Total Plate Count of Traditionally Produced Smoked Skipjack in Ambon

In Ambon City, smoked skipjack is very popular and is one of the people’s daily sources of protein. Smoked skipjack is classified as a ready-to-eat food ingredient. As a ready-to-eat product, the food safety aspect of smoked skipjack is a scientific fact that must be identified and disclosed so that people can consume it safely. The aim of this research was to determine the safety of smoked skipjack products produced in three production center villages in Ambon City based on the total plate count (TPC) value. The research applied exploratory method and was carried out in two stages: 1) conducting observations at six smoked skipjack home industries in three villages; 2) performing an analysis of the total plate count (TPC) of the smoked skipjack. The TPC analysis was carried out in the Fisheries Products Technology laboratory at Pattimura University. The total plate count (TPC) of smoked skipjack from three home industries in Ambon City is at a safe level for consumption, namely from TPC 3,8 x 102 CFU g−1 to 1,4 x 104 CFU g−1. Smoking is done traditionally with the same facilities and processes except for the form of smoked fish and the way it is displayed when sold.


Introduction
At present, sea food has a good position as a source of daily protein for people in various parts of the world [1,2] thereby potentially increasing the income of fishermen and coastal communities [2][3][4][5][6][7].The sea waters of Ambon City are one of the productive fish producing areas in Indonesia, including skipjack.Skipjack is an economically important type of fish and is one of the export commodities that provides significant foreign exchange income.Skipjack is very popular with the public because it contains various nutritional contents and tastes delicious.Skipjack is not only sold fresh, but is also undergoing a smoking process to prevent spoilage and extend its shelf life.
In Ambon City, smoked fish is generally prepared from skipjack and is known by the local name cakalang asar.Asar comes from the word smoke which is a term from the local Maluku community which is related to processing using smoke.Traditional smoking applies the hot smoking method using natural fuels such as wood, coconut shells and coconut husks.This process of is carried out traditionally and is still applied by the people of Ambon City, Maluku.Traditional smoking is very simple and has been carried out for generations by coastal communities, especially during the fishing season [2,4,8,9].The smoking process causes the fish flesh to become dry, golden brown, and has a distinctive smoky taste and aroma.The distinctive smoky taste and aroma of smoked fish comes from natural smoke compounds from organic fuel that stick to the surface layer of the fish.[2,8,10].
Smoked skipjack has a delicious taste, is very popular with consumers, is a daily source of protein for people in Ambon, and is one of the superior foods in Maluku [2,4,11,12] [13], and also in various other places [14][15][16][17][18][19].As one of the superior products, smoked skipjack is also popular as a souvenir for people who want to travel out of the region and for guests from other regions who will return home [12].Several locations in Ambon City are known as smoked skipjack production centers, 1329 (2024) 012012 IOP Publishing doi:10.1088/1755-1315/1329/1/012012 2 including the villages of Hative Kecil, Silale and Gunung Malintang.In each of these villages, there are several home industry producers who are involved in processing smoked skipjack as a permanent source of income and they have been doing this for generations.
Smoked skipjack is a semi-moist food with a maximum shelf life of three days.The water content is still quite high, allowing the activity of spoilage microorganisms to continue in smoked skipjack, especially at tropical environmental temperature such as in Ambon City.[20,21] stated that fish have high water activity (aW) so that bacteria can easily breed.In addition, sales without packaging allows microbial contamination from the environment of traders and consumers.[13] highlighted that in general the implementation of sanitation and hygiene when selling smoked skipjack still needs to be improved.
Smoked skipjack is classified as a ready-to-eat food ingredient.As a ready-to-eat product, the food safety aspect of smoked skipjack is a scientific fact that must be identified and disclosed so that people can consume it safely [22][23][24].[25] stated that every human being has the right to adequate food and has access to food that is nutritious and safe for health.Bacterial contamination can occur from the processing process to sales, which not only causes damage, but can also cause health problems (food-borne diseases).[15,26,27] stated that smoked fish contaminated with bacteria is very dangerous for the health of people who consume the fish directly without processing it.One of the scientific information that is an indicator of food safety is the number of bacterial contaminants in food products, known as the total plate count (TPC).Thus, it is necessary to carry out TPC analysis on smoked skipjack to determine the presence of bacteria which is an indicator of deterioration in the quality and safety of the product for consumption.The aim of this research was to determine the safety of smoked skipjack produced in three villages producing smoked skipjack in the Ambon city based on the total plate count (TPC) value.

