JP2021061830A - Washed baby leaf manufacturing method, washed baby leaf bacterium number reducing method and packaged salad manufacturing method - Google Patents

Abstract

To provide a method of reducing the bacterium number of a washed baby leaf.SOLUTION: A washed baby leaf bacterium number reducing method includes a step of selecting damaged leaves in the manufacture of washed baby leaves. The washed baby leaf bacterium number reducing method further comprises the steps of: preferably performing the selection after the baby leaves are transported, and preferably washing the selected baby leaves that are not damaged; and removing water from the washed baby leaves. More preferably, the washed baby leaf bacterium number reducing method performs the first selection after the harvesting of the baby leaves and before the washing of the baby leaves and performs the second selection after the washing.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for producing washed baby leaf, a method for reducing the number of bacteria in washed baby leaf, and a method for producing a packaged salad.

In recent years, ready-to-eat vegetables have become more popular, and for example, leafy vegetables packed in bags or cups, cut vegetables, salads, and the like. This is because these products have already been washed and sterilized, which saves the trouble of washing.

However, ready-to-eat vegetables have various problems, such as disposal of unsold products and difficulty in controlling orders. The cause of these problems is that the expiry date of ready-to-eat vegetables is short because they are fresh foods.

Therefore, a technique for improving the expiration date of instant vegetables has been developed, and an example is as follows. Patent Document 1 discloses a method for preserving cut vegetables. Specifically, when storing cut vegetables, a bactericidal solution is attached and then washed with water.

Patent Document 2 discloses a method for producing leafy vegetables. Specifically, when the leaves are stored, a bactericidal solution is attached, the bactericidal solution is applied, and then the leaves are washed with water.

Japanese Unexamined Patent Publication No. 2004-655149 Japanese Unexamined Patent Publication No. 2008-237208

An object to be solved by the present invention is to reduce the number of bacteria in washed baby leaf. The number of fungi in baby leaf is generally high after harvesting and after storage. This tendency is especially strong in the hot summer months.

In order to solve this problem, the present inventors diligently studied and discovered the relationship between the damage of baby leaf and the number of bacteria. The present invention is defined from such a viewpoint as follows.

It is a method of manufacturing washed baby leaf, which is composed of at least a sorting process, and what is sorted here is at least baby leaf, and the sorting criteria is whether or not it is damaged. is there.

In addition, it is a method for reducing the number of bacteria in washed baby leaf, which is composed of at least a sorting process, and at least baby leaf is sorted here, and the sorting criteria are damaged. Whether or not.

The sorting step is preferably after the baby leaf has been transported. Further, it is preferable to have a step of washing the selected baby leaf and a step of removing water from the washed baby leaf. Then, the selected baby leaf may be stored, or may be washed after the storage.

Further, sorting may be performed after washing, or water may be removed after washing and then sorting may be performed.

Further, the sorting may be performed in two stages of the first sorting and the second sorting. The first selection is done after harvesting the baby leaf and before washing the baby leaf. The second sorting is done after the washing step.

For these sorted damaged leaves, the increase in the number of general viable cells 72 hours after the production of washed baby leaf is preferably more than 2.0 orders. More preferably, the increase in the number of general viable bacteria 72 hours after the production of washed baby leaf is greater than 1.0 order.

The baby leaf produced in this way may be packaged in a container. The non-defective rate of baby leaf in the containerized salad thus obtained is 80% or more, and the non-defective rate is the weight ratio of the undamaged baby leaf in the packaged salad.

The mechanism by which the effects of the present invention are obtained is presumed to be as follows. In the damaged leaf, the water inside is squeezed out from the damaged part, and the growth of bacteria is likely to occur from there. The fungus grown in this way also attaches to other leaves. Since the number of bacteria in baby leaf increases in this way, it is presumed that the number of bacteria in baby leaf can be reduced by removing the damaged leaves.

What the present invention makes possible is to reduce the number of bacteria in washed baby leaf. By reducing the number of bacteria in baby leaf, the storage stability of washed baby leaf is improved. In particular, the number of bacteria can be stably lowered even in a high temperature period such as summer. Such washed baby leaf can be eaten without subsequent washing.

