Introduction

Fresh meat is easily damaged as a result of chemical and enzymatic reactions and the activity of microorganisms, especially bacteria. A common way to keep meat fresh is by its refrigerating and freezing. However, various ways of application are combined or not combined with refrigeration and freezing in the hope that the shelf life of fresh meat will be longer [1, 2]. The long shelf life of fresh meat is necessary, especially for long trips, for example, on a long cruise, you certainly need food that is suitable for consumption over a long period of time. Shipping will be able to reach its destination successfully, on time, safely, and securely if all existing infrastructure and supporting components are properly fulfilled. One support that is very vital and related to welfare and health is the quality and quantity of food ingredients.

Cows are livestock whose main product is meat or milk [2]. The availability of beef needs to be supported by proper storage techniques. Beef is a product favored by the public and is a very good source of animal protein. As a food ingredient with high nutritional value, beef is a fertile medium for the growth of bacteria and fungi, so proper attention must be paid to handling meat [1, 3]. Meat and its processed products are perishable foods because they are very susceptible to contamination by spoilage microorganisms and pathogenic microorganisms. Meat and its processed products contain good nutrition for humans. These nutrients are also an excellent growth medium for microbes. Meat and its processed products are easily subject to microbiological damage because of their high nutritional and water content, and they contain lots of vitamins and minerals. Microbiological damage to meat is mainly caused by the growth of spoilage bacteria. Some physical signs of damage to meat include discoloration, odor (smelling rancid or smelling bad), the formation of mucus, and a sour taste [4].

Fresh meat contains bacteria originating from equipment, processing, workers, and water [5]. Succeeded in isolating several bacteria was found in fresh beef namely, Pseudomonas, Lactobacillus, and Brochothrix thermosphacta. These bacteria have the potential to cause spoilage because of their activity in degrading protein because meat has a high protein content [6]. Protein is used by bacteria for metabolism. Factors that cause the growth of these microorganisms can be inhibited by preservation or preservation. Preservation can protect the meat from damage or decay due to microorganisms. The pickling process should be carried out safely without reducing the quality of the meat. Preservation aims to extend the shelf life of meat before consumption. There are three methods of preservation, namely physical, biological, and chemical. Physical preservation by withering (draining blood for 12-24 hours after slaughter), heating, and cooling. Biological preservation uses microbes that produce antibacterial substances, while chemical preservation is divided into the preservation of natural active ingredients and chemicals (sodium nitrite salt, sodium acetate, etc.). The most widely used preservation method for meat is by controlling the storage temperature (cooling and freezing). Refrigeration and freezing can inhibit and limit enzymatic reactions, and chemical and physical damage to beef. Cooling is a process when the temperature of the material is lowered from -1 ᵒC to 8 °C, while freezing is a process when the temperature of the material is lowered below its freezing point and water undergoes a phase change to become ice crystals. Raw food ingredients support the growth of pathogenic microorganisms and spoilage microorganisms so the temperature has an important role in inhibiting the growth of these microorganisms. The growth of Pseudomonas, which is a spoilage bacterium in beef, occurs in storage at 1-7 °C for 1-12 days [7]. One effort that can be made to preserve meat is to store it in the freezer in the refrigerator. However, public awareness of storing meat in the freezer is still low [8]. Most people, especially traders, still store meat at refrigerator temperature. In addition to cooling, packaging is a method of preservation or preservation. Furtehrmore, the packaging used for storage is very influential on the quality of beef. Processing and storage factors that can be controlled by packers include light, concentration, oxygen, moisture content, heat transfer, contamination, and microorganisms [9]. Plastic packaging is widely used with the consideration that this material is easy to shape as desired, is not corrosive (easily corroded), and does not require special handling. In the world of trade, it is known that there are special plastics for packaging food (food grade) and plastic for packaging non-food materials (non-food grade). Therefore, if you are going to choose plastic for packaging ingredients and food products, especially meat, you should choose food grade. Packaging using vacuum plastic bags is an effort to prevent bacterial contamination, extend the storage life of meat, and is an opportunity for a more effective aging process. Some things that need to be considered in the process of packaging meat with a vacuum include cleanliness and sanitation, temperature during the cooling and storage process. Meat that is dark in color or with a high level of acidity (pH) should not be packed in a vacuum bag. By controlling cleanliness, packaging, meat temperature, and storage room temperature, the shelf life of meat can be extended from one week to several weeks. Based on existing phenomena, it is very important to keep meat fresh, especially on long journeys that require food that can be consumed in a short time. Accordingly, the author wants to know more about the differences in meat storage using a vacuum, freezer, and a combination of vacuum and freezer against spoilage bacteria.

