Shellfish Safety and Cooking Methods Quiz

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the minimum cooking temperature and time required to effectively kill norovirus in oysters?

70°C for 60 seconds

80°C for 30 seconds

100°C for 120 seconds

90°C for 90 seconds (correct)

Which of the following is NOT a suggested cooking method for oysters?

Frying for at least 3 minutes at 160°C (correct)

Boiling until shells open, then for an additional 3-5 minutes

Baking for at least 10 minutes at 230°C

Steaming for 4-9 minutes, discarding unopened shells

What process do microorganisms use to convert carbohydrates into alcohol and/or acid during fermentation?

Oxidation

Reduction

Metabolism (correct)

Hydrolysis

Which grading system is used for Pacific Salmon?

Grade A, Standard, Utility Signup and view all the answers

Which of the following fermented products is made through the action of microorganisms?

Fermented sausage Signup and view all the answers

What is the primary goal of the Canadian Shellfish Sanitation Program?

To protect Canadians from contaminated shellfish Signup and view all the answers

What is one of the roles of the Canadian Food Inspection Agency (CFIA) in the CSSP?

Regulating import and export of shellfish Signup and view all the answers

In anaerobic conditions during fermentation, what must part of the sugar serve as?

An electron acceptor Signup and view all the answers

What does the Department of Fisheries and Oceans Canada (DFO) primarily control in relation to shellfish?

Harvesting and restricting from contaminated areas Signup and view all the answers

What factor can lead to emergency closures of shellfish harvesting areas?

Heavy rainfall or oil spills Signup and view all the answers

What should be the maximum time between harvest and depuration of shellfish?

3 days Signup and view all the answers

During the depuration process, what must the water contain?

300 fish Signup and view all the answers

What is one of the activities included in the shellfish sanitation program?

Harvesting, handling, and storage of shellstock Signup and view all the answers

What is the main reason for spoilage in soft, unripened cheeses?

Oxygen exposure leading to mould growth Signup and view all the answers

Which bacteria are commonly associated with spoilage in butter?

Pseudomonas spp. Signup and view all the answers

What recommendation is made for high-risk groups regarding cheese consumption?

Avoid consumption of all soft cheeses Signup and view all the answers

Which of the following factors contributes to food-borne illness outbreaks from soft cheeses made from unpasteurized milk?

Contaminated milk and environment Signup and view all the answers

What role does salt play in the fermentation of sauerkraut?

Inhibits Gram-negative bacteria, allowing fermentation Signup and view all the answers

What is the key toxin produced by the dinoflagellate Gambierdiscus toxicus responsible for ciguatera poisoning?

Ciguatoxin Signup and view all the answers

Which of the following symptoms is commonly associated with ciguatera poisoning?

Nausea and vomiting Signup and view all the answers

What condition is caused by saxitoxins from dinoflagellates of the Alexandrium and Gymnodinium genera?

Paralytic shellfish poisoning Signup and view all the answers

What is the typical timeframe for symptoms to develop in Amnesic Shellfish Poisoning?

Within 24-48 hours Signup and view all the answers

Which toxin is associated with Diarrhetic Shellfish Poisoning (DSP)?

Okadaic acid Signup and view all the answers

Which condition's symptoms include tingling, burning, and numbness within 2 hours?

Paralytic shellfish poisoning Signup and view all the answers

What are common causes of food-borne disease outbreaks linked to raw oysters?

Norovirus and Vibrio spp. Signup and view all the answers

Which of the following neurotoxic symptoms is typical for Neurotoxic Shellfish Poisoning (NSP)?

Temperature reversal Signup and view all the answers

What is the ideal final pH for sauerkraut to ensure it is safe to eat?

3.1 to 3.7 Signup and view all the answers

Which of the following materials should be avoided when fermenting food?

Old ceramic crocks Signup and view all the answers

What is a primary cause of spoilage in sauerkraut that can lead to bacterial growth?

All of the above Signup and view all the answers

During pickle fermentation, what concentration of salt is typically used in commercial processes?

6% for 6-9 weeks Signup and view all the answers

What undesirable condition may develop in pickles if there is excessive carbon dioxide or bacterial growth?

