Is vinegar & baking soda an effective agent for disinfecting bacteria and mold?

Question

I've seen a lot of references on the Internet stating that vinegar mixed with baking soda is an effective way to disinfect mold, bacteria, etc. I'm skeptical that it has a significant effect because vinegar (and the result of mixing baking soda: sodium acetate) is not a particularly strong acid, and I expect that the acidity is the only disinfectant activity in this mixture.

However, many people tout the magic of vinegar and baking soda as a household cleaner.

Here's a sample quote:

Wikipedia

Vinegar, historically, has been reputed to have strong antibacterial properties. One test by Good Housekeeping's microbiologist found that 5% vinegar is 90% effective against mold and 99.9% effective against bacteria,[45]

And another:

White distilled vinegar is a popular household cleanser, effective for killing most mold, bacteria, and germs, due to its level of acidity. Cleaning with white distilled vinegar is a smart way to avoid using harsh chemicals. You’ll also be glad to know that it is environmentally friendly and very economical.

And another

Baking soda and vinegar kills all food germs and bacteria including E-coli and salmonella, naturally and safely.

A report from the University of Florida suggests that a mixture vinegar + lemon juice + baking soda results in a statistically significant reduction in tested bacteria, though it appears to be significantly less effective than the other cleaners tested.

How effective is vinegar & baking soda as a disinfectant?

Answer 1

Things only need to be slightly acidic to kill bacteria. vinegar, IIRC has a pKa of 4.7, and is pretty acidic (depending on the concentration). Most bacteria have a small pH range (6 to 8 usually) for survival, due to the pH ranges of constituent enzymes.

According to this, vinegar isn't a disinfectant. It only gets rid of most microbes, but not all, unlike bleach/hydrochloric acid. Disinfectants

Vinegar is good as a preservating agent, though. It's got enough acidity to kill of the majority of the bacteria, and doesn't really harm us.

Baking soda makes it better, as it makes the solution basic. The reason baking soda on its own isn't that good is that it contains both Na+ and HCO3- ions. Dissolving it isn't that good as the acidic HCO3 conflicts with the basic Na. But, on reacting it with acetic acid, the HCO3 leaves as a gas (CO2). So we get a basic solution. The acetate ions are not that good at inhibiting the Na, so its slightly better than sodium bicarb solution.

Aside from that, basic solutions do not affect metal surfaces. Acidic solutions do.

References/calculations for the bicarb thing:

Vinegar seems to be 5%-ish acetic acid, depending upon the type. Using its density as 1.049, we get 0.05*1.049=0.052 grams in 1L water, giving us a 8*10^-4 molar solution. An extremely dilute solution dissociates nearly completely, so we get a pH of ~4.8.

Bicarb has a pKa1 of 6.3, pKa2 of 10.3. pH is average of these two, so we get pH=6.3 on its own. Not as effective as vinegar.

But, if we mix them, we get 8*10^-4 molar sodium acetate. The exact opposite happens, and we get a pOH of ~4.8, or a pH of ~9.2 at STP. So its more basic than plain bicarb. Both pure vinegar and vinegar+baking soda will be just as effective in killing bacteria, as they are +/- 2.2 pH from neutrality, and most bacteria in the atmosphere will thrive in nearly neutral conditions like the atmosphere. The only difference is that a basic solution