These two kinds of food preservatives have a common feature - large yield and wide use. By convention, let's look at the basic properties first:

"Sodium Benzoate" white powder, slightly benzoin odor, soluble in water, ethanol, molecular weight 144.12

"Potassium sorbate" white powder, odorless or slightly smelly, soluble in water, ethanol, molecular weight 150.22

The second is the scope of use of food additives GB2760-2014:

"Sodium benzoate" can be used in preserves, confectionery, seasonings, beverages (especially carbonated beverages) and other fields, with slightly fewer applications

"Potassium sorbate" can be used in cheese, preserves, candy, bread, pastries, cooked meat products, beverages, seasonings, soyproducts, wine and other fields, the application scene is rich

Let's start with the older sodium benzoate:

sodium benzoate is an acidic preservative, the best pH range is 2.5-4.0, when the pH of food > 4, the preservative effect is very weak.

The reason is that sodium benzoate plays a bacteriostatic role, mainly relying on acid conditions not dissociated sodium benzoate, it is easier to penetrate the cell membrane, interfere with the cell membrane, inhibit the cell respiration enzyme, and then inhibit microbial reproduction.

Sodium benzoate has a wide range of bacteriostatic, can inhibit the reproduction of yeast, mold and some bacteria.

So what foods have a pH between 2.5 and 4.0?

The answer: highly acidic foods, such as carbonated drinks, vinegar and soy sauce;

Limitation of use

In addition to the food field, sodium benzoate is the preferred preservative for many liquid pharmaceutical products. However, sodium benzoate is not suitable for use in meat products because of the pH range and the reaction with some substances in meat products.

The safety of sodium benzoate has been controversial in recent years. For example, according to the toxicological index of oral LD50 in rats, sodium benzoate was 2700mg/kg and potassium sorbate was 4920mg/kg (FAO/WHO, 1994).

At present, sodium benzoate is a food preservative allowed in GB2760, which shows that the Health Commission recognizes the safety of sodium benzoate in food at this stage.

Let's talk about potassium sorbate

potassium sorbate is an acidic preservative. The antiseptic effect is best when the pH is lower than 5 and Potassium sorbate is still good at PH 5-6.

Under acidic conditions, undissociated potassium sorbate can penetrate cell membrane and inhibit intracellular dehydrogenase, thus affecting microbial reproduction.

The "leaky fish" of potassium sorbate, anaerobic bacillus (common in vacuum-packed foods), can be combined with Nisin for preservative effect.

Application case

Vilcon red Sausage potassium sorbate, Lactostreptococcus, sodium dehydroacetate, sodium nitrite

"Hope Barbecue Sausage" potassium sorbate, Lactostreptococcus, sodium nitrite, sodium nitrate, sodium dehydroacetate, sodium diacetate

Limitation of use

With the increase of potassium sorbate concentration, the bacteriostatic rate of potassium sorbate increased obviously. Taking meat enema as an example, the maximum allowable amount of potassium sorbate is 1.5g/kg.

Potassium sorbate can be said to be a food preservative brother, very wide use. Studies have shown that the residual amount of potassium sorbate in the hind legs of slaughtered pigs is 0.069g/kg (Yushan Ma.2006), while the maximum allowable residual amount of potassium sorbate in cooked meat products (except meat sausage) is 0.075g/kg.

The problem of exceeding the standard of potassium sorbate is common in the food industry. How to reduce the dosage, improve the antibacterial effect, still need to combine some compounding knowledge, this aspect will be discussed in detail in the future article.