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Retail Seafood Cross-Contamination
Cross-Contamination
Cross-contamination is the transfer of illness-causing bacteria and viruses
to cooked "ready-to-eat" seafoods. These seafoods include cooked crabmeat,
cooked shrimp, smoked seafoods, and surimi-based simulated seafood products.
Cross-contamination can occur from:
- Raw seafood to cooked seafood
- Equipment or utensils to cooked seafood
- Seafood handlers to cooked seafood
- The environment to cooked seafood
Illness Causing Bacteria and Viruses
Seafoods, like other foods, may contain illness-causing bacteria and
viruses. These microorganisms come from the marine environ ment, water
pollution, or contamination (see table on page 2). Contamination may be from
seafood handlers, equipment or the environment.
Illness-causing bacteria and viruses are usually not a problem in raw seafoods.
Normal cooking to an internal temperature of 140°F kills them. Bacteria and
viruses can cause illness when they are present in seafoods consumed without
cooking, or in cooked seafoods. Prevent cross-contamination through good
sanitation, personal hygiene, and seafood handling practices.
Raw Seafood
- Store cooked seafood on racks or shelves above raw seafood in refrigerated
storage rooms. This prevents raw seafood liquids from dripping on cooked
products. Do not store cases of raw or cooked seafoods on the floor.
- Ideally, unpackaged raw and cooked seafoods should be in separate display
cases. Alternatively, display raw and cooked seafoods in separate sections of
the case. Physically separate the two sections.
Another acceptable solution is to store cooked seafoods at the front of the case
and raw seafoods at the back. This prevents raw products from passing over and
possibly dripping on cooked products. Physically separate raw and cooked
seafood.
Equipment and Utensils
- Store cooked seafoods in sanitary containers and not in containers used for
raw seafoods.
- Process seafood using sanitary knives and cutting boards. Clean and sanitize
knives and boards between processing raw and cooked products, and between
processing seafood and meat or poultry.
- Empty seafood display cases daily and remove old ice. Clean and sanitize
display cases and drains before adding fresh ice and restocking.
- Display seafood on clean sanitary ice. Place seafood in pans, trays, bowls,
or on plastic sheets rather than directly on the ice. Display cOntainers should
allow liquids to drain.
- Handle seafood in the display case with sanitary utensils or single-use
sanitary materials. Use separate utensils for each raw and cooked product.
- Place spiked price tags in garnish or ice, but not in seafood.
- Store utensils in a sanitizing solution or inside the refrigerated display
case at 29-32°F to minimize bacterial growth.
- Keep the surface of the scale sanitary. Protect the scale by placing seafood
on single-use paper or plastic material. Clean and sanitize scale if any food
comes in contact with the surface.
- Clean up spills with single-service towels. Do not use cleaning cloths or
sponges which may contain unwanted bacteria.
Seafood Handlers
- Wear a clean apron or coat. Clothing can spread unwanted bacteria to
seafoods. Do not use apron or coat to clean or dry hands or utensils.
- Wear a hair net or hat to keep hair from falling onto and contaminating
seafoods. Hair contains millions of bacteria.
- Always work with clean hands. Avoid touching your face, nose or clothing.
Wash and sanitize hands between handling raw and cooked seafoods, between
handling food and money, and whenever they touch anything other than sea food.
Dry your hands with single-use paper towels.
- Do not handle seafood if you have unprotected cuts or sores. Cuts and sores
often contain illness-causing bacteria.
- Handle raw and cooked seafoods with sanitary gloves. Do not handle raw and
cooked products with the same gloves. Wash and sanitize your gloves every time
they touch anything other than seafood.
- Sneeze and cough into a tissue and away from seafood. Never chew gum, smoke,
eat or drink while handling seafood.
- Remove watches, rings and jewelry. Jewelry carries un-wanted bacteria.
- Inform your supervisor if you are ill.
The Environment
- Insects and flies carry illness causing bacteria. Keep insects and flies
away from seafood.
- Store garbage and processing wastes in sealed containers away from display
areas.
Sources of Potential Illness Causing Microorganisms in Seafood
1. Microorganisms Naturally Present in Aquatic Environments
| Microorganism | Illness | Seafoods Involved |
| Aeromonas hydrophila | Gastroenteritis
| Raw oysters |
| Clostridium botulinum | Botulism |
Smoked, salted and fermented seafoods |
| Plesiomonas shigelloides |
Gastroenteritis | Raw and under cooked oysters, salt mackerel |
| Vibrio hollisae | Gastroenteritis
| Raw seafoods |
| Vibrio mimicus | Gastroenteritis |
Raw oysters, boiled crayfish |
| Vibrio parahaemolyticus |
Gastroenteritis | Raw oysters, contaminated cooked seafood |
| Vibrio vulnificus | Septicemia |
Raw oysters |
2. Microorganisms From Sewage Pollution of Aquatic Environments
| Microorganism | Illness | Seafoods Involved |
| Pathogenic Escherichia coli |
Gastroenteritis | Contaminated cooked crabmeat |
| Salmonella typhi | Typhoid fever |
Raw oysters |
| Vibrio cholerae O1 | Cholera |
Raw oysters, contaminated cooked crab |
| Vibrio cholerae non-O1 |
Gastroenteritis | Raw oysters |
| Hepatitis A virus | Infectious hepatitis |
Raw shellfish |
| Norwalk virus | Gastroenteritis | Raw and steamed
shellfish |
3. Microorganisms From Seafood Handlers, Equipment, and the Environment
| Microorganism | Illness | Seafoods Involved |
| Clostridium perfringens |
Gastroenteritis | Cooked seafood held below 140°F
|
| Listeria monocytogenes | Septicemia
| Possibly shellfish and raw fish |
| Salmonella | Gastroenteritis | Contaminated cooked seafood held at 40-140°F |
| Shigella | Gastroenteritis |
Contaminated cooked seafood held at 40-140°F |
| Staphylococcus aureus |
Gastroenteritis | Contaminated cooked seafood held at 40-140°F |
The author is Robert J. Price, Ph.D., Extension Seafood Technology Specialist
Department of Food Science & Technology, University of California, Davis,
California 95616
UCSGEP 90-6 August 1990
TThis work is sponsored in part by NOAA, National Sea Grant College Program,
Department of Commerce, under grant number NA89AA-D-SG138, project number
A/EA-1, through the California Sea Grant College Program, and in part by the
California State Resources Agency. The U.S. Government may reproduce and
distribute reprints for governmental purposes.
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