Source and Control of Cross Contamination in Food Factory
Cross contamination is a problem that cannot be ignored in food processing. However, since cross contamination may occur in multiple parts,
it is often overlooked. Here, WONE is going to share a review of the issue of cross contamination.
Cross contamination refers to the process in which biological, chemical contaminants or foreign matter in raw materials, intermediate products
, products to be packaged, and finished products are transferred to post-process products through processed products, food processors, food
processing environments or tools during the production, processing, storage, transportation, and sales of food.
Although cross contamination may occur in multiple processes of production, as long as the cause and method of contamination are known, it
can be effectively prevented.
For example: In the planning of the flow of people, the principle should be from high cleanliness area to low cleanliness area, that is, the
movement of people is from clean area to quasi-clean area then to contaminated area; as for the flow of logistics, it is just the opposite, from
low cleanliness area to high cleanliness area, that is, from contaminated area to quasi-clean area then to clean area.
No distinction between raw and cooked mainly includes no distinction between raw and cooked areas, raw and cooked employees, raw and
cooked utensils, raw and cooked foods, etc.
No distinction between raw and cooked areas is mainly due to the fact that there are both raw products or biological materials and cooked
products or semi-cooked materials in the same area, and the two materials with different degrees of cookedness have different hygiene and
safety requirements. Therefore, the two materials will be seriously cross-contaminated in the same area. No distinction between raw and
cooked employees is mainly due to the fact that the hygiene protection control of employees processing raw products and the hygiene control
of employees processing cooked foods have completely different requirements. If raw product operators enter the cooked product processing
workshop, there will occur cross contamination.
At the same time, if the operators in the cooked product workshop shuttle back and forth between the raw and cooked workshops, serious
cross contamination will also occur. No distinction between raw and cooked utensils refers to the use of utensils for holding, transporting,
cutting, processing, etc. for raw and cooked products at the same time, and the utensils are not thoroughly cleaned and disinfected during the
period, and there is no evidence that the cleanliness of the utensils can meet the processing requirements of cooked products and cause
cross contamination. Undifferentiated raw and cooked food means mixing raw and cooked products and placing them in the same utensil or
packaging container, causing serious cross contamination.
In summary, whether it is cross contamination caused by regions, personnel, etc., or cross contamination caused by utensils, etc., it will cause
serious food insecurity and risks. Therefore, effective measures should be taken to prevent cross contamination caused by undifferentiated
raw and cooked food.
2. Improper disinfection of equipment, facilities, utensils, etc.
Improper disinfection of equipment, facilities, utensils, etc., and their hygiene level does not meet the specified requirements, will cause cross
contamination to processed materials, especially equipment that directly contacts processed materials. Improper disinfection of the interior
and surface of equipment and facilities will cause the growth of microorganisms and residues of chemical reagents, especially dead corners
that are not easy to clean, such as pipelines, conveyor belts, hoppers, and tanks. Improper cleaning and disinfection will cause cross contami-
nation of processed products and mixing of products from different batches, affecting food safet
3. Improperly disinfected bare hands contact unpackaged finished products
The hands of processing operators and their gloves, collars, etc. are parts that frequently contact food. If bare hands are not strictly disinfected
or are improperly disinfected, harmful microorganisms and physical impurities may exist on the surface of the hands, nails, etc., which will
cause cross-contamination when the hands touch food; if employees wear gloves during food processing, the glove material must first be food
grade, and then they can go to work after strict toxic cleaning. The same applies to the collars worn by employees.
When employees enter and leave the workshop, such as entering and leaving the toilet or touching non-clean parts, they must disinfect and
clean their bare hands before entering the workplace, otherwise they will bring in a large number of E. coli and Salmonella, etc., causing cross-
contamination. If ready-to-eat food is produced and the food has microbial hygiene requirements, some intermediate production processes also
require disinfection of bare hands.
In principle, employees are not allowed to enter the workshop without changing clothes and washing hands after entering the toilet. That is to
say, there is a problem with the toilet setting at this location. Whether the disinfection of bare hands and other direct contact surfaces is
appropriate and effective needs to be verified through microbial smear tests.
4. Improper storage of waste in the processing area
It is inevitable that some waste will be generated in the processing workshop. If the protection of these wastes is not handled properly, cross-
contamination of processed food will occur. For example, the storage of the inner packaging materials after removal in the processing workshop,
the storage of food on the ground, etc.; especially the overflow of garbage and waste in the trash cans in the clean workshop, the incorrect
storage of sanitary cleaning tools, and the contact of waste with bare hands, etc., will cause cross-contamination of food.
Food processing personnel should undergo health examinations and obtain health certificates every year; they should receive health training
before taking up their posts to improve the skills of food practitioners in controlling food contamination
If food processing personnel suffer from digestive tract infectious diseases such as dysentery, typhoid fever, hepatitis A, hepatitis E, as well as
active pulmonary tuberculosis, purulent or exudative skin diseases and other diseases that hinder food safety, or have obvious skin injuries that
have not healed, they should be transferred to other jobs that do not affect food safety to prevent the occurrence of human pollution.
When entering the work area, you should wear clean work clothes and wash and disinfect your hands as required; your hair should be hidden in
a work hat or restrained with a hair net.