Material and Methods             

This research is an experimental study, with the design "Post Test Only Control Group Design" which aims to find out whether there are differences in storing meat in freezing, vacuum and freezing and vacuum packaging in the presence of bacteria in the decomposition process. This research uses primary data and quantitative methods, namely a process of finding knowledge that uses data in the form of numbers as a tool to analyze information about what you want to know. The population is beef while the sample is beef obtained from the people's market center, namely stalls selling animal meat from slaughterhouses (RPH), and then brought using a thermos.

Charan et al. (2015) [4] argured that the sample size is calculated using the Resource Equation Modeling method [10], where it is not possible to make assumptions about the size, effect, and description of the standard deviation because there are no previous findings.

• E = total amount of meat − total number of treatment groups
• 18 = (n × 6) – 6
• n = 4
• The total sample is 4×6 = 24

The sampling technique was samples or specimens of the beef outer muscle (Longissimus dorsi) obtained from Surabaya RPH (Slaughterhouse) with a weight of 250 grams each. Then it will be stored at room temperature, in the freezer, and partly packaged first in plastic packaging and vacuumed, and then stored in the freezer. This research was designed using a completely randomized design (CRD) with a 5×3 factorial pattern, namely with 6 types of storage and packaging (left open at room temperature, stored in the refrigerator, freezer, packed in plastic that has been vacuumed and left at room temperature, packed in plastic which has been vacuumed and put in the freezer) and 3 kinds of treatment storage time, namely 5 days (fresh meat as control), 10 days and 15 day, and then it was seen that there was a decomposition process based on a physical examination and examination for the presence of spoilage bacteria which was carried out at the Microbiology Laboratory, Faculty of Medicine, Hang Tuah University, Surabaya.

In this study, the independent variables were temperature and packaging while the dependent variable was the process of spoilage as seen from the physical changes in the meat and the discovery of spoilage microorganisms.

Table 1: Bacterial colony normality test on observation day

Table 2: Bacterial colony normality test on meat packaging

Table 3: Meat odor normality test

Results and Discussion

Comparison of bacterial colonies based on research groups

From the bacterial colony normality test in the table below, it was found that the research data were normally distributed in meat samples with different packaging on days 5, 10, and 15 with a p-value> 0.05 (Table 1 and 2).

Comparison of meat odor based on research groups

From the meat odor normality test at the table below, it was found that the research data were normally distributed on meat samples on days 5, 10, and 15 with a p-value >0.05 (Table 3 and 4).

From the results of the odor test research in the table above, it was found that meat that was vacuum packed and placed in the refrigerator and freezer had a better test than meat products that were not packaged and placed in the open air or placed in the freezer and refrigerator.

Comparison of meat color by research group

From the meat color normality test at the table below, it was found that the research data were normally distributed on meat samples on days 5, 10, and 15 with a p-value >0.05 (Table 5 and 6).

From the results of the meat color test research in the table above, it was found that meat that was vacuum packed and placed in the refrigerator and freezer had a better test than meat products that were not packaged and placed in the open air or placed in the freezer and refrigerator.