Flow chart of the manufacturing method of washed baby leaf according to this embodiment Examples of damaged and undamaged leaves Changes in the number of general viable bacteria over time in damaged leaves Changes in the general viable cell count of baby leaf in summer Changes in the general viable cell count of baby leaf before and after process improvement

<Baby leaf>
Baby leaf means leafy vegetables about 10 to 90 days after sowing. When the term "baby leaf" is used in the present application, the type of baby leaf does not matter, and specifically, one type of baby leaf or a mixture of several types of baby leaf may be used. The size of baby leaf varies depending on the type of plant and is not limited, but is 4 cm or more and 15 cm or less, preferably 12 cm or less, more preferably 10 cm or less from the viewpoint of ease of eating.

The plant used for baby leaf is not particularly limited as long as it is edible, and examples thereof include cruciferous, amaranthaceae, asteraceae, umbelliferae, liliaceae, and chenopodiaceae. Specific examples include sunny lettuce, green curl, salad na, mizuna, beet, mustard, green mustard, arugula, spinach, red mustard, romaine, red oak, tarsai,
Bok choy, loro rossa, red Asian mustard, pino green, white kale, red kale, Detroit, Pakchoi, etc.

<Containered salad>
The packaged salad according to the present invention (hereinafter, referred to as “containered salad”) refers to a salad that is packaged and contains at least washed baby leaf. The temperature zone in which the packaged salad is distributed is preferably the so-called chilled (refrigerated) zone. The chilled zone is a distribution temperature zone, which is a temperature zone of 10 ° C. or lower that does not freeze. Preferably, it is from −5 ° C. to 5 ° C.

<Manufacturing method of washed baby leaf and manufacturing method of packaged salad>
FIG. 1 shows the flow of a method for producing washed baby leaf and a method for producing a packaged salad. The configurations of both manufacturing methods are the same. That is, the production method mainly comprises cultivation and harvesting (S10,) transportation (S20), sorting (S31), and water removal (S40).
Cleaning (S50), water exposure (S60), water removal (S70), sorting (S32), and containerization (S80). These steps can be omitted, added, or changed as needed.

<Cultivation and harvesting (S10)>
The method of cultivating baby leaf is not particularly limited, and examples thereof include hydroponics, soil cultivation, open field cultivation, and closed plant factory cultivation. Hydroponics has the advantages of being less affected by the weather and having less bacterial adhesion. Cultivation in a closed plant factory is also preferable from the viewpoint of hygiene and stable production. Here, what is incorporated as a baby leaf cultivation method and a manufacturing method is
It is the content described in JP-A-2017-060441. Baby leaf cultivated in this way is harvested. The harvesting method is not particularly limited, and is, for example, a person, a machine, a combination thereof, or the like.

<Transportation (S20)>
One of the purposes of transporting harvested baby leaf is cleaning. The transportation method is not particularly limited, and is, for example, container packing, bag packing, cardboard packing, and the like. However, from the viewpoint of reducing the moisture adhesion rate of baby leaf, it is preferable to pack it in a packaging material having a dehumidifying effect during transportation.

<Selection (S30)>
The criterion for selecting baby leaf is whether or not the baby leaf is damaged. Damaged means that the baby leaf (leaves and petioles) is broken, chipped, cut, the tissue structure inside the leaf is damaged, or discolored due to withering. It is at least one of the states. When the tissue structure inside the leaf (for example, the water storage cells of the leaf) is damaged, the water in the leaf exudes. When the water in the leaves exudes, the damaged part of the leaves turns dark green. Details of the selection criteria will be described later. By removing the damaged baby leaf, the number of bacteria in the baby leaf can be reduced. This is because the fungus grows easily on the damaged leaves.

<Cause of damage>
The causes of damage to baby leaf are physical and chemical effects. The physical effects are the effects of contact between leaves, contact between leaves and containers and equipment, contact between leaves and liquids such as water, and contact between leaves and humans. The chemical effect refers to the effect of a chemical substance, for example, a chemical substance contained in a cleaning solution.

<Details of selection criteria 1>
As for the baby leaf to be removed, the increase in the general viable cell count after 72 hours from the production of the washed baby leaf is more than 2.0 orders. Washed baby leaf As a leaf whose increase in the number of general viable bacteria exceeds 2.0 orders after 72 hours from the production, the leaf whose internal structure is conspicuously damaged (large damage) and the leaf with two or more cuts (large damage). Waste leaf) and the like.

<Details of selection criteria 2>
Preferably, the increase in the number of general viable bacteria 72 hours after the production of washed baby leaf is 1.
It is larger than 0 order. In addition to the above-mentioned large damaged leaves and waste leaves, the leaves with less damage (small damage) and leaves with one cut (cut leaves) have an increase in the number of general viable bacteria on the order of 1.0 after 72 hours. And so on.

