VIỆN KIỂM NGHIỆM AN TOÀN VỆ SINH THỰC PHẨM QUỐC GIA

During storage, all food spoils or is spoiled in the short or long term due to their perishable essence. Cool/cold food products in particular have a relatively short shelf life, even when stored under refrigerated conditions. They include a wide variety of processed foods and beverages such as:

• Dairy products e.g. whipped cream desserts
• Cooked products, e.g. processed meat dishes
• Smoked or processed meat or fish, e.g. ham, smoked salmon fillets
• Convenience foods, e.g. sandwiches, vegetable salads
• Uncooked or partially cooked products, e.g. pizza, hot dogs
• Prepared fresh food products, e.g. uncooked meat, poultry, or fish, with or without vegetables
• Vacuum packaging food products

Food safety hazards can be microbiological, chemical, or physical. Besides the physical hazards such as sharp objects that can cause choking and chemical hazards such as unauthorized food additives or agricultural chemical residues, many microbiological hazards can be found in cool/cold foods since cool/cold environmental conditions may be suitable for some microorganisms to grow and survive. Some cool/cold food-related pathogens are listed below:

Microorganism	Minimum growing temperature	Minimum growing temperature	Minimum water activity	Anaerobic growth
Salmonella	4	3,8	0,92-0,95	Yes
Staphylococcus aureus	5,5	4,0	0,83	Yes
Bacillus cereus	4	4,9	0,93-0,95	Yes
Clostridium botulinum (Proteolytic A, B, F)	10	4,6	0,94	Yes
Clostridium botulinum (non-proteolytic A, B, F)	3	4,7	0,97	Yes
Listeria monocytogenes	-0,4	4,3	0,92	Yes
Escherichia coli	7-8	4,4	0,95	Yes
Escherichia coli O157:H7	6,5	4,5	0,935	Yes
Clostridium perfringens	12	4,5	0,93-0,95	Yes
Vibrio cholerae	10	5	0,97	Yes
Vibrio parahaemolyticus	5	4,9	0,94	Yes
Yersinia enterocolitica	-1,3	4,4	0,96	Yes
Aeromonas hydrophila	-0,1	<4,5	0,97	Yes

 

By time, food can be transformed badly in the microbiological, chemical, biochemical, physical and organoleptic properties at the different rates. Ultimately, the changes about microbiological and sensory attributes are the most important sign to determine whether or not a cool/cold food is still acceptable due to the safety or quality issues. Some examples of the spoilage and causes of cool/cold foods are as follows:

Food product	Quality description	Mechanism
Pre-cut fruit	Discoloration (brown cut edges)	Enzyme browning
Salad	Discoloration of mayonnaise	The brown color from the vegetable seeps into the mayonnaise
Vegetable	Withered	Loss of moisture/water
Yogurt	Loss of biological activity	The death of biological agents, beneficial bacteria
Sandwiches	The bread becomes hard	Redistribution of moisture (starch breakdown)
Fresh meat	Strange smell	Damage caused by microorganisms
Fruit juice	Strange smell and taste	Damage caused by microorganisms  (fermentation of yeast)

 

It is necessary to evaluate the stability/shelf life of the product to keep the best quality of the product to the consumers.