Comparison of meat texture based on research groups

From the meat texture normality test at the table below, it was found that the research data were normally distributed on meat samples on days 5, 10, and 15 with a p-value >0.05 (Table 7 and 8). From the results of the texture test research in the table above, it was found that meat that was vacuum packed and placed in the refrigerator and freezer had a better test than meat products that were not packaged and placed in the open air or placed in the freezer and refrigerator.

Comparison of bacterial colonies based on research groups

From the bacterial colony normality test, it was found that the research data were normally distributed in meat samples with different packaging on days 5, 10, and 15 with a p-value >0.05. The test was continued using the two-way ANOVA test, with the results showing that there were significant differences in bacterial colonies on the day of observation and meat packaging with a p-value <0.05.

Table 4: Meat odor descriptive analysis of packaging

Table 5: Meat color normality test

Table 6: Meat color descriptive analysis of packaging

There was also a relationship between meat packaging and the day of observation on the growth of bacterial colonies with a p<0.05 value. This is in accordance with research conducted by Hernando [11]. Which concluded that the factors that influence the growth of microorganisms in meat include temperature and the presence or absence of oxygen. Temperature is a factor that should be considered to regulate bacterial growth because the higher the temperature the greater the growth rate. Prihharsanti (2016) [12] state that, the average number of bacteria in meat storage at room temperature, refrigerator, and freezer at different times, an increase in the number of bacterial colonies was found to stand out in meat that had been stored for 9 hours at room temperature, whereas in refrigerator storage and freezer, bacterial spores are inactivated. At room temperature, the number of bacteria after being stored for 9 hours increased very rapidly, but the other treatments did not. Furthermore, research conducted by Rahayu et al. (2022) that beef that was placed at room temperature for 0 hours, 3 hours, 6 hours, and 9 hours experienced a significant increase in the number of bacterial colonies. This is because the chemical composition and moisture of meat are ideal for bacterial life processes to take place and proteins are used by microorganisms through enzymatic metabolic processes. Bacteria will grow by dividing twice every 30 minutes so that the longer the meat is left at room temperature the bacteria will continue to multiply in the meat relatively quickly [13]. The number of bacterial colonies in storage in the refrigerator and freezer did not show a significant difference [14], so it appears that the bacteria that live in the two places have not grown up to 18 hours of storage. At room temperature, it began to appear to increase at 6 hours of storage and at an interval of 6 hours to 9 hours the fastest growth. The effect of temperature is mainly on the activity of enzymes produced by bacteria in catalyzing the biochemical changes that occur inside and outside the cell. At low temperatures, the growth of bacteria is inhibited, even though to a certain extent the bacteria do not experience death, these bacteria are called psychrophilic bacteria.

This bacterium is present in meat stored in the refrigerator. Bacterial death at low temperatures is caused by changes in the colloidal state of the protoplasm that are not reversible [12].

Comparison of meat odor based on research groups

The results showed that meat samples left in the open air showed a daily increase in odor intensity. Whereas in the meat samples that were vacuumed and placed in the refrigerator and freezer, the odor intensity remained unchanged even up to the 15^th day [15]. The factor that affects taste is the smell detected by the nose, Dina et al. (2017) [16] stated that the aroma of

beef is influenced by the type of feed given when the cow is alive. An abnormal aroma will usually be smelled immediately after the animal is slaughtered. This can be caused by abnormalities, including sick animals and animals on medication. Sick animals, especially those with acute inflammation of the internal organs, will produce meat that smells like rancid butter. Animals in the treatment period, especially with antibiotics, will produce meat that smells of medicine. Odor evaluation is highly dependent on the taste panel. The process of spoilage in meat is characterized by the activity of microorganisms that destroy fat and protein in meat. The activity of microorganisms such as fungi and bacteria is carried out using enzymes (enzymatic) because bacteria need fat and protein in their metabolic processes. Researchers usually calculate the level of spoilage in meat by detecting the ammonia compound (NH3) resulting from the decomposition of meat protein-ammonia gas is also one of the causes of the pungent smell of rotting meat [16, 17].