Bloaters Signup and view all the answers

Which type of spoilage in sauerkraut is indicated by a soft texture and undesirable smell?

Bacterial spoilage Signup and view all the answers

What is the function of salt during the fermentation of cucumbers into pickles?

To extract water and other compounds Signup and view all the answers

What could indicate that surface spoilage is happening in sauerkraut?

Mould growth on the surface Signup and view all the answers

What is the primary purpose of forming organic acids during fermentation?

To restrict pathogen growth Signup and view all the answers

At what temperature is the ideal fermentation of tempeh achieved?

31°C Signup and view all the answers

Which ingredient is NOT typically used in kimchi preparation?

Chopped carrots Signup and view all the answers

What is a unique characteristic of kombucha as compared to other fermented products mentioned?

It is a beverage made from brewed tea. Signup and view all the answers

What does the fermentation of tempeh primarily increase in the product?

Vitamin content Signup and view all the answers

What should be done to napa cabbage before mixing in the seasonings for kimchi?

It should be salted. Signup and view all the answers

What is a pivotal factor for the fermentation time of kimchi at room temperature?

Room temperature Signup and view all the answers

What is a potential risk associated with tempeh production?

Contaminated starter culture Signup and view all the answers

Study Notes

Seafood & Fermented Foods

Seafood encompasses fish, crustaceans, and mollusks from marine and freshwater waters.
It's one of the most perishable protein-based foods, often linked to foodborne illnesses.
Healthy fish's microbiota reflects its source water.
Pre-harvest, fish inner tissues are sterile.
Shellfish can be contaminated during harvest from fecal pollution or natural biota.
Post-harvest contamination occurs through processing/handling.

Seafood Microbiota

Microbiota exists on outer slime, gills, and intestines, including bacteria (e.g., Aeromonas, Pseudomonas, Shewanella, Moraxella, Vibrio), yeasts (e.g., Candida, Cryptococcus, Rhodotorula, Sporobolomyces), and molds (e.g., Aspergillus, Aureobasidium, Penicillium).

Seafood Spoilage

Fresh fish spoilage is mainly due to Gram-negative, non-spore formers.
Spoilage of freshwater and saltwater fish occurs similarly.
The gills are the most susceptible part, showing spoilage signs early.
Trimethylamine-N-oxide (TMAO) is a natural fish component.
Microbial action converts TMAO to trimethylamine (TMA), causing the characteristic fishy odor of spoiled fish.
TMA is used for detecting spoilage.
Other spoilage metabolites include CO2, ethanol, propanol, isopropanol, histamine, and volatile organic acids/total volatile nitrogen.
Unsaturated oils in fish are prone to oxidation (rancidity).

Seafood Spoilage Detection

Freshly caught fish have little odor.
Odor development varies by species and time, primarily from TMA and rancid oils.
Surface slime: Normal is thin, clear, and slippery; deterioration thickens, discolors, and develops objectionable odors.
Sticky/tacky flesh indicates spoilage.
Fresh fish flesh is springy but softens with spoilage.

Seafood Spoilage (Additional factors)

Eyes: Fresh eyes are bright and convex; stale eyes are dull and collapsed.
Blood: Fresh blood is bright red; stale blood darkens in gills and along the spine.
Color: Fresh fish have bright colors that fade and show yellow, green, or brown discoloration with spoilage.
Crustaceans: Include shrimp, lobsters, crabs, and crayfish; susceptible to similar spoilage organisms as fish.
- They are often sold alive in tanks and should be inspected for dead animals—these should be removed to prevent contamination.
Mollusks: Include oysters, clams, mussels, and scallops; spoilage is tracked by pH decrease.
- 5.9–6.2 pH is good; 5.8 is "off"; 5.5–5.7 is "musty"; and any lower is sour/putrid.
- Mollusks are filter feeders and can concentrate pathogens from contaminated water.

Seafood Inspections

Fresh whole fish: Fresh, mild odor; firm flesh.
Fresh whole shellfish: Fresh, mild odor; tightly closed shells.
Fresh fillets: Glossy, firm/elastic flesh; no discoloration; well-iced.

Seafood Legislation: Federal

Federal regulations cover fish and seafood processing within establishments and imports into Canada.
It includes licensing of establishments, grading requirements (e.g., Pacific Salmon grades), labeling and packing, general food safety provisions (including preventive control plans), and import restrictions.

