I85PREP
⌘ K
Maharashtra HSC Fish Processing Technology (Bifocal) study materials
Maharashtra HSC Fish Processing Technology (Bifocal) study resources

Maharashtra HSC Fish Processing Technology (Bifocal) practice questions

One question at a time. Build your Maharashtra HSC Fish Processing Technology (Bifocal) understanding.

First 50 of 200 questions. Each one lists the choices, the correct answer, and an explanation. The checker at the top of this page saves progress in this browser when it is available.

Continue in the practice tool above to load more questions, 50 at a time.

Question 1Fish Handling, Hygiene and Quality Control

In fish handling, rigor mortis is best described as which of the following changes in muscle?

  1. The muscle stiffens as ATP is depleted and actin and myosin lock together Correct answer.
  2. The muscle swells as water is absorbed osmotically through the gills
  3. The muscle darkens as melanin spreads from the skin into the fillet
  4. The muscle softens as connective tissue collagen dissolves in the chilled flesh

Explanation

Rigor mortis is the stiffening of muscle after death that occurs when ATP reserves fall and actin and myosin filaments lock into an inextensible actomyosin complex. It begins later and lasts longer in fish that are chilled rapidly, because low temperature slows the biochemical reactions. Handling fish during rigor, especially by rough bending, can cause gaping and texture damage.

Question 2Fish Handling, Hygiene and Quality Control

A fisherman wants to slow the onset of rigor and bacterial growth in a freshly caught seer fish on board. Which on-board practice is most appropriate?

  1. Cover the catch with wet gunny bags at ambient temperature
  2. Wash, eviscerate where permitted, and chill rapidly in ice or chilled seawater Correct answer.
  3. Stack the catch dry on the deck and delay icing until landing
  4. Keep the fish in warm seawater tanks to reduce struggling

Explanation

Rapid chilling immediately after capture slows both the onset of rigor and the multiplication of spoilage bacteria. Washing removes surface slime and blood that carry bacteria, and evisceration reduces enzymatic and bacterial load in the belly cavity. Delay in chilling allows temperature-dependent spoilage to accelerate.

Question 3Fish Handling, Hygiene and Quality Control

Which parameter is the standard measure of the keeping quality of ice used in fish chilling?

  1. The colour of the ice blocks
  2. The salt content of the melting ice
  3. The size of the ice crystals only
  4. The total bacterial count of the water used to make the ice Correct answer.

Explanation

Ice can itself be a source of contamination, so the bacteriological quality of the water used for ice-making is monitored, commonly by total bacterial count and coliform tests. Ice made from contaminated water can inoculate spoilage and pathogenic organisms directly onto the fish surface. Colour and crystal size do not indicate hygienic quality.

Question 4Fish Handling, Hygiene and Quality Control

In sensory assessment of fresh fish, which observation most strongly indicates that the fish is no longer fresh?

  1. The gills are bright red and the eyes are convex
  2. The skin is moist with a thin, clear slime layer
  3. The gills are brown and the eyes are sunken and cloudy Correct answer.
  4. The flesh is firm and springs back when pressed

Explanation

Brown or greyish gills and sunken, cloudy eyes are classic signs of advanced spoilage in sensory evaluation of fish. Fresh fish typically shows bright red gills, convex clear eyes, firm elastic flesh and a thin transparent slime. These changes reflect bacterial action and autolytic breakdown during storage.

Question 5Fish Handling, Hygiene and Quality Control

Which of the following is the main reason fish spoils faster than most mammalian meat?

  1. Fish muscle has high moisture, near-neutral pH and little connective tissue Correct answer.
  2. Fish has a higher post-mortem pH and lower bacterial load
  3. Fish contains natural antibiotics that accelerate bacterial growth
  4. Fish muscle contains more connective tissue than beef

Explanation

Fish muscle is high in moisture, has a pH close to neutral after death, and contains little connective tissue, all of which favour rapid bacterial growth and enzymatic breakdown. These intrinsic factors make fish more perishable than many other muscle foods. Natural antibiotics would slow, not accelerate, spoilage.

