I'd like some suggestions on how to improve one's usefulness in the lab without actually working in the lab.
This might not be possible, but I would love to be wrong.
Experience in the (chemistry) lab is about using your hands to perform specific and often complex tasks with dexterity and proficiency. Many of these tasks also have associated hazards, which through experience can be avoided or minimized.
I am afraid that if you are interested in pursuing a career in chemistry or another lab science, you will need to get some experience in the lab. The easiest way would be take a few courses. Given your interests, you should at minimum take and organic lab course and a microbiology lab course.
Let's take as an example a simple distillation, a common organic lab technique. No amount of reading about the technique prepares you for the many things that could go wrong. At least one of these has potentially disastrous consequences. If you take a course where you do several (as a good introductory organic chemistry lab should), you have the opportunity to learn how to do distillations in the presence of another person who will catch your mistakes. At the graduate/professional level, you are supposed to know what the common mistakes are and avoid them entirely.
Things that could negatively impact a simple distillation:
- The joints are not sealed and the vaporized liquid escapes.
- No means of encouraging nucleation during boiling is used and the liquid in the still pot bumps.
- Your still pot has a star fracture and shatters when heated.
- Your variable transformer blows a fuse, and you have no heat.
- Your variable transformer is set too high and you superheat your liquid (and it bumps) and apparatus.
- Your thermometer is not placed low enough into the neck of the 3-way adapter and you do not record accurate temperatures.
- You forget to turn on the water in your condenser and you collect no distillate.
- You (against someone's better judgement) try to distil something that thermally decomposes and the apparatus catches fire, explodes, or something otherwise disastrous occurs. At the very least you do not get the distillate you though you were getting.
- You distil to dryness, and the apparatus superheats.
- You distil an ether to dryness and the residual peroxides explode.
- You start to take apart your apparatus before it has cooled (hot glass looks identical to cold glass and has a high heat capacity so it does not radiate a lot of heat) and give yourself second degree burns.
- You fill your still pot more than halfway, which prevents there from being enough room to establish a good liquid-vapor equilibrium, causing the liquid to superheat and bump.
- You get the idea.
I don't want to be a total downer. If you had told me that you were interested in theoretical or computational chemistry, I would have told you to read up on analytical and physical chemistry and apply to a program in theoretical and computational chemistry. You do very little wet-lab work in those subfields of chemistry. However, since food science involves a lot of wet-lab work, you need to have some preliminary hands-on experience.