JPH04360807A - Disinfection treatment using nisin - Google Patents

Abstract

PURPOSE:To provide an easy and efficient disinfection treatment process utilizable e.g. for the disinfection in the dressing of meat-collecting animal. CONSTITUTION:Meat is immersed in an aqueous solution of nisin at 40-70 deg.C for 1-5 min or washed with the aqueous solution. Gram-positive bacteria and Gram-negative bacteria are surely disinfected by this treatment.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sterilization method using an aqueous solution containing nisin.

0002

[Prior Art] In many industries, such as sterilization process when slaughtering animals for meat, food processing process, cleaning of food processing equipment, cleaning of medical equipment, hygiene control during animal and fish breeding, etc., it is necessary to produce high quality products. There is a tendency for demand to increase. In many cases, large-scale automation has been pursued to ensure increased production, maintain high quality, and reduce processing costs.

[0003] In this type of industry, because it is involved in food and medical care, it is essential that the product be safe from hygiene and microbial contamination, and that it can be used in a wide range of fields. The development of a simple and highly efficient sterilization method is desired. The peptide antibacterial substance nisin is a U.S. F.
It is a highly safe substance approved as a food additive by the DA (Federal Register/vol.
．． 53, No. 66/Wednesday, April
6, 1988/pages 11247 to 11251), used as a preservative for dairy products and to prevent lactic acid bacteria contamination during the brewing of alcoholic beverages (US Pat. No. 4,597,972).
No. 4584199, European Patent No. 186498
(See No., etc.)

However, although nisin has an excellent bactericidal effect against certain Gram-positive bacteria, it is thought to have a poor bactericidal effect against Gram-negative bacteria. Gram-negative bacteria often coexist with Gram-positive bacteria and are the main cause of food spoilage and contamination, and this bactericidal property of nisin poses a major problem when using nisin for sterilization purposes. was.

[0005]

SUMMARY OF THE INVENTION The purpose of the present invention is to develop a simple and efficient sterilization method using nisin that can be used in a wide range of fields.

[0006]

[Means for Solving the Problems] The present inventors have conducted extensive research in order to achieve the above object. As a result, we found that heating treatment with a nisin-containing aqueous solution significantly improves the bactericidal effect against not only Gram-positive bacteria but also Gram-negative bacteria.Based on this knowledge, we completed the present invention. It's arrived.

[0007] According to the present invention, there is provided a sterilization method characterized in that when sterilizing by immersion or washing in an aqueous solution containing nisin, the temperature of the aqueous solution is 40 to 70°C. Nisin used in the present invention is Streptococcus lactis (Streptococcus lactis).
It is a peptidic antibacterial substance produced by various strains of B. uslactis (Advances in
Applied Microbiology, vol.
27, pages 85-123, 1981),
Apline & Barr
et Ltd., USA).

[0008] It can also be obtained by culturing Streptococcus lactis having the ability to produce nisin, and then isolating and purifying the culture by a commonly used method known per se (Journal of Gene).
ral Microbiology, vol 88,
pages 189-192, 1975). The concentration of nisin in the sterilized aqueous solution is not particularly limited, but is usually 0.1 to 1000 μg/ml, preferably 1 to 100 μg/ml.
A range of μg/ml is appropriate.

[0009] Sterilization treatment with an aqueous solution containing nisin is usually carried out at a temperature of 40 to 70°C, preferably 55 to 70°C. The sterilization treatment time varies depending on the nisin concentration, treatment temperature, and field to be sterilized, but is not particularly limited.
A suitable time is usually 10 seconds to 120 minutes, preferably 1 minute to 5 minutes.

As mentioned above, the sterilization treatment can be carried out by immersion in a heated aqueous solution containing nisin for a certain period of time, or by washing with the heated aqueous solution for a certain period of time. Fields of application of the present invention include sterilization processes during slaughtering of meat animals such as chickens, turkeys, cows, and pigs, food processing processes, food processing equipment cleaning, medical equipment cleaning, hygiene management during animal and fish breeding, etc. There are many fields that require hygienic and sterile conditions.

[0011]

According to the method of the present invention, it is possible to reliably kill not only Gram-positive bacteria but also Gram-negative bacteria, for which it has been thought that nisin's bactericidal efficacy is inferior. For example, the genus Salmonella, the genus Escherichia, the genus Pseudomonas, the genus Alcaligenes
bacteria such as Salmonella gallinarum (Salmonella gallinarum).
arum), Salmonella cholerasius (Salm
Salmonella choleraesuis, Salmonella typhyllium
phimurium), Escherichia brunellis (
Escherichia vulneris), Escherichia hermanii (Escherichia he
rmannii), Escherichia coli (Esche
richia coli), Pseudomonas aeruginosa
a) , Pseudomonas cateria
nas cattleyae), Pseudomonas dacunhae,
Alcaligenes aquamarinus (Alcaligen)
es aquamarinus), Alcaligenes
Marshalies (Alcaligenes marsha)
llii), Alcaligenes eutrophus (Alc
Gram-negative bacteria such as Aligenes eutrophus) can also be reliably sterilized.

0012

【Example】

Example 1 10 ml of L medium (composition: 5 g of yeast extract, 10 g of tryptone, 5 g of NaCl dissolved in 1 liter of distilled water) was
Dispense into 4φ test tubes, sterilize at 121°C for 15 minutes, inoculate each strain listed in Table 1, and inoculate at 37°C for 8 minutes.
Cultured for hours. Bacterial cells were collected from the obtained culture solution by centrifugation, washed with sterile water, and then a cell suspension (bacteria count: 109/ml) was prepared with sterile water.

[0013] Nisin (Applied Micr
obiology Inc. 20mM Tris-HCl buffer (pH 7) heated to each temperature listed in Table 1.
．． 3) Add 100 μl of the bacterial suspension prepared above to 900 μl.
μl was added and treated for the various times listed in Table 1. After the heating treatment, the bacteria were collected by centrifugation, washed with sterile water, diluted to an appropriate culture ratio, and spread on the L medium containing 2% agar. After culturing at 37°C for about 24 hours, the number of colonies formed was measured to determine the number of viable bacteria. Note that the number of viable bacteria before the heating treatment was also calculated in advance from the number of colonies formed using the same method.

The bactericidal effect was evaluated by calculating the percentage of viable bacteria from the ratio of the number of viable bacteria before and after the heating treatment thus measured. The results are shown in Table 1. As is clear from Table 1,
In the case of nisin addition treatment at 40 to 70°C, a bactericidal effect that was approximately 10 to 1000 times higher than that in the case of 20°C treatment was observed. Further, in the case where nisin was not added, a large number of bacterial cells survived even when treated at 70°C, but when nisin was added, the number of surviving bacteria was 0.4% or less for all bacterial strains.

[0015]

[Table 1]

Claims (1)

[Claims] Claim 1: When immersing or washing and sterilizing in an aqueous solution containing nisin, the temperature of the aqueous solution is 40 to 70℃.
A sterilization method using nisin characterized by carrying out at ℃.