Question 6Fish Handling, Hygiene and Quality Control

During fish handling, cross-contamination is best prevented by which practice?

  1. Using the same cutting board for raw fish and cooked products
  2. Rinsing hands in the same water used to wash the deck
  3. Separating raw fish contact surfaces from cooked or ready-to-eat product surfaces Correct answer.
  4. Storing fish boxes directly on the floor of the processing hall

Explanation

Cross-contamination occurs when bacteria from raw fish are transferred to cooked or ready-to-eat products through shared surfaces, utensils or hands. Separating raw and cooked zones, with dedicated boards and utensils, is a core control measure. Shared boards and floor storage increase contamination risk.

Question 7Fish Handling, Hygiene and Quality Control

Which of the following best describes the role of histamine in fish quality and safety?

  1. It is a toxin formed by bacterial decarboxylation of histidine in scombroid fish Correct answer.
  2. It is a preservative added to chilled seawater systems
  3. It is a natural enzyme that tenderises fish muscle after death
  4. It is a pigment that darkens the flesh during chilling

Explanation

Histamine is produced when bacteria decarboxylate the amino acid histidine, which is abundant in scombroid fish such as tuna and mackerel. It forms when such fish are held at warm temperatures and is not destroyed by normal cooking. Control depends on rapid chilling from the moment of capture.

Question 8Fish Handling, Hygiene and Quality Control

Which temperature range is most critical to avoid for prolonged holding of fresh fish because it favours rapid bacterial growth?

  1. Between 70 and 90 degrees Celsius
  2. Between 15 and 40 degrees Celsius Correct answer.
  3. Between 0 and 4 degrees Celsius
  4. Between -18 and -25 degrees Celsius

Explanation

Bacterial growth is most rapid in the warm ambient range, roughly 15 to 40 degrees Celsius, which is why fish must be chilled quickly after capture. Frozen storage at -18 degrees Celsius or below and chilled storage near 0 degrees Celsius both slow microbial activity. High cooking temperatures inactivate bacteria rather than favouring growth.

Question 9Fish Handling, Hygiene and Quality Control

In a fish processing plant, a worker notices that a batch of chilled fish has developed a distinctly ammonia-like odour. What is the most appropriate interpretation?

  1. The fish has undergone advanced bacterial spoilage and should be rejected Correct answer.
  2. The fish is at peak freshness and the odour is normal
  3. The fish has absorbed odour from clean ice and is still acceptable
  4. The odour indicates the fish was frozen too rapidly

Explanation

Ammonia-like odours arise from bacterial breakdown of nitrogenous compounds such as trimethylamine oxide and amino acids during spoilage. Such an odour is a strong sensory indicator of advanced deterioration, and the batch should be rejected under quality control. Clean ice does not produce an ammonia odour, and freezing rate does not cause it.

Question 10Fish Handling, Hygiene and Quality Control

Which of the following best explains why fish should not be held in rigor when filleted for premium products?

  1. Filleting during rigor prevents the formation of trimethylamine
  2. Filleting during rigor increases the oil content of the fillet
  3. Filleting during rigor makes the flesh too soft to cut cleanly
  4. Filleting during rigor can cause gaping and muscle separation that reduce yield and value Correct answer.

Explanation

During rigor the muscle is contracted and tightly bound, so cutting or bending it can tear the myotomes apart, producing gaping and reducing yield and appearance quality. Filleting is therefore best done either before rigor or after resolution. Rigor does not change oil content or prevent amine formation.

Question 11Fish Handling, Hygiene and Quality Control

A quality control officer wants to verify that chilled fish has been stored within specification. Which combination of checks is most appropriate?