Research Procedure
The method used in this research was descriptive observation method.The research was carried out in two stages, from June to July 2019.In stage 1, observations were made of the smoking process at six home industry producers in three (3) smoked skipjack production center villages in Ambon City, namely Hative Kecil, Silale and Gunung Malintang.Direct observations were carried out on all home industry producers in the three villages to observe production facilities, smoking and sales processes.During the observation, interviews were also conducted with smoked skipjack producers.In stage 2, total plate count (TPC) analysis was carried out on samples of smoked skipjack in the Fishery Products Technology laboratory.TPC analysis was conducted using standard testing methods used in laboratories.

Total Plate Count (TPC) Test
The TPC test was carried out aseptically to prevent unwanted contamination and was done in duplo to increase the accuracy of the results obtained.TPC of bacterial colonies in samples was carried out at each dilution as needed.Before performing the TPC test, all tools used must be sterilized in an oven at 180°C for 2 hours.The bacterial medium was sterilized in an autoclave at 121 °C and 1 Atm pressure for 15 minutes.After the sterilization, the media temperature was maintained at 45-55°C in a water bath to prevent the media from freezing.The diluent solution was prepared by dissolving 8.5 grams of NaCl in 1 liter of distilled water and sterilized in an autoclave at 121 °C for 15 minutes.The test began with weighing 10 grams of smoked fish sample, grinding it, and dissolving it in a sterile diluent solution until it reached a volume of 100 mL to obtain a dilution of 10 1 .Next, 1 mL of the solution was taken and put into a test tube containing 9 mL of sterile dilution solution to obtain a dilution of 10 2 , and it went on with the same procedure until a dilution of 10 5 was obtained.From each dilution test tube, 1 mL was taken using a pipette, and put into a sterile Petri dish; this was done using Duplo.A total of 15 mL of PCA was poured into each Petri dish.Afterwards, the Petri dish was shaken in a circle on the table so that the PCA media and sample are evenly distributed.After the PCA in the Petri dish was frozen, the Petri dish was placed in an inverted position in an incubator at 35 °C for 48 hours.After incubation, bacterial colonies in each Petri dish were counted.The number of bacteria that could be counted in a Petri dish was 30 -300 colonies [21].

The process of smoking and selling smoked skipjack
The villages of Hative Kecil, Silale and Gunung Malintang are some of the very productive villages as smoked skipjack production centers in Ambon City.The results of observations on six (6) home industry producers in the three (3) production center villages mentioned above show that the processing of smoked skipjack is carried out traditionally using the hot smoking method.The characteristics and processing processes are relatively the same, regardless of the facilities used, the stages of the production process and the sales.The differentiating aspect of the home industry of smoked skipjack in these three villages is the form of the skipjack fish to be smoked and the way it is displayed when sold.In Hative Kecil village, people process the skipjack by splitting it before smoking, otherwise known as fillet skipjack.In the villages of Silale and Gunung Malintang, people smoke whole skipjack.

Facilities
Facilities used in the smoked skipjack production process include: containers for holding fish, knives, clean water, wood, coconut shells, coconut husks, smoking shelves, bamboo awls and tongs, bamboo skin binders, baking pans for selling the smoked skipjack, and many other.The water sources used are borehole, seawater and faucet water (PDAM water) provided by the government in storage tanks and distributed to residents' homes.In all production villages, smoking stoves are found with an average length of 1 to 1.5 meters, with 2 to 3 shelves.The height of each shelf is 30 to 50 cm.The width of the shelf is generally adjusted to the length of the fish to be arranged, and is generally 50 to 60 cm.The fuel used as a heat source is wood, coconut shells and coconut husks.The smoking process is open and carried out at high temperatures.In general, all facilities as described above are used in the three production villages.This is because all home industry producers in the production village smoke fish traditionally using the same process, except for the form of smoked skipjack and the way it is displayed at the time of sale.Smoked skipjack production facilities at 3 production locations are presented in the table below.