Table 7: Meat texture normality test

Table 8: Meat texture descriptive analysis of packaging

Comparison of meat color by research group

The color change in the meat samples left in the open air had occurred since the 5^th day of the study and reached a maximum since the 10^th day. Meanwhile, the color changes in the meat samples stored in a vacuum and placed in the refrigerator and freezer remained until the 15^th day of the study. The main determinants of meat color are the concentrations of myoglobin and hemoglobin, where myoglobin differs between muscles (red and white), age, species, nation, and muscle location. Several factors also affect the color of raw meat, including the sex of the animal, how to cut the meat, the water-holding capacity of the meat, drying on the surface of the meat, decay on the surface of the meat, and light hitting the surface of the meat. The paler color of the meat is affected by the increase in bacteria every hour [18, 19]. Discoloration of meat can also be associated with aerobic or anaerobic bacterial contamination. The high demand for oxygen for aerobic bacteria in the logarithmic phase of growth results in the formation of metmyoglobin, resulting in a discoloration effect. The increase in the number of aerobic bacteria causes the surface of the meat to change color from oxymyoglobin red to metmyoglobin brown, and then to purple and black due to reduced myoglobin. The color of bright red meat will turn brown or gray due to oxidation compounds or the presence of H2S produced by bacteria [18, 20-21].

Comparison of meat texture based on research groups

Changes in the texture of the meat samples occurred in samples placed in the open air even from the 5^th day of the study, whereas in the other 5 sample groups, there was no change on the 5^th day. Meat samples that were placed in the open air experienced the maximum changes in texture since day 5 of the 10^th study, while samples that were vacuumed and placed in the refrigerator and freezer did not experience changes in texture until the 15^th study day.  Meat texture is determined by the myofibril protein content which is related to pH and water-holding capacity. Microbial activity at room temperature will degrade the protein structure in the meat so that the texture of the meat will change. At refrigerator and freezer temperatures, microbial activity decreases and the number of microbes decreases over time. Vacuum packaging also reduces the risk of contamination with outside air [22, 23]. In research conducted by Firdaus [17]. The texture did not change in stored meat samples.

Conclusion

There was a significant difference in bacterial colonies on the day of observation and meat packaging where the least number of bacterial colonies was found in meat with vacuum packaging and stored in the refrigerator. Also found a relationship between meat packaging and the day of observation on the growth of bacterial colonies. For odor-intensity and color change in meat samples that were left in the open air, more and more showed an increase in odor intensity and meat color changes. Whereas in the meat samples that were vacuumed and placed in the refrigerator and freezer, the odor intensity and color of the meat remained unchanged even up to the 15^th day. Changes in meat texture have occurred in samples placed in the open air since the 5^th day of the study, whereas the samples that were carried out in a vacuum and placed in the refrigerator and freezer did not experience a change in texture until the 15^th day of the study.

Acknowledgments

This study was supported by Hang Tuah University. We express our gratitude and appreciation to the Hang Tuah University, Surabaya, Indonesia.

Disclosure Statement

No potential conflict of interest was reported by the authors.

Funding

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Authors' Contributions

All authors contributed to data analysis, drafting, and revising of the paper and agreed to be responsible for all the aspects of this work.

ORCID

Risma

https://orcid.org/0009-0002-3432-8664

Djatiwidodo Edi Pratiknya

https://orcid.org/0009-0002-6393-0603

HOW TO CITE THIS ARTICLE

Risma*, Djatiwidodo Edi Pratiknya, The Differences in Meat Storage Using a Vacuum, Freezer, and a Combination of Vacuum and Freezer against Spoilage Bacteria. J. Med. Chem. Sci., 2024, 7(2) 326-335.

DOI: https://doi.org/10.26655/JMCHEMSCI.2024.2.5

URL: https://www.jmchemsci.com/article_182707.html