JP2001198553A - Treatment process for organic food waste - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic food waste treatment process which comprises an intermediate treatment process for subjecting organic food waste discharged from a kitchen, any of various factories, or the like, to intermediate treatment at the discharge site without generating any malodor by preventing the waste from being putrefied, to obtain an intermediate treated material, and another treatment process for economically subjecting the intermediate treated material to drying treatment to convert the dried material into a high quality feed or fertilizer. SOLUTION: This treatment process comprises subjecting organic food waste to lactic acid fermentation so as to prevent the waste from being putrefied, to obtain an intermediate treated material, and then, while partly subjecting the resulting fermentation products formed in the intermediate treated material, such as lactic acid, and residual organic matter originally existing in the waste, to oxidative decomposition by koji mold, drying the intermediate treated material by utilizing the heat generated from metabolism of the koji mold to convert the dried material into a high quality feed/fertilizer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a food waste discharged from kitchens, various food factories, etc. mainly composed of organic substances.
Regarding the method of making feed while preventing rancidity, especially by using useful strains of the food industry such as lactic acid bacteria and koji bacteria,
A method for reliably and economically treating organic food waste.

[0002]

2. Description of the Related Art Organic food waste discharged from kitchens, various food factories, and the like has been used as feed for pigs in the past, but now it is difficult to collect and putrefaction.
It is hardly used because of bad smell. For this reason,
Although it has a high value as a breeding / fertilizer, it is mostly treated as waste.
It requires a lot of money for disposal. In addition, some waste is used as feed after heat treatment and drying, and after processing (rendering) in high-temperature oil, it requires a large amount of heat source and is not necessarily used widely. Has not been reached. In addition, a bad smell during the treatment process is also a serious problem.

On the other hand, in recent years, composting apparatuses for stabilizing the decomposition by utilizing the decomposition activity of microorganisms have been developed and used, but the equipment becomes considerably expensive, the maintenance cost is high, and the composting is required as waste. It is currently higher than the cost of processing. For this reason, development of an economical treatment method of organic food waste and a method of rearing and fertilizing has been awaited.

[0004]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to intermediately treat organic food waste discharged from kitchens, various food factories, etc. at the discharge site without generating bad odor by preventing spoilage. It is an object of the present invention to provide a method for carrying out an economical drying treatment of the obtained intermediately treated product and converting the resulting intermediately treated product into high-quality feed and fertilizer.

[0005]

Means for Solving the Problems To achieve the above object, in the present invention, in order to prevent spoilage of organic food waste, lactic acid fermentation is first performed to obtain an intermediate treated product,
Next, while utilizing fermentation products such as lactic acid generated in this intermediate product and some organic substances originally present in the waste by oxidative decomposition by Koji bacteria, the heat generated by the metabolism of Koji bacteria is utilized. It is dried and turned into feed and fertilizer.

[0006] Lactic acid fermentation may occur spontaneously by blocking air, but in order to promote lactic acid fermentation stably and efficiently, a lactic acid bacterium is added as a starter or a lactic acid bacterium serving as a growth substrate for the lactic acid bacterium. It is effective to add sugars such as sugar.

[0007] The intermediate treatment product, which prevents the generation of odor and putrefaction by the treatment with lactic acid bacteria, is subsequently treated with koji fungi and the like,
The final processed product is obtained by drying and stabilizing. In the treatment of Aspergillus oryzae, it is effective to adjust the water content to 80% or less by heat drying and / or addition of roughage such as bran or rice bran. Furthermore, it is also effective to add a previously cultured Koji fungus as a starter or simply heat sterilize an intermediate treatment product subjected to lactic acid fermentation in advance in order to facilitate the koji fungus culture. It is also effective to adjust the final water content of the processed product by applying heat to ensure the quality of the feed and fertilizer.

[0008] Although it has been clarified that lactic acid bacteria have been used for the production of fermented foods and have been useful for silage production, intermediates for feeding and manure of food waste have been reported. It has never been used to stably produce, and no attempt has been made to add lactic acid bacteria or various saccharides that promote the growth of lactic acid bacteria to promote this. In addition, aspergillus oryzae is widely used for fermented food production, but its starch and protein degrading enzyme activities are used, and little attention has been paid to the drying effect by heat of metabolism. The present invention is a food waste discharge site, an intermediate treated product that is easy to store and transport while preventing decay of organic food waste by lactic acid fermentation,
Furthermore, it has been clarified for the first time that organic food waste can be efficiently and economically reared and fertilized by treating it with a koji fungus under aerobic conditions.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to preferred embodiments of the method for treating organic food waste of the present invention. The present inventors have conducted intensive studies to solve the above-mentioned problems of the prior art, and found that lactic acid fermentation treatment is the best for preventing spoilage, and to promote lactic acid fermentation efficiently. Found that the addition of sugars such as sucrose, lactose (whey), glucose, fructose and invert sugar was extremely effective. First, the method of treating lactic acid bacteria will be described.