Production Process
Processing of smoked skipjack in Ambon City is done traditionally and is known as "cakalang asar".
The stages of the smoked skipjack production process begin with selecting raw materials for fresh skipjack measuring 30 -50 cm and for good quality fish.Good quality skipjack will result in delicious smoked skipjack and can be stored for a longer time.In general, the stages of the smoking process are the same in the villages of Hative Kecil, Gunung Malintang and Silale, except for handling the smoked form of fish, in which Hative Kecil produces fillet smoked skipjack, while Silale and Gunung Malintang villages produce whole smoked skipjack.
The initial treatment after the skipjack arrives at the production site is that the fish is weeded to remove the gills and entrails, washed with running water until clean, and soaked in salt water.The home industry in Hative Kecil Village produces whole fillet smoked skipjack, which means that the skipjack fish is split into two parts from tail to head.Next, it is pierced with two (2) small bamboo sticks from one of the widest sides until it penetrates the other side; this is to avoid halves of fish from coming off during the smoking process.In the top and bottom center, two (2) bamboo slices which are longer than the length of the fish are placed; this is intended as a sturdy support so that the smoking and selling process can take place without touching the fish flesh.After this stage, the fish is drained for a few moments and then placed on the smoker shelf to be smoked.Home industries in the villages of Silale and Gunung Malintang produce whole smoked skipjack, where before being smoked the skipjack is placed on a wooden cutting board and pressed using the palm of the hand to release the liquid from the fish flesh to make it thinner.Next, the fish is pierced with a bamboo skewer from head to tail and ready to be smoked.The bamboo skewer functions as the part that will be held to turn the fish during the smoking process.
The smoking stove consists of two (2) to three (3) shelves.The distance from the smoke source to the fish ranges from 30 to 100 centimeters and the smoking process on a smoking stove takes 2 to 3 hours.The smoking stove is prepared by placing fuel in the form of wood and coconut shells under the stove at the very bottom of the smoking shelf.Next, all the fuel is burned until it produces embers, then coconut fiber is added.This smoke source is distributed evenly on all sides of the stove facing the shelf where the smoked fish is arranged.The skipjack that has been drained is arranged on the shelf closest to the smoke source.The smoke source is arranged in such a way that it only produces smoke (not fire) evenly across all the skipjack.
The smoking temperature is controlled for fish by adjusting the distance between the shelf and the smoke source.The smoking temperature ranges between 50 -150 °C, where the temperature is highest for fish placed on the first shelf (closest to the fire source).Periodically the fish are turned over to cook both sides of the smoked fish.After the outside of the fish looks like it is starting to cook (30 -50 minutes), the fish are moved to the shelf above to cook the center of the fish at a slightly lower temperature, while the bottom shelf is arranged with other fresh skipjack about to be smoked.Arranging fish on a higher shelf or at a lower temperature is intended to perfect the fish cooking process.The further the distance between the fish on the rack and the fire source, the lower the temperature.The smoking process, which starts on the first shelf and ends on the top shelf, lasts 2 to 3 hours depending on the size of the fish being smoked.Once all the fish is completely cooked, the smoke source is extinguished and the fish is left to cool on the top shelf.The traditional smoking of skipjack in Ambon can be seen in Figure 1.

Selling
The selling of whole smoked skipjack originating from the villages of Silale and Gunung Malintang takes place at the Mardika traditional market.Smoked skipjack that has been cooked and cooled is arranged vertically in a baking dish by sticking a bamboo skewer through the head at the bottom of the pan and the tail at the top (Figure 2, left).Meanwhile, whole fillet smoked skipjack from Hative Kecil village is sold at the smoked fish shop in Hative Kecil village.Displaying the whole fillet smoked skipjack that is split is done by placing it on a table with the skin side down and the flesh on the top in a horizontal position; Smoked skipjack is arranged in layers (Figure 2, right).The selling of smoked skipjack, both whole and fillet, are carried out unwrapped.Based on the results of interviews, it is known that consumers are more interested in unwrapped smoked skipjack so they can choose the kind they want.This also shows that consumers in Ambon City are skilled enough to distinguish between good quality fish or vice versa.The amount of smoked skipjack production is adjusted to the average number of sold each day to avoid sales on the second and third days.
In general, the smoked skipjack production process in Ambon City has been well carried out.Based on the results of interviews, it is known that smoked skipjack is produced every day to meet public demand.This shows that smoked skipjack is still one of the favorite choices for daily protein sources for people in Ambon City.Besides family consumption, smoked skipjack is also in demand as gift for people who want to travel out of the area and for guests from other areas who will return back to their area [12].In general, the traditional smoking process in Ambon city is almost the same as the reported fish smoking process smoking fish is carried out for 30 minutes to 3 hours [17,22,27].