  1. Measurement of the fish length and weight only
  2. Only visual inspection of the fish skin colour
  3. Temperature measurement of fish core plus sensory evaluation and time-temperature records Correct answer.
  4. Counting the number of fish in each box only

Explanation

Effective quality verification combines objective temperature measurement of the fish core with sensory evaluation and documented time-temperature records. Temperature alone may miss sensory deterioration, while sensory checks alone cannot confirm cold-chain compliance. Length, weight and box counts do not indicate hygienic quality.

Question 12Fish Handling, Hygiene and Quality Control

Which of the following statements about the use of chlorinated water in fish processing areas is most accurate?

  1. Chlorinated water is used mainly to increase the weight of the fish
  2. Chlorinated water may be used for washing equipment and floors at approved concentrations, but must not contaminate the edible product Correct answer.
  3. Chlorinated water should be added directly to fish flesh to extend shelf life
  4. Chlorinated water must never be used anywhere in a fish processing plant

Explanation

Chlorinated water at approved concentrations is used for sanitising equipment, floors and surfaces in fish processing, but direct contamination of edible product must be avoided. It is not added to flesh and is not used to increase weight. Blanket prohibition is incorrect because controlled use is permitted.

Question 13Fish Handling, Hygiene and Quality Control

A consignment of frozen fish shows a dry, whitish, porous surface after storage. Which phenomenon is this and what is its main cause?

  1. Rancidity caused by oxygen reacting with the skin
  2. Histamine formation caused by warm storage
  3. Freezer burn caused by moisture loss through sublimation from the surface Correct answer.
  4. Gaping caused by muscle contraction during rigor

Explanation

Freezer burn is the dry, whitish, porous appearance that results when surface moisture sublimes during frozen storage, especially with poor packaging or fluctuating temperatures. It is a quality defect rather than a direct safety hazard but reduces acceptability. Good wrapping and stable low temperatures prevent it.

Question 14Fish Handling, Hygiene and Quality Control

In the context of fish hygiene, which of the following best defines a critical control point in a HACCP plan?

  1. The final step where the product is packed for dispatch
  2. The step where the product is priced and labelled
  3. The step where workers take their scheduled break
  4. Any step where a hazard can be prevented, eliminated or reduced to an acceptable level Correct answer.

Explanation

A critical control point is a step in the process where control can be applied to prevent, eliminate or reduce a significant hazard to an acceptable level. It is identified from the hazard analysis and is monitored with defined limits. Packing, pricing and breaks are not defined by hazard control.

Question 15Fish Handling, Hygiene and Quality Control

A technician measures the temperature of a fish consignment and finds the core at 10 degrees Celsius while the surface is at 2 degrees Celsius. What is the most likely explanation?

  1. The fish was frozen and then thawed completely
  2. The fish was properly chilled throughout
  3. The fish had been heated to 70 degrees Celsius
  4. The fish was chilled only on the surface and the core remained warm Correct answer.

Explanation

A large gap between cold surface and warm core indicates that chilling has not penetrated the fish, which commonly occurs when fish are stacked thickly or chilled too slowly. Proper chilling should bring the core close to the surface temperature. Frozen-then-thawed fish would not show this pattern, and heating would raise both readings.

Question 16Fish Handling, Hygiene and Quality Control

Which of the following is the most appropriate reason for eviscerating fish promptly after capture?

  1. To increase the weight of the fish before sale
  2. To make the fish float higher in the hold
  3. To change the species classification of the catch
  4. To remove the gut enzymes and bacteria that accelerate belly-wall spoilage Correct answer.

Explanation

The gut and its contents carry high bacterial loads and proteolytic enzymes that diffuse into the belly wall and accelerate spoilage. Prompt evisceration, followed by thorough washing and chilling, markedly extends shelf life. It does not increase weight or affect species classification.

Question 17Fish Handling, Hygiene and Quality Control

A laboratory reports that a fish sample has a total volatile base nitrogen value well above the acceptable limit. What does this indicate?