Organic food wastes composed of vegetables, root vegetables, cereals, meats, etc. are excellent growth substrates for microorganisms. Will occur. In order to prevent spoilage, it is necessary to store at a low temperature or use a bactericide or the like, but storage at a low temperature is difficult in terms of cost. Further, when a fungicide or the like is used, it cannot be used as a feed or fertilizer. In order to secure the way to use as feed and fertilizer, safe food-based microbial treatment is effective, but among them, lactic acid bacteria that have been used since prehistoric times are most suitable. In some cases, lactic acid fermentation can be started even when the organic food waste is not left in contact with the air, and the lactic acid fermentation can be started more reliably by adding a very small amount of lactic acid bacteria as a starter. The amount of lactic acid bacteria to be added is 10 ⁵ to ¹⁰ 10 per kg of organic food waste.
About the number is preferable. Below this range, the effect is low, and above this range, there is a disadvantage in terms of cost. In addition, it is unnecessary when the sugar content is high, but when treating organic food waste having a low sugar content, it is extremely effective to add a saccharide such as sucrose, which serves as a growth substrate for lactic acid bacteria. The amount of saccharides added depends on the type of organic food waste, but is preferably about 10 to 100 g per kg of waste. Below this range, the effect is low, and above this range, there is a disadvantage in terms of cost. As a container for performing lactic acid bacteria treatment,
A normal container that does not leak water may be used, but a container that can be covered or covered so that air does not enter is preferable.

The lactic acid fermentation treatment is usually carried out at an organic food waste discharge site in each kitchen or each food factory, to obtain an intermediately processed product, and particularly in the case of a small scale or a kitchen or the like, to carry this out. In addition, it is efficient to perform the koji fungus treatment and the drying treatment in the centralized treatment facility. In large food factories, it is possible to further treat the intermediate product at the discharge site with koji fungi.

At present, 12 genera are known as lactic acid bacteria.
acillus, Bifidobacteriu
m), Streptococcus, Lactococcus, Leuconost
oc), Pediococcus and the like can be used.

Next, the koji fungus treatment step will be described.
The lactic acid fermentation treatment step can be stably advanced by adding a very small amount of lactic acid bacteria or saccharides as a starter, but the koji fungus treatment requires a higher degree of control. That is, since the growth rate of koji bacteria is slower than that of lactic acid bacteria, in the process of koji fungi, for example, there is a high possibility that toxin-producing molds and various undesired bacteria will grow. In order to prevent this, it is effective to heat sterilize the lactic acid fermentation product in advance, but the higher the temperature, the more disadvantageous in cost. On the other hand, at low temperatures, the sterilization effect is low. For this reason, the temperature between 50 ° C. and 80 ° C. is generally excellent, but if there is another heat source, the higher the sterilization temperature, the better.

[0014] By heat sterilization as described above, the growth of undesired microorganisms can be prevented. However, for efficient growth of Aspergillus, the moisture control of the lactic acid fermentation product is most important. . In other words, lactic acid bacteria are anaerobic microorganisms that do not require oxygen.However, the growth of Koji bacteria requires an efficient supply of oxygen. It is important that air can enter freely. For this reason, it is desirable to evaporate the water by heat treatment or to mix the roughage with low water content to adjust the water content to an optimum value. Examples of the roughage with low water content include bran and rice bran. The optimum water content depends on the type of organic food waste, but is preferably 80% or less.

After heat sterilization at such a not so high temperature to adjust the water content, seed koji fungi are added for treatment. Koji fungi to be used are those used for brewing, etc., and various that do not produce toxins, such as Aspergillus
(Aspergillus), Mucor, Monascus
scus) and Rhizopus are used. When a seed koji is added, a solid koji using bran or the like as a medium is usually suitable, but a liquid culture or a spore can also be used. The amount of seed koji depends on the type of organic food waste, but in the case of solid koji,
It is desirable that the weight ratio is about one thousandth to one tenth of the organic food waste. The larger the amount added, the better, but disadvantageous in terms of cost.

After the seed koji is added, the growth of the koji and the decrease in water content are awaited. However, oxygen must be supplied in order to promote the growth of the koji, so that the air is stirred continuously or intermittently to remove air. It is important to supply. In addition, the temperature of the treated material increases due to metabolic heat as the koji grows. However, it is desirable to control the temperature to about 30 to 60 ° C. by adjusting aeration and the like. If the temperature is too high or too low, the growth of koji fungi will be slow. At the time when the growth of the koji fungus is completed, the water content is finally adjusted by heating or the like to obtain a feed / fertilizer product. As a container for culturing koji, a cylindrical rotary kiln type container or various reaction containers for compost production can be used.