<Sorting time 1: Sorting before cleaning>
From the above point of view, the time to sort baby leaf is after the process in which baby leaf is physically or chemically affected. Specifically, after harvesting the baby leaf and before cleaning the baby leaf, and more specifically, after transporting the baby leaf. Before storing baby leaf. This is because the transportation of baby leaf causes damaged leaves, and storage increases the number of bacteria attached to baby leaf. By sorting here, it is possible to reduce the number of bacteria in the stage before washing the baby leaf, and it is possible to stably reduce the number of bacteria in the baby leaf after washing.

<Sorting time 2: Sorting after cleaning>
In addition, the sorting is performed after washing the baby leaf. Specifically, it is after washing the baby leaf and after removing water after washing. The reason is that the baby leaf is chemically and physically affected by washing or removing water from the baby leaf, and the leaves are damaged. By sorting here, the growth of the number of bacteria after production can be suppressed.

<Sorting time 3: Sorting before and after cleaning>
Furthermore, the first selection and the second selection are performed. The first selection is after harvesting the baby leaf and before cleaning the baby leaf. The second sorting step is after washing the baby leaf. Specifically, it is after washing the baby leaf and after removing water after washing. By performing the sorting a plurality of times in this way, it is possible to reduce the number of bacteria before washing and suppress the growth of the number of bacteria after production.

<Storage (S40)>
The purpose of storing baby leaf is to improve the efficiency of transportation or production. That is, by securing a certain amount of harvested baby leaf, the number of times of transportation to the manufacturing factory and the number of times of manufacturing at the factory can be reduced. In addition, the balance between supply and demand can be adjusted, and it is possible to level the supply amount due to a good harvest or poor harvest, and to respond to an increase in the order amount. The storage temperature is 0 ° C. to 10 ° C. in order to suppress an increase in the number of bacteria in baby leaf during storage as much as possible. From this point of view, the sorted, undamaged baby leaf is stored. The storage may be before cleaning.

<Washing (S50)>
The purpose of cleaning baby leaf is to remove foreign substances and reduce the number of bacteria. Examples of foreign substances are mud, soil, sand, etc. that adhere to baby leaf. The means for cleaning baby leaf is not particularly limited, but is preferably contact with sterilizing water. The method of contacting the liquid is not particularly limited, but examples thereof include immersion and spraying. The baby leaf is washed once or twice or more. The effect of the solution used for cleaning is to reduce the general viable cell count. Such a cleaning solution is not particularly limited, but for example, hypochlorous acid, hypochlorite, chlorite, sodium hydroxide, potassium hydroxide, calcined calcium, hydrochloric acid, acetic acid, peracetic acid, citric acid. , Fumaric acid, ozone and the like, preferably hypochlorous acid, hypochlorite, and chlorite. The preferred conditions for hypochlorous acid, hypochlorite, and chlorite are concentrations of 10-200 p.
The pm and pH are 4.8 to 8.0. The pH is more preferably 5.0 to 7.0. As a result, the effect of reducing the number of bacteria is enhanced.

<Liquid contact temperature>
When contacting the sterilizing water, the temperature of the sterilizing water is 0 ° C. to 30 ° C., preferably 0 ° C. to 20 ° C., more preferably 0 ° C. to 15 ° C., and most preferably. Of
It is 0 to 10 ° C. If the temperature of the sterilized water is too high or too low, the damage to the baby leaf will be great. For example, the odor of sterilized water is likely to be attached, wilting is likely to occur, and the shelf life is difficult to last.

<Liquid contact time>
The contact time is not particularly limited, but is 10 seconds to 60 minutes, preferably 10 seconds to 15 minutes, and most preferably 10 seconds to 10 minutes. If the contact time with sterilized water is too short, it is difficult to reduce the number of general viable bacteria. On the other hand, if the contact time is too long, the damage to baby leaf will increase.

<Water exposure (S60)>
The purpose of exposing baby leaf to water is to remove the disinfectant. That is, water exposure is required when the liquid is contacted with sterilized water. In other words, this step is appropriately omitted. The means of water exposure is not particularly limited, but is preferably immersion in water, spraying of water, or the like.

<Bleached water>
The bleached water is not particularly limited, but is, for example, tap water, well water, purified water, or the like. In addition, chlorine contained in water for which necessary sanitary measures have been taken (see Water Supply Law Enforcement Regulations (December 14, 1957, Ministry of Health and Welfare Ordinance No. 45)) is not subject to removal during water exposure. ..