  1. The fish has a high fat content
  2. The fish has undergone significant spoilage and is unsuitable for consumption Correct answer.
  3. The fish is of excellent freshness
  4. The fish has been irradiated to extend shelf life

Explanation

Total volatile base nitrogen is a chemical index of spoilage that measures volatile amines and ammonia produced by bacterial action. Values above the accepted limit indicate advanced spoilage and unsuitability for consumption. It is not a measure of fat content or an indicator of irradiation.

Question 18Fish Handling, Hygiene and Quality Control

Which practice best protects fish from contamination by handlers in a processing hall?

  1. Handling fish with bare hands after smoking outside
  2. Sharing aprons between shifts without washing
  3. Wearing jewellery to keep sleeves in place
  4. Wearing clean protective clothing and washing hands before handling fish Correct answer.

Explanation

Handlers are a major source of microbial contamination, so clean protective clothing, hand washing and good personal hygiene are essential. Jewellery can harbour bacteria and is generally prohibited. Sharing unwashed aprons and smoking before handling both increase contamination risk.

Question 19Fish Handling, Hygiene and Quality Control

Which of the following best explains why modified atmosphere packaging extends the shelf life of chilled fish fillets?

  1. It adds preservative chemicals directly into the flesh
  2. It raises the pH of the flesh to kill bacteria
  3. It replaces oxygen with gases such as carbon dioxide and nitrogen that inhibit spoilage organisms Correct answer.
  4. It freezes the product during storage

Explanation

Modified atmosphere packaging replaces the air around the product with a gas mixture, typically carbon dioxide and nitrogen, that suppresses the growth of aerobic spoilage bacteria and oxidative changes. It does not raise pH, freeze the product or add chemicals to the flesh. The product must still be kept chilled.

Question 20Fish Handling, Hygiene and Quality Control

A fish sample is tested and shows a high count of Escherichia coli. What is the most appropriate interpretation?

  1. This indicates the fish is rich in nutrients
  2. This indicates faecal contamination and poor hygiene during handling or washing Correct answer.
  3. This is normal for all fresh fish and requires no action
  4. This confirms the fish was properly iced

Explanation

Escherichia coli is a faecal indicator organism, so its presence in significant numbers signals faecal contamination and failures in hygiene, water quality or handling. It is not a normal component of fresh fish flora and does not indicate nutritional value or good icing. Corrective action should address sanitation and water sources.

Question 21Fish Handling, Hygiene and Quality Control

Which of the following statements about the relationship between storage temperature and fish shelf life is most accurate?

  1. Shelf life depends only on the species and not on temperature
  2. Shelf life is independent of storage temperature
  3. Shelf life generally decreases as storage temperature rises within the chilled range Correct answer.
  4. Shelf life increases as storage temperature rises within the chilled range

Explanation

Within the chilled range, the growth rate of spoilage bacteria and the rate of autolytic reactions increase with temperature, so shelf life generally shortens as storage temperature rises. This is why maintaining fish near 0 degrees Celsius in melting ice is so important. Species and other factors also matter, but temperature is a dominant variable.

Question 22Fish Handling, Hygiene and Quality Control

A processor wants to reduce the risk of Listeria monocytogenes in a cold-smoked fish operation. Which combination of measures is most appropriate?

  1. Packaging the product in open trays without chilling
  2. Maintaining strict cold-chain control, sanitation of contact surfaces and environmental monitoring Correct answer.
  3. Reducing the salt content of the product to zero
  4. Increasing storage temperature to encourage competing flora

Explanation

Listeria monocytogenes can grow at refrigeration temperatures and persists in processing environments, so control relies on strict cold chain, effective sanitation of contact surfaces and environmental monitoring for the organism. Raising temperature, removing salt and leaving product unchilled would all increase risk.

Question 23Fish Handling, Hygiene and Quality Control

During a quality audit, a plant reports that its ice-making water has a high coliform count but its fish storage temperature records are satisfactory. What is the most defensible conclusion?

