For example how could you identify toxins in the simplest manner? I've got a few ideas such as microscopes and spectrometers. A microscope could be used to look at the morphological structure of what is growing in the batch, and if it looks like yeast it's more likely to be yeast, but short of sequencing the dna, how can you make sure there isn't some yeast impostor that looks and behaves similar to yeast but is actually producing some toxins? So I thought one could use spectrometers to measure the chemicals in the batch, and on the face of it I am thinking this is simpler than both dna sequencing and microscopic analysis. Even simpler one could measure the gravity of the solution and if you put sugar in and something is eating it up producing characteristic smells and moving the gravity towards that of water, it is more likely to be yeast. But I've read horror stories of people becoming paralyzed and even stopping breathing because botulinum toxin for example can be made along side the ethanol by bacteria who don't mind the yeast. So how do I not kill myself with out spending a fortune on equipment?
Wow! Its seems a lost knowledge that brewing was used to purify water - not make it unsafe to drink. There is absolutely no need for the average home brewer to set up a brew lab just to make "safe" beer or wine. Home brewing just does not have that requirement.
The basic premise of fermentation is that if the system is anaerobic but acidic then it is generally OK. Beer wort is about pH 5 or lower. Brewed beer is about pH 3.5. Alcohol also acts as a antimicrobial. If the system is aerobic and acidic then it is usually OK - although it may smell strange! Vinegar is made in such a way. If the system is anaerobic and not acidic then the alarm bells should start ringing. Botulinum toxic is only produced in anaerobic and non-acidic conditions. In the US one of the main causes of Botulinum toxin in home made produce is preserving raw vegetables in oil - garlic is a good example.
Using clean (as it well washed and rinsed, then boiling water scalded immediately before use) equipment, tap water, malt, hops and yeast, one can brew beer very well - and safely. Using foot pressed grapes and clean equipment one can produce very reasonable wine without a campden tablet in sight. Home brewing to my knowledge has never harmed anyone, except when they get too drunk and suffer an accident. So unless the circumstances are quite unique, there really is no need to worry about poisoning.
if one really wanted to set up a brew lab then one might read a suitable book (eg "Yeast" by C.White and J.Zainasheff) which at least gives a background to the process and details many procedures. A microscope (with micrometer platform) and some dyes for yeast viability testing might be a start. UV/IR spectroscopy is not all that useful unless one has a digital peak reference database. Chromatography is a better bet - both gas and liquid column work well enough to isolate and characterise compounds. But the full identification would need something like a Mass spec with elemental analysis - which might be expensive unless one has access to a analytical lab.
Well, for starters, if it was so easy to grow toxic organisms alongside yeast, then humanity would probably already been wiped out.
Microscopes are used in brewing, but mostly only for counting yeast cells.
And about using a mass spectroscope to test your batch, I hope you do realize that this kind of equipment is at most 150 years old, and that humanity has been brewing at least 6000 years?
So, think about this: if humans without technology were able to brew without poisoning everybody, without the presence of advanced lab equipment, why should you?
Being a good brewer is actually about "handling with care", and handling with care is cleaning your equipment and sanitizing it at the right moment, and try to make sure that you try to have the least possible oxygen ingress (not for harmful organisms, but against oxidation). The only lab materials you really need are a thermometer and a hydrometer.
The difference between "handling with care" and lab equipment is, when you handle with care, you will prevent contamination. With lab equipment, you could possibly detect contamination (but you will probably do that with sight, smell and (possibly) taste too), but then it is already too late. Your precious work is spoiled, and no amount of lab equipment will help you to save it.