<Water exposure temperature>
The temperature of water exposure is 0 ° C. to 30 ° C., preferably 0 ° C. to 20 ° C., and most preferably 0 ° C. to 10 ° C. If the treatment temperature of water exposure is too high or too low, the damage to baby leaf will increase.

<Water exposure time>
The water exposure time is not particularly limited, but is preferably 1 second to 60 minutes, more preferably 5 seconds to 30 minutes, and most preferably 10 seconds to 10 minutes.
If the water exposure time is too short, the effect of removing the fungicide will be low. On the other hand, if the water exposure time is too long, the damage to baby leaf will increase.

<Water removal (S70)>
The purpose of removing water from washed baby leaf is to improve the appearance of washed baby leaf. Water removal refers to removing adhering water, specifically dehydration and drying. The method of removing water is not particularly limited, and is static, air blowing, cold air, hot air, centrifugation, suction by vacuum, use of a hygroscopic material, or a combination thereof. Considering the damage caused by the contact between baby leaves and the damage caused by the pressure caused by centrifugation, it is preferable to avoid centrifugation and dry by blowing air. The target of water removal is not particularly limited, but preferably the water adhesion rate is 3.0% or less. The details of the moisture adhesion rate will be described later.

<Moisture adhesion rate>
The water adhesion rate of baby leaf is a value obtained by multiplying the amount of water attached to the leaves by the weight of the leaves after removing the water by 100. The specific method for measuring the moisture adhesion rate is as follows. The weight (A) of the leaf with water attached is measured. Then, the water adhering to the leaves is wiped off with a paper or the like that adsorbs the water, and the weight (B) of the leaves after removing the adhering water is measured. Apply to the following formula to calculate the moisture adhesion rate.
Moisture adhesion rate (%) = 100 x (AB) / B
<Packing (S80)>
Baby leaf is packed in a container. The packaging material used for packaging is not particularly limited, but is a polyethylene bag, a polypropylene bag, a bag made of these composite materials, a plastic tray, a plastic pack, a cup, or the like. The condition that the packaged salad is satisfied is that the non-defective rate of baby leaf is 80% or more in consideration of the influence of bacterial growth after packaging. More preferably, it is 85% or more. The non-defective rate is the value obtained by dividing the weight of non-defective baby leaf (leaves without cutting, tearing, or crushing) contained in the packaged salad by the total weight of baby leaf contained in the packaged salad, at 100. It is the multiplied value.

<Number of bacteria>
The number of baby leaf bacteria measured is the general viable cell count. The method for measuring the general viable cell count is
Any known method may be used. Specifically, the Food Hygiene Inspection Guideline (Japan Food Hygiene Association, 2)
This is a pour method using a standard agar medium based on (2004). By washing (S50), the general viable cell count can be reduced by 1.0 to 3.0 orders. The general viable cell count after washing by the main washing (S50) is 1.0 × 10 ^{4 to} 1.0 × 10 ⁵ CFU / g. Viable count after the lapse of the washed mesclun produced after 24 hours is preferably 1.0 × ¹⁰ 6 CFU /
g or less, and more preferably not more than 1.0 × ¹⁰ 5 CFU / g. Further, preferred total viable count in the washed mesclun 72 hours after post-production, 1.0 × 10 ⁶ C
It is FU / g or less. This makes it possible to eat without subsequent washing. In addition, according to the hygiene standards for bento boxes and sozai (Revised Kanshoku No. 161 on June 29, 1979, Eshoku No. 188, Eiko No. 211, Eka No. 119 on October 12, 1995) ,
Viable count is less 1.0 × ¹⁰ 6 CFU / g.

It is Example 1 that embodies the baby leaf according to the present invention. These examples do not limit the scope of claims according to the present invention.

<Baby leaf>
The baby leaf used in this example is a mixture of pinogreen, spinach, beet and arugula.

<Measurement of bacterial count>
The measurement of the number of bacteria in this measurement is based on the Food Hygiene Inspection Guideline (Japan Food Hygiene Association, 200).
4 years).