  1. The fish must be rejected because temperature records are unsatisfactory
  2. The fish is safe because temperature records are satisfactory
  3. The ice is a potential contamination source and the water treatment must be corrected Correct answer.
  4. The coliform count is irrelevant because ice is frozen

Explanation

Ice made from coliform-contaminated water can inoculate bacteria directly onto fish, so satisfactory temperature records alone do not guarantee hygienic quality. The water treatment and ice-making process must be corrected, and the affected ice should not be used until verified. Frozen state does not eliminate coliforms, and the temperature records are reported as satisfactory.

Question 24Fish Handling, Hygiene and Quality Control

A batch of scombroid fish is suspected of causing illness in consumers. Which set of circumstances most plausibly explains the outbreak?

  1. The fish was frozen at -30 degrees Celsius immediately after capture
  2. The fish was held at warm ambient temperatures for several hours before icing Correct answer.
  3. The fish was cooked to an internal temperature above 70 degrees Celsius
  4. The fish was eviscerated and iced within minutes of capture

Explanation

Histamine forms when scombroid fish are held at warm temperatures, allowing bacteria to decarboxylate histidine into histamine. Prompt deep freezing, rapid evisceration with icing and thorough cooking do not create the conditions for histamine accumulation, and cooking does not destroy histamine already formed. The warm holding period is therefore the plausible cause.

Question 25Fish Handling, Hygiene and Quality Control

A plant uses a chlorinated wash for equipment but a worker also sprays the same solution directly onto exposed fillets to save time. Why is this practice unacceptable?

  1. It reduces the weight of the fillet and is uneconomical
  2. It risks chemical contamination of the edible product and breaches approved sanitation practice Correct answer.
  3. It improves shelf life and is therefore acceptable
  4. It makes the fillet too cold for packaging

Explanation

Sanitisers are approved for food-contact surfaces and equipment at specified concentrations, not for direct application to edible fish flesh, where they can leave chemical residues and exceed permitted limits. The correct practice is to sanitise surfaces and rinse as specified, keeping chemicals away from the product. This is a hygiene and regulatory breach, not a shelf-life benefit.

Question 26Fish Handling, Hygiene and Quality Control

Which sensory change is the earliest reliable indicator that chilled whole fish is losing freshness?

  1. Bright red gills with a clean seaweedy odour
  2. Clear, convex eyes with a translucent cornea
  3. Sunken, cloudy eyes with a dull grey cornea Correct answer.
  4. Firm, elastic flesh that springs back when pressed

Explanation

In fresh fish the eyes are convex, clear and bulging, and the gills are bright red with a fresh seaweedy smell. As autolysis and bacterial spoilage advance, the eye collapses and the cornea becomes cloudy and grey, which is one of the first changes a trained grader records. Firm elastic flesh and bright gills describe fresh, acceptable fish rather than deterioration.

Question 27Fish Handling, Hygiene and Quality Control

A landing centre receives fish in open baskets stacked on a wet concrete floor. Which handling change most directly reduces the risk of recontamination of the fish?

  1. Extending the time the fish waits before icing to allow draining
  2. Raising the baskets on clean pallets and keeping them off the floor Correct answer.
  3. Washing the concrete floor with the same water used for the fish
  4. Adding more ice to the top of each basket only

Explanation

Floors carry soil, wash water and spilled fish liquor, so containers placed directly on them pick up contamination and transfer it to the fish. Elevating the baskets on clean, washable pallets breaks that route and also improves air circulation and drainage. The other measures either do not interrupt the floor-to-fish contact or add new contamination risks.

Question 28Fish Handling, Hygiene and Quality Control

A plant records that its potable water supply is chlorinated to 0.5 mg per litre free residual chlorine at the point of use. Which statement best explains the quality-control purpose of maintaining this residual?