Total Bacterial (Total Plate Count (TPC)) of Smoked Skipjack
The freshness of the raw materials is very important to get a good quality of smoked skipjack that is safe for consumption.Apart from the freshness of the skipjack, the availability of facilities, the right production process, and adequate sanitation and hygiene aspects also influence the quality and safety of the smoked skipjack produced.The results of observations in home industries in three production villages show that the production process has been going quite well in several aspects above.[10,[27][28][29] stated that the smoking process in high temperatures (hot smoking) can reduce humidity, reduce microorganisms, and affect the quality and food safety of smoked products.[2] reported the nutritional content of traditional smoked skipjack from the village of Hative Kecil, Gunung Malintang and Silale, Ambon City, which comprise of 31.97% of protein, 4.38% of fat, 1,695 of ash, 60.34% of water content, 1.46% of carbohydrates and 173 of energy calories.Fish smoking is a preservation process that combines the processes of salting, drying and smoking [14,27,30] During the smoking process, volatile compounds from wood smoke penetrate, thereby reducing the number of bacteria in the fish and producing a specific smell and taste of smoke.Total plate count has an important role in determining the number of microbes that contaminate food ingredients.The TPC value is an indicator of the decline in quality and suitability of food products for consumption.Data on TPC test results for smoked skipjack from 6 home industry producers in three production center villages can be seen in Table 2.
The results of this research showed that the total bacteria in smoked skipjack from 6 home industry producers in 3 production center villages, namely Hative Kecil, Silale and Gunung Malintang villages in Ambon City are in the range of 3.8 x 10 2 CFU/gram to 1.4 x 10 4 CFU/gram.This result is still below the standard set by the National Standards Agency (BSN) in the Indonesian National Standard (SNI), namely a maximum of 1.0x10 5 colonies per gram [31].The results of this research indicated that smoked skipjack in Ambon City is suitable and safe for consumption.Smoked skipjack producers in Ambon City understand the importance of providing smoked skipjack is in good quality and safe for consumers.The TPC value for smoked fish in Ambon City as shown in the Table 2, is apparently better than smoked fish in Bulukumba Regency, South Sulawesi which reached 3.7x10 6 CFU/gram [32].Based on the total bacterial count in Table 2, it is known that the smoked skipjack produced in Ambon City is at a good food safety level and is suitable for consumption.The lowest value or best TPC figure was found in smoked skipjack from Silale village, namely 3.8 x 10 2 to 4.9 x 10 2 CFU/gram.The low TPC value at this location is related to the handling and washing processes carried out in Silale village using greater amount of running water so that the skipjack and all equipment are cleaned properly.Moreover, the smoking time is longer (160 minutes) and the distance between the fish and the smoke source is closer (maximum 75 cm) compared to the other two production centers (Table 1).Smoking is a method of processing and preserving food at high temperatures to kill bacteria so that the freshness of the fish can be maintained and its shelf life can be increased.[10,22,27] highlighted that the smoking process can destroy most of the bacteria, either spoilage or pathogenic bacteria.
Preserving fish by smoking is based on the components of heat and smoke on microorganisms and changes in the basic components of fish muscle.In addition, the amount of water in the flesh is reduced, and this is reflected in the quality of smoked fish products [10,14,17].Many components of smoke, namely organic acids, alcohols, aldehydes, ketones and phenols in particular, have bacteriostatic and/or fungistatic effects on several types of bacteria and/or fungi [10,23,24,29,33].

Conclusion
The total plate count (TPC) of smoked skipjack from three production centers in Ambon City is at a safe level for consumption, namely within the TPC value of 3.8 x 10 2 CFU/gram to 1.4 x 10 4 CFU/gram.Smoking is done traditionally with the same facilities and processes, except for the form of smoked fish and the way it is displayed when sold.

Figure 2 .
Figure 2. The selling of smoked skipjack in traditional markets.Left, whole skipjack; Right, fillet whole skipjack

Table 1 .
Production facilities for smoked skipjack