossible to directly stain any bacteria while they are suspended in an oily mass of fat. Maybe some kind of homogenization procedure would do it? But short of such staining, I doubt you will easily be able to identify any bacteria in situ while suspended in the cream, which is probably made up of microscopic lipid droplets. I ran a Google search and found that the FDA has a recommended procedure for what you are trying to do in the case of foods:

Direct Microscopic Examination of Foods (Except Eggs)

Equipment and materials
Glass slides, 25 × 75 mm, with etched portion for labeling; 1 slide for each blended food sample (10-1 dilution)
Wire loop, 3-4 mm, platinum-iridium or nichrome, B&S gauge No. 24 or 26
Gram stain reagents (R32)
Microscope, with oil immersion objective lens (95-100×) and 10× ocular
Immersion oil
Methanol
Xylene
Procedure
Prepare film of blended food sample (10-1 dilution). Air-dry films and fix with moderate heat by passing films rapidly over Bunsen or Fisher burner flame 3 or 4 times. Alternatively, air-dry films and fix with methanol 1-2 min, drain excess methanol, and flame or air-dry (this is particularly helpful for foods with a high sugar content). Cool to room temperature before staining. De-fat films of food with high fat content by immersing films in xylene 1-2 min; then drain, wash in methanol, drain, and dry. Stain film by Gram-staining procedure (R32). Use microscope equipped with oil immersion objective (95-100×) and 10× ocular; adjust lighting systems to Koehlor illumination. Examine at least 10 fields of each film, noting predominant types of organisms, especially clostridial forms, Gram-positive cocci, and Gram-negative bacilli.

[You could probably substitute other de-greasing agents for the xylene if xylene is not an option. Maybe what we call napthalene in the US (e.g., Rosignol lighter fluid)?]

As for the "bladders" or whatever they are, honestly I think it's pretty hopeless to ask for an identification when we don't even know what was put in the cream to begin with, beyond beef fat.

The fact is that with just a few exceptions like pond water, effective microscopy is more about sample preparation than it is about using the scope itself...

I'll be interested in any progress on this. I doubt your friend wants to know what's in there...

[N3ptune]

@dennis good questions about the breeding ground for bacteria, it is apparently a real recipe for cream and there is a full procedure for processing the fat which takes multiple hours apparently, this probably makes the fat less a breeding ground but I don't know more then that.

@idflan thanks for the whole procedure.. it's a lot of work like you say. If I don't do it soon at least I learned one way to study bacteria growing on fat and not by just looking at the cream like that..

[ldflan]

The FDA procedure I cut and pasted above really isn't so difficult, and fairly typical for smear processing - except for the de-greasing step. I think the process (once you figured out how to do it right) would take maybe an hour, most of that time spent waiting for things to dry, stain, or cool. The materials and equipment are all things you probably will want to have on hand for microscopy anyway. You'd need to buy a Gram staining kit (or make it up yourself), a bottle of methanol, and a bottle of xylene or other degreaser (both from the local hardware store would be fine). You'd need a slide, an appropriate mounting medium (Permount or whatever), a cover slip (all of which you should have). You'd want a clean flame source (a cheap alcohol lamp would work fine, and again this is something you will want for flaming slides) - a butane lighter (one of the kind for lighting fires with the long tube) would do in a pinch. Finally you'd need some eyedroppers and and a few staining dishes or jars (old jam jars, say, again things you want to have on hand). The materials are highly volatile and combustible, of course. If you're using xylene, it's an outdoor (or fume hood) activity for sure.