  1. It provides a measurable disinfection safeguard against bacterial contamination in the water up to the point of use Correct answer.
  2. It acts as a preservative that extends the shelf life of fish stored in that water
  3. It removes dissolved proteins and fats from water used for washing fish fillets
  4. It raises the water temperature sufficiently to destroy spoilage bacteria on contact

Explanation

A free chlorine residual shows that the water still holds disinfecting capacity after travelling through the distribution system, so it protects against bacterial contamination that may enter downstream of treatment. It is monitored as a verification step for potable water quality. Chlorine does not remove organic matter, does not heat water, and is not a preservative for the fish itself.

Question 29Fish Handling, Hygiene and Quality Control

A processing line uses a metal detector on packed fillets, and the unit is checked only at the start of each shift. Which change makes this control more effective as part of the plant's food safety system?

  1. Testing the detector with ferrous, non-ferrous and stainless steel reference pieces at defined intervals and recording the results Correct answer.
  2. Increasing the conveyor speed so that more packs pass the detector each hour
  3. Replacing the detector check with a visual inspection of each fillet by the operator
  4. Testing the detector only when a customer complains about foreign matter

Explanation

A metal detector is a control measure whose performance must be verified, so it is challenged with test pieces representing the likely contaminants at planned intervals and the outcome is documented. This detects drift or failure before large amounts of product pass unchecked. Faster belts, visual inspection alone and complaint-driven testing all weaken assurance.

Question 30Fish Handling, Hygiene and Quality Control

Two consignments of the same species are landed together: one is gutted and iced within one hour of capture, the other is kept whole on deck without ice for five hours and then iced. Both are stored identically afterwards. Which explanation best accounts for the difference in their expected shelf life?

  1. Icing the second consignment later simply delays cooling and has no lasting effect on spoilage once both reach the same temperature
  2. Delayed chilling allows gut enzymes and bacteria to act during the warm period, so spoilage starts from a higher baseline that later icing cannot reverse Correct answer.
  3. Shelf life depends only on the storage temperature after landing, so both consignments will spoil on the same day
  4. Whole ungutted fish always keep longer than gutted fish because the viscera protect the flesh from bacterial attack

Explanation

Spoilage is cumulative, and the rate of bacterial growth and enzymatic breakdown rises steeply at warm temperatures. Five hours on deck without ice lets visceral enzymes and bacteria make substantial progress, so the second lot enters chilled storage with a higher microbial load and advanced autolysis. Later icing slows further change but cannot undo the earlier damage, which is why prompt chilling and evisceration are core handling rules.

Question 31Fish Processing Technology

In fish processing, the term 'rigor mortis' refers to which post-mortem change?

  1. The stiffening of muscle caused by depletion of ATP and formation of actomyosin Correct answer.
  2. The loss of water-holding capacity due to freezing
  3. The softening of muscle due to proteolytic breakdown of collagen
  4. The development of off-odours due to bacterial action

Explanation

Rigor mortis is the stiffening of fish muscle after death. It occurs when ATP levels fall, allowing myosin and actin to bind irreversibly as actomyosin, making the muscle rigid until proteolysis and pH changes resolve it.

Question 32Fish Processing Technology

Which of the following is the primary reason for gutting fish soon after catch in fish processing?

  1. To enhance the natural colour of the flesh
  2. To improve the appearance of the fish for retail display
  3. To increase the weight of the fish by removing water
  4. To remove viscera that are a major source of enzymes and bacteria causing spoilage Correct answer.

Explanation

The visceral organs contain high levels of digestive enzymes and bacteria. Removing them promptly reduces enzymatic autolysis and microbial growth, thereby extending shelf life and maintaining quality.

Question 33Fish Processing Technology

In fish canning, the purpose of the 'exhausting' step before sealing is to:

  1. Add steam to improve flavour
  2. Sterilise the product before retorting
  3. Increase the internal pressure to prevent seam failure
  4. Remove air from the can to create a vacuum and reduce oxidative changes Correct answer.

Explanation

Exhausting removes air from the headspace and product, creating a vacuum after sealing. This reduces oxidative rancidity, prevents can distortion during retorting, and limits corrosion of the can.