Canadian Shellfish Sanitation Program (CSSP)

CSSP is a federal food safety program concerning contaminated bivalve molluscan shellfish.
It's administered by CFIA, Environment Canada, and Fisheries and Oceans Canada.
CFIA regulates imports/exports/processing, inspects for certification, and maintains biotoxin surveillance in shellfish growing areas.
Environment Canada monitors water quality.
Fisheries & Oceans Canada controls harvesting and prevents harvesting from contaminated areas.
The CSSP covers shellfish area surveys, harvesting control, handling/storage, shucking, and packing shellfish.
It includes decontamination policies in case of contaminated areas by operators.
Significant weather events/unexpected events (e.g., oil spills) can result in harvesting area closures.

CFIA Depuration Requirements

Time between harvest and depuration should be 3 days maximum.
Shellfish are washed and culled before depuration to remove damaged/dead ones.
Water quality must have <2 total coliforms/100 mL.
Other parameters should be met (e.g., salinity), potentially involving UV treatment.
Tanks must meet a 4:1 water to shellfish volume ratio (soft clams) and a 6.4:1 ratio (other shellfish).
Post-depuration, shellfish must be refrigerated at 4°C or below.
Sample lots are tested for fecal coliforms at depuration's start and end.

Seafood Legislation: Provincial

In Ontario, OMAFRA handles fish inspection, including the Fish Inspection Act and Quality Control Regulation.
This includes auditing ~100 non-federally registered fish processors and bacterial sampling at ready-to-eat facilities.
Audits are done three times a year, with food safety training and best practices provided to operators.
Fish processors in Ontario do not require OMAFRA licenses.
OMAFRA is proposing new fish regulations under the Food Safety and Quality Act to provide licensing and inspection powers similar to other commodities (e.g., meat and dairy).
A 2018-2019 Auditor General analysis showed two-thirds of infractions were repeat offenses.
Issues include non-potable water, inadequate staff training, and lack of temperature verification during fish smoking procedures.
High bacterial counts were also found on food contact surfaces and equipment (20% of tests).

Food Premises: Raw Fish

To kill parasites in raw fish (e.g., sushi), freezing at -20°C for 7 days or -35°C for 15 hours before preparation/serving is recommended, as directed by MOHLTC.
Vulnerable populations (elderly, pregnant, immunocompromised) should avoid raw fish consumption.
MOHLTC considers sushi rice non-hazardous at room temperature if a vinegar solution reduces pH to ≤4.2.
Raw fish should be consumed daily and not stored from previous days preparation.

Seafood Poisoning (Types)

Scombroid poisoning: Microbial conversion of histidine to histamine in fish (tuna, mackerel, bonito). Symptoms (flushing, rash, discomfort, headache, itching, etc.) appear within minutes and typically last up to 3 hours. Cooking does not destroy histamine.
Ciguatera poisoning (CFP): Toxins (CTX) from algae travel up the food chain to fish. Consumption of contaminated fish causes CFP in humans.
Shellfish Poisoning: These arise from plankton algae (dinoflagellates, diatoms).
Paralytic Shellfish Poisoning (PSP): Saxitoxins produced by Alexandrium and Gymnodinium, neurological symptoms (tingling, burning, numbness) develop within 2 hours., potentially severe.
Amnesic Shellfish Poisoning (ASP): Domoic acid from Nitzchia pungens, causes gastroenteric/neurologic symptoms within 24-48 hours, potentially severe in elderly.
Diarrhetic Shellfish Poisoning (DSP): Toxins (polyether molecules, e.g., okadaic acid) produced by dinoflagellates, mild GI distress (nausea, vomiting, abdominal cramps, diarrhea, chills), 30 min to 3 hours after ingestion.
Norovirus: Raw oysters can be a source.

Fermented Food Products

Fermented foods involve chemical changes due to microorganisms.
Microorganisms often convert carbohydrates (e.g., starch, sugar) into alcohol or acids, with interest renewed for preserving food, extending shelf life, creating flavors/textures, and health benefits.
Examples include salami, cheese, yogurt, sauerkraut, kimchi, pickles, olives, kombucha, tempeh, miso, beer, wine, and bread.

