Is Sodium Lactate a Preservative? "
Recently, I helped Aunt Wang, who runs a snack shop in the community, process a batch of handmade dried radish. However, she was very worried about it - it was crispy when it was first made, but it wilted and became a bit sticky after just two days. Aunt Wang was worried that it wouldn't sell well, so she bought a bottle of white powdered radish and said it was called" Sodium Lactate ", which could make dried radish last longer. I was stunned at the time, sodium lactate? This word sounds familiar, but it seems like I haven't heard of it before. I asked Aunt Wang, "Is this a preservative? Can it keep the food from spoiling?" She shook her head and said, "I'm not sure, I just heard the neighboring vendor mention that it's not harmful to people if it's left." This question reminded me of a question I used to confuse myself with: What exactly are preservatives? Does sodium lactate really rely on "killing bacteria" for preservation? To understand this question, I have to start with Aunt Wang's bottle of sodium lactate. She bought a small bottle of liquid, transparent, with a slight salty smell, not as heavy as soy sauce. I glanced at the bottle at the time, and the label read 'food grade sodium lactate', with only C3H5NaO3 on the ingredient list, followed by 'moisturizer, plasticizer'. Moisturizing agent? "I muttered to myself," What is the relationship between moisturizing and anti-corrosion? "In order to figure it out, I searched for some information on food knowledge notes I had learned before on my phone - the scientific name of sodium lactate is sodium lactate, which is the sodium salt of lactic acid. It is an organic compound obtained by the reaction of lactic acid and sodium hydroxide, easily soluble in water, colorless or light yellow liquid at room temperature, has no special smell, and tastes a little salty, which is its basic property. What exactly does it do? I saw in the information that the main function of sodium lactate is to "moisturize". What is moisturizing? For example, when you pickle vegetables, water always comes out of the outside because the cell fluid concentration is high and the water seeps out; If a little salt is added, it will dehydrate the cells and make the dish dry. And sodium lactate can make the water in food more "stable" through permeation - it forms a protective film on the surface and inside of the food, preventing water evaporation, just like wrapping the food with a "water film". So, Aunt Wang's dried radish may have wilted, which is indeed due to water loss. Adding sodium lactate can retain the water and keep the dried radish crispy. This logic is correct. But are "moisturizing" and "anti-corrosion" the same thing? I remember buying vacuum packed cured meat in the supermarket before, with the packaging stating 'containing preservative sodium benzoate'. That kind of preservative can really 'kill' or 'inhibit' bacteria and will not spoil over time. Does sodium lactate only moisturize and have no effect on bacteria? I then checked the data and found that the mechanism of the two things was completely different: traditional preservatives, such as sodium benzoate and potassium sorbate, directly destroyed the cell structure of microorganisms, or inhibited the activity of enzymes in cells, making bacteria "unable to live"; As for sodium lactate, its preservative effect is actually "indirect" - it increases the water activity (aw value) of food, making it difficult for bacteria to absorb water. At the same time, it is alkaline (pH about 7-8), which can make the food environment more alkaline (although the food itself may be acidic, adding sodium lactate will increase the pH value). Many bacteria, such as E. coli and yeast, which cause food spoilage, are indeed difficult to reproduce in alkaline and water deficient environments. Simply put, sodium lactate does not directly "kill" bacteria, but indirectly preserves them through an "environment that makes bacteria unable to survive". Its main role is as a "moisturizer", and preservation is a side effect. To verify this statement, I conducted a small experiment: two fresh dried radishes of the same size were taken. One was added with 5ml of sodium lactate solution (according to Aunt Wang's concentration), while the other was left at room temperature of 25 ℃ for observation. Three days later, the dried radish without added sodium lactate had become soft and collapsed, with a sticky surface and a slightly acidic odor; What about those with added sodium lactate? Although it's a bit soft, it's much better than not adding it at all. The surface still has some moisture, and there's no odor when smelled. Auntie Wang looked at the results and said, "Hey? This effect is pretty good, it can still be eaten after three days. I added, 'Actually, it mainly relies on locking in water to prevent bacteria from drinking. If you add sodium lactate and let dried radish sit for more than a week, it may still spoil - after all, it's not really' sterilizing '.'. She nodded and said, 'Then I'll try putting a little less next time, don't waste it.'.

Speaking of which, you may ask, 'Since it can help prevent corrosion, is it considered a preservative?' It depends on how we define 'preservative'. In the food industry, not everything that can extend its shelf life is called a "preservative", depending on its main function. For example, the main function of sodium lactate is moisturizing, while anti-corrosion is just an "additional benefit" in low water content and high pH environments, like an "auxiliary player", while sodium benzoate is the "main attacker", specifically responsible for inhibiting microorganisms. So strictly speaking, sodium lactate is not considered a traditional preservative, but rather a "multifunctional additive". However, it also depends on the specific scenario. I saw someone online before saying that sodium lactate is used a lot in meat products, such as sausages and cured meats, because it can keep the meat moist and tender to eat. At the same time, by adjusting the pH value, it can also extend the storage time. At this point, its preservative effect becomes even more apparent - but its fundamental purpose is still to make the meat "dry and non greasy", rather than directly relying on chemical substances to kill bacteria like sodium nitrate (which is the true preservative+coloring agent). So, we cannot simply say that it is not a preservative, but rather that its preservative effect is the second attribute and moisturizing is the first attribute. Let's talk about its security again. Food grade sodium lactate is allowed to be added by the state and is used in many processed foods from legitimate manufacturers. As long as the dosage is controlled, it is harmless to the human body. I have checked * * 2760 and it specifies the maximum amount of it to be added in different foods, such as not exceeding 30g per kilogram in meat products and 10g per kilogram in beverages. When used in pickled products like dried radish, the dosage is only "moderately added". Unlike some preservatives that may be controversial, sodium lactate is considered to be very safe, which is why Aunt Wang dares to use it. However, I have to remind you: don't expect sodium lactate to be as "divine" as preservatives. If you buy semi-finished vegetables without added sodium lactate, such as homemade pickles, and don't put them in the refrigerator in summer, even if you add sodium lactate, they may only last for an extra day or half, and are still prone to spoilage; But if a legitimate food factory uses sodium lactate and other anti-corrosion measures (such as vacuum packaging, cold chain transportation), the shelf life can indeed be extended significantly.

Now looking back at Aunt Wang's batch of dried radish, I finally understand why using sodium lactate has a significant effect - it's not because it's a "magical preservative", but because it helps the dried radish "lock in moisture", making it less likely to become soft and tasteless due to water loss, and also making it difficult for bacteria to reproduce in a water deficient environment. So, don't panic when you see the words "sodium lactate" on the package later. It is not a traditional preservative, but it can really help keep food fresh, especially for food that needs to keep moisture, such as bread, meat products, Pickled vegetables, and so on. Have you ever encountered a similar situation? When I see an additive while shopping, I always wonder what its purpose is? Or have you ever figured out a certain 'food truth' through your own experience? You can chat in the comment section, maybe we can clarify each other's doubts~