Question 34Fish Processing Technology

Which of the following fish species is commonly used for the production of 'surimi'?

  1. Alaska pollock Correct answer.
  2. Mackerel
  3. Tuna
  4. Sardine

Explanation

Alaska pollock (Theragra chalcogramma) is the principal species used for surimi because its flesh forms a strong gel and has a mild flavour. Other species like mackerel and sardine are oily and less suitable for high-quality surimi.

Question 35Fish Processing Technology

The water activity (aw) of fresh fish muscle is approximately:

  1. 0.70
  2. 0.80
  3. 0.99 Correct answer.
  4. 0.90

Explanation

Fresh fish muscle has a high water activity, typically around 0.99, which supports the growth of most spoilage bacteria. Reducing aw below 0.90 is a preservation principle in drying and salting.

Question 36Fish Processing Technology

In fish processing, 'drip loss' refers to:

  1. The loss of moisture during drying
  2. The loss of nutrients during canning
  3. The loss of water and soluble components from muscle during thawing or storage Correct answer.
  4. The loss of oil during frying

Explanation

Drip loss is the exudate released from fish muscle when it is thawed or stored, consisting of water and soluble proteins. It affects yield, texture, and nutritional quality.

Question 37Fish Processing Technology

Which of the following is a typical sign of spoilage in fresh fish?

  1. Firm flesh that springs back when pressed
  2. Neutral odour
  3. Sunken eyes and greyish-brown gills Correct answer.
  4. Bright red gills and clear eyes

Explanation

Spoilage is indicated by sunken, cloudy eyes and greyish-brown gills with a foul odour. Fresh fish has bright red gills, clear eyes, and firm flesh.

Question 38Fish Processing Technology

The main preservative effect of salting fish is due to:

  1. Addition of nutrients
  2. Reduction of water activity Correct answer.
  3. Removal of oxygen
  4. Increase in pH

Explanation

Salt reduces water activity by binding water, creating an environment unsuitable for many spoilage microorganisms. This is the primary preservation mechanism in salted fish products.

Question 39Fish Processing Technology

In fish freezing, the 'latent heat of fusion' must be removed to convert water to ice. For fish muscle, this is approximately:

  1. 500 kJ/kg
  2. 334 kJ/kg Correct answer.
  3. 100 kJ/kg
  4. 50 kJ/kg

Explanation

The latent heat of fusion of water is about 334 kJ/kg, which is the energy that must be removed to freeze water in fish muscle. This value dominates the refrigeration load during freezing.

Question 40Fish Processing Technology

Which of the following is a characteristic of 'cold smoking' compared with 'hot smoking'?

  1. Cold smoking requires no curing salt
  2. Cold smoking produces a drier product due to higher heat
  3. Cold smoking uses higher temperatures and cooks the fish
  4. Cold smoking is carried out at lower temperatures and does not cook the fish Correct answer.

Explanation

Cold smoking typically occurs at temperatures below 30°C, preserving the fish without cooking it, while hot smoking uses temperatures above 70°C, which coagulates proteins and cooks the product.

Question 41Fish Processing Technology

In the production of fish meal, the 'wet rendering' process involves:

  1. Cooking, pressing, drying, and grinding Correct answer.
  2. Freezing, thawing, and grinding
  3. Fermenting and sun-drying
  4. Salting, drying, and smoking

Explanation

Wet rendering is the standard fish meal process: cooking coagulates proteins, pressing removes oil and water, drying reduces moisture, and grinding produces meal. This sequence is essential for stable, high-protein meal.

Question 42Fish Processing Technology

Which of the following is a critical control point (CCP) in a fish canning operation?

  1. Packaging material storage
  2. Retort processing time and temperature Correct answer.
  3. Labeling of cans
  4. Receiving of fresh fish

Explanation

Retort processing is a CCP because it is the step that ensures commercial sterility by destroying Clostridium botulinum spores. Failure to control time and temperature can lead to serious food safety hazards.