Biochemical Foundation (Fermentation)

Oxidation involves an electron loss, transferred to an acceptor.
Complete sugar oxidation yields energy stored as ATP.
Food fermentation occurs under anaerobic conditions.
Incomplete oxidation produces byproducts such as ethanol, acetic acid, lactic acid, that can be further oxidized by microorganisms.
Simplified metabolic pathways in fermented foods shown via the Embden-Meyerhof-Parnas and Entner-Doudoroff pathways.

Fermented Meat Products

Meat's natural microbiota is gram-negative and aerobic.
Fermentation with LAB (lactic acid bacteria) prevents spoilage and changes the meat.
Some producers still utilize naturally occurring microbiota, while others use starter cultures of LAB or staphylococci.
Starter cultures are specifically selected for their metabolic activities in meat systems.
Starter cultures are beneficial for consistency and accelerating processing time.
Common examples are dry and semi-dry sausages.

Fermented Sausages (Manufacture)

Dry and semi-dry sausage production reduces meat particles by grinding, adds salt, nitrate/nitrite, glucose, spices, and starter cultures (107 CFU/g).
Ingredients are blended, vacuum packed, incubated to reduce pH, heated to inactivate cultures, and aged.
Nitrate/nitrite inhibits C. botulinum, cures taste, and changes myoglobin to nitrosomyoglobin.

Fermented Sausages (Examples)

Detailed description and unique features for different types of dry and semi-dry sausages (e.g., salami, mortadella, pepperoni, chorizo, summer sausages/cervelat, teewurst, mettwurst, Lebanon bologna).

Fermented Sausages: Safety

Fermented sausages are traditionally safe due to low aw and pH.
Concerns are mainly about E. coli O157:H7 due to low infectious dose and rapid survival/growth in such products, needing high standards for fermentation and temperature/processing.
CFIA requirements for "shelf-stable" fermented sausages include minimum nitrate/nitrite, salt, and specified fermentation time/temperature protocols to achieve final pH ≤4.6/aw ≤0.85, or pH ≤5.3 if aw ≤ 0.90 and for heat treatment or other process validation.

Federal Regulations

Registered federally inspected establishments need to have fermentation time/temperature control programs to control pathogens.
Those using beef must implement one of five options for E. coli O157:H7 and Salmonella control: heat treatment; a validated manufacturing process; testing, holding; microbiological testing validated for 2D or 5D reduction; and validation challenge studies with 5D reductions.

Provincial Regulations

Fermenting is a high-risk (Category 2) activity regulated under the provincial Meat Regulation.
Requires a license under the Food Safety and Quality Act.
Provincial staff conduct inspections and have a microbiological monitoring program for meat plants that produce ready-to-eat meat products.

Fermented Dairy Products

Various dairy products (e.g., butter, buttermilk, yogurt).
Fermentation by lactic acid bacteria (LAB).
Pasteurization reduces natural LAB, requiring starter cultures (e.g., Lactococcus lactis subsp. cremoris/lactis).
Other bacteria (secondary microbiota) influence flavor and texture (e.g., Leuconostoc species).

Butter & Yogurt

Butter and Buttermilk: LAB culture is added to pasteurized cream, maintained until desired acidity is reached, and churned to separate solids and buttermilk.
Yogurt: Milk is first heated to reduce water; Lactobacillus bulgaricus and Streptococcus thermophilus are added in a 1:1 ratio (2% by volume); probiotic yogurts may also include Bifidobacterium or L. acidophilus; coccus (faster) produces acid, while bacillus produces flavors (acetyldehyde); high LAB counts (109 cfu/g) present.

Cheese

Cheese production is a multi-step process:
1. Standardizing milk (protein/fat ratio) for quality/yield.
2. Pasteurization to kill spoilage organisms and improve environment for starter cultures.
3. Raising milk temperature to 30-32°C for optimal starter activity.
4. Adding starter cultures and ripening (by LAB or molds/brie/cottage cheese).
5. Adding rennet enzyme to coagulate milk proteins and form curds.
6. Fermenting curds, cutting/heating, separating whey, salting, and pressing into blocks.
7. Additional ingredients and aging (for weeks/years).