<Test 1>
In Test 1, the baby leaf after harvesting is transported to a factory, washed with washing water containing hypochlorous acid, exposed to water, sucked in water by vacuum, and dried by blowing air. went. Among the dried leaves, undamaged leaves (good products), less damaged leaves (small damage), leaves with one cut (cut leaves), leaves with noticeable damage to the internal structure of the leaves (large damage), Leaves with two or more cuts (
Waste leaves), and the growth behavior of the general viable cell count over time was confirmed. The general viable cell count was measured 0 hours after drying and 72 hours after drying.

<Test 2>
In the July period (Comparative Example 1) and the May period (Comparative Example 2), the harvested baby leaf was transported to a factory, washed with washing water containing hypochlorous acid, and exposed to water. Then, after sucking water by vacuum, it was dried by blowing air. The general viable cell count was measured 0 hours after drying and 72 hours after drying.

<Test 3>
The baby leaf harvested in the July period (Example 1) and the August period (Example 2) is used as a leaf with little damage (small damage), a leaf with one cut (cut leaf), and the internal structure of the leaf. Leaves with noticeable damage (
Baby leaf with large damage) and leaves (waste leaves) with two or more cuts removed is stored in a storage, transported to the factory, washed with washing water containing hypochlorous acid, and exposed to water. After that, it was dried by applying wind. After drying, the general viable cell counts were measured at 0 hours, 24 hours, 48 hours, 72 hours, and 96 hours after drying for those selected in the same manner as described above. The non-defective rate here was 80% or more. Except for sorting, the conditions were the same as in Test 2.

<Evaluation results, summary>
As a result of considering the results of Test 1, the leaves with conspicuous damage to the internal structure of the leaves (damaged leaves) and the leaves with two or more cuts (waste leaves) have rapid bacterial growth, and 72 hours after production. It was found that the increase in general viable cell count was greater than 2.0 orders. In addition, for leaves with little damage (small damage) and leaves with one cut (cut leaves), the increase in the number of general viable bacteria 72 hours after production is about 1.0.
It turned out that it was more than the order (Fig. 3). From Test 2, it was found that the number of bacteria in the raw material baby leaf increased during the high summer temperature (Fig. 4). From the results of Test 3, the number of bacteria in washed baby leaf is reduced by removing damaged leaves whose increase in general viable cell count is more than 2.0 orders after 72 hours have passed since the production of washed baby leaf. It turned out (Fig. 5). Specifically, it was found that the number of bacteria can be reduced at the stage before washing by performing the sorting after harvesting and before washing, preferably before storage. It was also found that by removing these leaves by sorting after washing the baby leaf, preferably after removing water, it is possible to suppress the growth of bacteria after production. It was found that the expiration date can be extended by using the method of the present invention.

The fields in which the present invention is useful are a method for producing washed baby leaf and a method for reducing the number of bacteria in the washed baby leaf.

Claims (10)

A method for reducing the number of washed baby leaf, which comprises at least the following steps:
Sorting: It is at least baby leaf that is sorted here, and the sorting criterion is whether or not the baby leaf is damaged. The method of claim 1
The sorting is performed after the baby leaf has been transported. The method of claim 1 or 2, further comprising:
Cleaning: It is the sorted, undamaged baby leaf that is cleaned here.
Water removal: It is the washed baby leaf that is removed here. The method of claim 3 which further comprises the following steps:
Storage: Stored here is the sorted, undamaged baby leaf, which is stored prior to the cleaning. The method of claim 1
The sorting is performed after the baby leaf has been washed. The method of claim 5, further comprising:
Water removal: It is the washed baby leaf that is removed here. A method for reducing the number of washed baby leaf, which comprises at least the following steps:
First sorting: What is sorted here is at least baby leaf, the selection criteria is whether the baby leaf is damaged or not, and the process is after harvesting the baby leaf. And before cleaning baby leaf,
Second sorting: It is at least baby leaf that is sorted here, the selection criterion is whether the baby leaf is damaged or not, and the step is after washing. The method according to any one of claims 1 to 7.
In the damaged leaves to be sorted, the increase in the number of general viable cells 72 hours after the production of washed baby leaf is more than 2.0 orders. The method according to any one of claims 1 to 7.
In the damaged leaves to be sorted, the increase in the number of general viable cells 72 hours after the production of washed baby leaf is more than 1.0 order. A method according to any one of claims 1 to 9, further comprising the following steps:
Packaging: Here, what is packaged here is at least the selected undamaged baby leaf, and the non-defective rate of baby leaf in the resulting packaged salad is 80% or more, and the non-defective product. The ratio is the weight ratio of the undamaged baby leaf contained in the packaged salad to the baby leaf contained in the packaged salad.

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