After going the toilet, touching items that may contaminate food, or engaging in other activities not related to food production, you should wash
your hands and disinfect them before engaging in activities related to food production such as contact with food, food utensils, and food
equipment.
Non-food processing employees are not allowed to enter food production sites, and are not allowed to randomly visit other posts. When entering
under special circumstances, they should comply with the same hygiene requirements as food processing personnel.
2. Food procurement pollution control measures
Implement quality management of raw material procurement acceptance, strictly control the quality of raw materials, and do not use raw materials
that do not meet the requirements, and implement quality veto power.
The raw materials and additives used must comply with national standards, industry standards, and relevant health standards and regulations,
and products with illegal abuse of additives must be eliminated.
Take necessary measures to ensure that the quality of food deteriorates during transportation. Finished products and pollutants must not be
transported in the same vehicle during transportation.
3. Food storage pollution control measures
Raw materials and finished products should be stored away from the ground and walls (they can be placed on the ground flat plate), stored in
categories, and can be stored in isolation when necessary. Regular inspections should be carried out to deal with spoiled or expired food.
Warehouses should be kept clean, free of mold, stagnant water, and mosquitoes; warehouses should be well ventilated, and toxic, harmful, and
personal items should not be stored. If mold appears on the wall, it must be re-painted with lime water as soon as possible to avoid contaminating
the raw materials and finished products in the entire warehouse and workshop.
Chemicals should be stored in a designated dry and well-ventilated place to prevent food contamination.
Packaging materials should be prevented from damage and contamination during storage, and should be disinfected with ultraviolet light before
use.
4. Food processing pollution control measures
Food production and processing must have production equipment, process equipment and related instruments to ensure product quality, and
hardware facilities such as raw material processing, processing, and storage that are suitable for ensuring product quality.
The process flow of food production and processing should be scientific and reasonable, with separate channels for people and logistics. The
production and processing process should be strict and standardized, and necessary measures should be taken to prevent cross-contamination
of food.
There should be no harmful gases, radioactive substances and diffuse pollution sources around food production and processing, and no
mosquitoes; corresponding effective measures to prevent rats, mosquitoes and flies should be set up to avoid endangering food quality and
safety.
The transportation of food processing should have special tools that meet food requirements to prevent transportation pollution.
5. Waste pollution prevention and control measures
A waste storage and removal system should be formulated, and the treatment of waste with special requirements should comply with relevant
regulations. Waste should be removed regularly; perishable waste should be removed as soon as possible; waste should be removed in time
when necessary.
The waste storage area outside the workshop should be isolated from the food processing area to prevent pollution; bad odors or harmful and
toxic gases should be prevented from overflowing; pests should be prevented from breeding.
Food residues and debris that fall on the ground or remain in the machine during the production process must be cleaned out first after the
operation is completed, and then cleaned and disinfected, otherwise it is easy to cause mold.
6. Formulate a cleaning and disinfection system
According to the characteristics of raw materials, products and processes, an effective cleaning and disinfection system should be formulated for
production equipment, tools and environment to reduce the risk of microbial contamination.
The cleaning and disinfection system should include the following: the name of the area, equipment or tools for cleaning and disinfection; the
responsibilities of cleaning and disinfection work; the detergents and disinfectants used; the cleaning and disinfection methods and frequency; the
verification of the cleaning and disinfection effect and the handling of non-compliance; cleaning and disinfection work and monitoring records.
Ensure the implementation of the cleaning and disinfection system and record it truthfully; verify the disinfection effect in a timely manner and
correct problems in a timely manner.
Cleaning tools (brooms, mops, etc.) should be placed in designated locations outside the workshop and should not be placed in the workshop to
avoid contamination.
7. Control of chemical contamination
A management system should be established to prevent chemical contamination, analyze possible sources and pathways of contamination, and
formulate appropriate control plans and control procedures.
A system for the use of food additives and processing aids for the food industry should be established, and food additives should be used in
accordance with the requirements of GB2760.
Non-edible chemicals other than food additives and other substances that may harm the human body shall not be added in food processing.
If the moving parts on the production equipment that may directly or indirectly contact food need to be lubricated, edible oil or other oil that can
ensure food safety requirements should be used.
Establish a system for the use of chemicals such as detergents and disinfectants. Except for cleaning and disinfection and process requirements,
chemical preparations that may contaminate food should not be used and stored in the production site.
Food additives, detergents, disinfectants, etc. should be properly stored in appropriate containers, and should be clearly marked and stored in
categories; when they are used, they should be accurately measured and records of use should be kept.
Attention should be paid to the situation where harmful substances may be produced during food processing, and effective measures should be
encouraged to reduce their risks.
8. Control of physical contamination
A management system should be established to prevent foreign body contamination, analyze possible sources and routes of contamination, and
formulate corresponding control plans and control procedures.
The risk of food being contaminated by foreign bodies such as glass, metal (such as rust), plastic, and hair should be minimized by taking
measures such as equipment maintenance, hygiene management, on-site management, management of external personnel, and supervision of
the processing process.
Effective measures such as setting up screens, traps, magnets, metal detectors, etc. should be taken to reduce the risk of metal or other foreign
matter contaminating food.
When performing on-site repairs, maintenance and construction work, appropriate measures should be taken to prevent foreign matter, odors,
debris, etc. from contaminating food.