Question 43Fish Processing Technology

The presence of 'black spot' in canned fish is usually caused by:

  1. Growth of black mould on the fish
  2. Oxidation of fish oil
  3. Iron sulphide formation from reaction of hydrogen sulphide with iron in the can Correct answer.
  4. Caramelisation of sugars

Explanation

Black spot in canned fish is due to iron sulphide, formed when hydrogen sulphide from protein breakdown reacts with iron exposed in the can. It is a cosmetic defect but indicates improper lacquering or high sulphur content.

Question 44Fish Processing Technology

In fish processing, 'glazing' refers to:

  1. Applying a thin ice glaze to frozen fish to prevent dehydration Correct answer.
  2. Coating fish with sugar syrup
  3. Adding a glaze of oil before smoking
  4. Dipping fish in brine before drying

Explanation

Glazing involves dipping frozen fish in water or spraying it to form a protective ice layer. This glaze prevents freezer burn and dehydration by limiting moisture loss and oxygen contact.

Question 45Fish Processing Technology

Which of the following is the most appropriate method to control histamine formation in fish?

  1. Adding antioxidants
  2. Immediate chilling to near 0°C after catch Correct answer.
  3. Salting at 10% NaCl
  4. Vacuum packaging at ambient temperature

Explanation

Histamine is produced by bacterial decarboxylation of histidine, which is rapid at warm temperatures. Immediate chilling to near 0°C slows bacterial growth and prevents histamine formation.

Question 46Fish Processing Technology

The principle of 'Hurdle Technology' in fish preservation involves:

  1. Adding chemical preservatives only
  2. Relying solely on refrigeration
  3. Combining multiple mild preservation factors to inhibit spoilage Correct answer.
  4. Using a single severe treatment to ensure safety

Explanation

Hurdle technology combines several mild preservation hurdles (e.g., low temperature, reduced aw, pH, preservatives) that together inhibit microbial growth and improve product stability without harsh single treatments.

Question 47Fish Processing Technology

In the context of fish drying, 'case hardening' refers to:

  1. The development of a tough texture due to collagen cross-linking
  2. The hardening of fish bones during drying
  3. The increase in protein content due to moisture loss
  4. The formation of a hard impermeable surface layer that traps moisture inside Correct answer.

Explanation

Case hardening occurs when the surface of the fish dries too quickly, forming a hard crust that prevents internal moisture from escaping. This leads to uneven drying and potential spoilage.

Question 48Fish Processing Technology

Which of the following statements about the freezing curve of fish is correct?

  1. Fish muscle freezes at exactly 0°C
  2. The freezing point of fish muscle is lower than that of pure water due to dissolved solutes Correct answer.
  3. The freezing point is unaffected by the presence of salts
  4. The freezing point increases with solute concentration

Explanation

Dissolved salts and organic compounds in fish muscle depress the freezing point below 0°C, typically to about -1 to -2°C. This colligative property is important in designing freezing processes.

Question 49Fish Processing Technology

In fish processing, the term 'autolysis' refers to:

  1. Loss of water from fish muscle
  2. Breakdown of fish tissue by its own enzymes Correct answer.
  3. Breakdown of fish tissue by bacteria
  4. Oxidation of fish lipids

Explanation

Autolysis is enzymatic self-digestion of fish tissue by endogenous enzymes such as proteases and lipases. It leads to softening and changes in flavour and texture even before bacterial spoilage dominates.

Question 50Fish Processing Technology

A fish processor wants to produce salted dried mackerel with a water activity of 0.85. Which combination of hurdles would be most effective?

  1. Addition of water and refrigeration
  2. Increased salt content and adequate drying Correct answer.
  3. Reduced salt content and vacuum packaging
  4. Use of antioxidants and high temperature

Explanation

To achieve aw 0.85, both salting and drying are needed because salt alone or drying alone may not reach that level uniformly. The combined hurdles reduce water activity and inhibit microbial growth.