Dairy Product Spoilage

Butter: Spoilage includes molds and yeasts that cause discolorations, surface taints, rancidity, and skunk-like odors (due to Pseudomonas spp.).
Cottage Cheese: Spoilage can be bacteria or molds/yeasts causing slimy curd, or stale, musty, moldy, or yeasty flavors.
Soft cheeses are more susceptible to mold growth when oxygen is present, usually caused by Penicillium spp.
Hard/semi-hard cheeses are less susceptible due to low moisture.

Cheese Food Safety Concerns

Soft cheeses and those from unpasteurized milk are prone to Salmonella and Campylobacter outbreaks.
Main factors are contamination from animals or environment, as well as inadequate time/temperature control
Pasteurized cheeses can also cause outbreaks, mostly due to Listeria or norovirus due to improper cleaning, storage, food handling, and worker hygiene.
Health Canada recommends limiting high-risk group consumption of soft cheeses.

Sauerkraut

Sauerkraut is fermented cabbage, utilizing its natural microbiota (lactic acid bacteria).
Salt addition (2–2.5%) inhibits negative bacteria.
A suitable vessel (glass, food-grade plastic, ceramic) and covering is needed for anaerobic fermentation.
Fermentation time is 3–4 weeks (21–24°C), longer at lower temperatures, which must not be below 15°C.
Final pH is 3.1–3.7 (acidity 1.6–1.8%).

Sauerkraut Spoilage

Spoilage is indicated by undesirable color, off-odors, and soft texture, potentially making it unsafe if insufficient acid production during fermentation occurs.
Spoilage may be due to surface mold growth, softness (low salt/high temp/uneven salt distribution/air pockets), and rotten/pink kraut (mold/yeast growth).

Pickles

Pickles are fermented cucumbers, using natural lactobacillus bacteria.
Commercial processing places cucumbers in high salt brine tanks (6% for 6-9 weeks).
Salt prevents negative bacteria, drawing out water/sugars to produce lactic acid (final pH ≈ 3.7-4.0).
Home fermentation methods are similar to sauerkraut preparation.
Spoilage factors include: excessive carbon dioxide or bacterial growth resulting in "bloaters" (gas pockets).
Additional spoilage factors include blackening and softening due to bacteria or microbes.

Kimchi

Kimchi is a traditional Korean dish made from fermented cabbage or radish, utilizing a mixture of seasonings (e.g., green onions, ginger, garlic, red pepper).
Organic acids (primarily lactic and acetic acid) form, lowering pH to 4.2, restricting pathogen growth.
Fermentation at room temperature usually takes 1-2 days or slower in the refrigerator.
Kimchi is best eaten within 1 week; refrigeration may be necessary depending on pH.

Tempeh

Tempeh is a fermented soybean product.
It has a chewy texture and earthy flavor, becoming a higher-protein, dietary-fiber, and vitamin-rich meat alternative.
Fermentation uses Rhizopus mold to bind soybeans while fermenting in enclosed container for 20–28 hours at 31°C

Kombucha

Kombucha is a fermented beverage made from brewed tea and sugar.
It has a slightly sweet and acidic taste with residual carbon dioxide.
It's consumed in many countries; growing in popularity in North America as a healthy beverage.
The fermentation process is similar to vinegar, using a "symbiotic culture of yeasts and bacteria" (SCOBY) that ferments at room temperature for 7–10 days.
The final pH should be 2.5–4.2 and have alcohol/acetic acid content <1%.

Fermented Nut Cheese

Fermented plant-based nut cheeses are becoming popular.
Outbreaks from Salmonella are linked to high-risk production practices, using "rejuvulac" (i.e., sprouted seed water) which is not recommended. Laboratory-verified LAB cultures should be used instead.
Nuts should be pasteurized in a water bath ≥90°C for ≥2 minutes prior to fermentation.
Room-temperature fermentation (24–48 hours) reduces pH to ≤4.4.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Test your knowledge on shellfish safety, cooking methods, and the role of various Canadian agencies in shellfish sanitation. This quiz covers topics such as norovirus, fermentation processes, and regulations concerning Pacific Salmon. Perfect for food safety students and seafood industry professionals.