As explained in detail above, lactic acid fermentation treatment of organic food waste prevents rot and
It is an intermediate product that can be easily stored and transported.This product can be taken out, collected as needed in a centralized treatment facility, and further decomposed to produce lactic acid and other lactic acid by treating it with koji. By reducing the water content, it has become possible to convert it to feed and fertilizer economically.

[0018]

EXAMPLES Next, the present invention will be described in more detail with reference to examples, but the following examples do not limit the present invention. (Intermediate treatment of organic food waste) (Examples 1 and 2 and Comparative Example 1) Cabbage, apple, dried fish and cooked rice are cut into several millimeters, and the mixture of the same weight is immersed in water, and the water is lightened. After cutting, it was used as model organic food waste. First, in the treatment with lactic acid bacteria, four plastic waste containers (containing about 1 liter) each containing 500 g of the above model waste were prepared. For one, the inner lid was left as it was and a 500 g weight was placed thereon (Comparative Example 1). Another is yogurt 5 which is commercially available as lactic acid bacteria.
g was added and mixed in the same manner (Example 1). Further, 5 g of commercially available yogurt and 10 g of sugar were added and mixed, and the same procedure was performed (Example 2). To the remaining one, 10 g of commercially available yogurt and 20 g of sugar were added and mixed, and the same procedure was performed (Example 3). Keep these four containers at room temperature (about 25
° C), and after 12 hours, 24 hours, 36 hours,
After 60 hours, the pH was measured, and the odor and leachate generation were examined. The results are shown in Table 1.

[0019]

[Table 1]

In the case where nothing was added, malodor started to be generated already in 24 hours (Comparative Example 1), but in the case where yogurt was added, the generation of malodor was remarkably suppressed (Example 1). When sugar was added at the same time, no odor was generated after 24 hours, and almost no odor was generated after 60 hours (Example 2). On the other hand, when the amount of added yogurt or sugar was increased, the effect of preventing the generation of offensive odor was recognized, but it became clear that a large amount of leachate was generated (Example 3). The pH was shown to decrease rapidly in the yogurt and sugar addition system.

(Treatment of Intermediate Treatment) (Example 4) To the model waste of Example 1 above, 1/100 weight of yogurt and 1/50 weight of sugar were added and mixed at a weight ratio of 25 ° C. For 36 hours, the air was cut off and the mixture was allowed to stand to obtain an intermediate product, and this intermediate product was subjected to the treatment of Aspergillus oryzae. The intermediate waste of the model waste is kept at 80
At 30 ° C for 30 minutes, spread in a shallow plastic container with many small holes at the bottom at a thickness of about 3 cm,
The mixture was left at 36 ° C. for 36 hours. The treated product showed little change in appearance, but a slight odor was observed.

Example 5 The same weight of bran was added to the intermediate product obtained in Example 4 and the mixture was treated at a temperature of 80 ° C. for 30 minutes, and then placed in a shallow plastic container having many small holes at the bottom. It was spread with a thickness of about 3 cm and left at 30 ° C. for 36 hours. Although no odor was generated in this processed product, several types of mold were generated.

Example 6 The same weight of bran was added to the intermediate product obtained in Example 4 and treated at a temperature of 80 ° C. for 30 minutes, and then a commercially available rice koji was reduced to 1/50 by weight. The mixture was added, spread in a shallow plastic container having a number of small holes at the bottom with a thickness of about 3 cm, and left at 30 ° C. for 36 hours. It was confirmed that the treated product did not generate any offensive odor, white koji fungi grew on the whole, and the moisture content of the treated product was reduced to about 20%.

Next, a procedure for implementing the present invention on a practical scale will be described. First, for waste discharged from small kitchens, etc., a container (for example, a plastic container) with a capacity that can store at least one day's discharge at the discharge site and that is provided with an inner lid to block air is used. Prepare and put in food waste every time it is discharged. After or preferably after each addition, a predetermined amount (a predetermined ratio) of a lactic acid bacterium starter, saccharides such as sucrose and the like are mixed and stirred, and the inside cover is shut off as much as possible with the inner lid.

The processed lactic acid bacteria are collected, transported to a centralized treatment facility, and subjected to a koji fungus treatment. To the collected lactic acid-fermented products, first, in order to control the overall water content, those containing little water such as bran and rice bran and having a value as a feed and fertilizer are added. This is introduced into a processing device similar to a rotary kiln type processing device or a compost manufacturing device provided with a ventilation stirring mechanism, and simple sterilization is performed at a temperature of about 80 ° C. by heated air or direct heating. Although simple heat sterilization can be omitted in some cases, it is necessary to confirm by a test whether it can be omitted. Next, this is cooled to about 40 ° C., and then propagated using a bran koji or the like as a starter, and subjected to a koji fungus treatment under aeration and stirring conditions. The aeration and agitation may be performed continuously or intermittently, but it is desirable to control the temperature to about 35 to 45 ° C. by utilizing the heat of metabolism of Aspergillus oryzae. If a koji bacterium having high heat resistance can be used, the temperature can be further increased.

The completion of the koji fungus treatment can be determined by monitoring the decrease in fermentation temperature and the concentration of carbon dioxide in the exhaust gas. That is, when the temperature approaches the temperature of the introduced air or when the carbon dioxide concentration of the exhaust gas is significantly reduced, the koji fungus treatment is terminated.

After the completion of the koji fungus treatment, the final adjustment of the water content is performed with heated air or the like, and the treatment is terminated to obtain the desired feed and fertilizer. In order to prevent the growth of various germs, the above koji fungus treatment is usually performed in a batch treatment every one time. However, when an apparatus such as a rotary kiln is used,
It is also possible to use a continuous extrusion flow type and to process continuously.

[0028]

As described above, according to the present invention, organic food waste which has been disposed of at a high cost until now can be easily treated at the discharge site without generating odor. It is an intermediate product that can be easily stored and transported, and if necessary, is carried into a centralized processing facility for processing, making it possible to use it as a feed and fertilizer at low cost.
It has high practical value in terms of environmental protection.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C05F 11/08 C12N 1/20 D C12N 1/14 E 1/20 F B09B 3/00 ZABC D (71) Applicant 500029707 Satoshi Hanada 1-3-1 Higashi, Tsukuba-shi, Ibaraki Pref.Industrial Technology Research Institute of Biotechnology and Industrial Technology (72) Inventor Kazunori Nakamura 1-3-1 Higashi, Tsukuba-shi Ibaraki Pref. ) Inventor Yoichi Kamagata 1-3-1 Higashi, Tsukuba, Ibaraki Pref.Industrial Technology Research Institute of Biotechnology and Industrial Technology (72) Inventor Satoshi Hanada 1-3-1 Higashi, Tsukuba City, Ibaraki Pref. (Reference) 2B150 AA03 AB20 AC01 AC05 AC06 AC07 AC08 AD22 CD37 DC13 4B065 AA21X AA30X AA39X AA49X AA60X AA66X AA69X BB15 BB16 BB23 BB26 BC31 BC34 BC37 BC50 BD08 BD10 BD41 BD50 CA43 CA55 4D004 AA03 AA04 BA04 CA04 CA15 CA18 CA19 CA22 CA42 CA46 CA48 CB04 CC07 CC15 DA03 DA09 DA10 4H061 AA02 CC42 CC55 DD20 EE61 EE66 GG48 LL26

Claims (9)

[Claims] 1. An organic food waste, comprising adding a lactic acid bacterium as a starter and / or a saccharide as a growth substrate of the lactic acid bacterium to an organic food waste and subjecting the lactic acid bacterium to an intermediate treatment by fermentation. Processing method. 2. The organic food waste according to claim 1, wherein as the lactic acid bacteria, at least one selected from the group consisting of lactic acid fermented foods, lactic acid bacteria cultures, and lactic acid bacteria dried cells is used. Processing method. 3. The organic substance according to claim 1, wherein at least one selected from the group consisting of sucrose, lactose (whey), glucose, fructose, and invert sugar is used as the saccharide. Food waste treatment method. 4. The organic foodstuff according to claim 1, wherein 10 ⁵ to 10 ¹⁰ lactic acid bacteria are added per 1 kg of organic food waste in a container capable of blocking air. Food waste treatment method. 5. Sugars per 10 kg of organic food waste
The method for treating organic food waste according to any one of claims 1 to 4, wherein 100 g is added. 6. The intermediate product obtained in claim 1 is treated under aerobic conditions with Aspergillus, and water is removed from the intermediate product by heat and / or heat of metabolic fermentation of Aspergillus, thereby stabilizing the product. A method for treating organic food waste, comprising: 7. The method for treating organic food waste according to claim 6, wherein the water content of the treated product is adjusted to 80% or less by heat drying and / or addition of roughage. 8. The method for treating organic food waste according to claim 6, wherein a koji fungus cultured in advance is added as a starter. 9. The method for treating organic food waste according to claim 6, wherein the intermediate product is heat-sterilized in advance.