Thursday, May 31, 2007
GM Food (Introduction)
Genetically Modified (GM) foods are produced from genetically modified organisms (GMO) which have had their genome altered through genetic engineering techniques. The general principle of producing a GMO is to insert DNA that has been taken from another organism and modified in the laboratory into an organism's genome to produce both new and useful traits or phenotypes. Typically this is done using DNA from certain types of bacteria.
Tuesday, May 15, 2007
Interesting Facts To Know About Gram +ve VS Gram -ve Microbes
Gram +ve Microbes
Gram -ve Microbes
Gram negative cells tend to be more susceptible to heat and disinfectants as compared to Gram positive. Furthermore, Gram-positive rods tend to have spores while Gram negative bacteria do not. The Gram reaction is a reproducible characteristic of a species and therefore is an additional tool for bacterial identification.
Vacuum packaging can extend the shelf life of some products. This procedure inhibits the Gram-negative bacteria that require oxygen for growth; thus the production of foul odors is delayed. The growth of Gram-positive bacteria, that are also present in the vacuum-packaged product, is a little slower and their metabolic products are not as objectionable. Thus vacuum packaging does not stop spoilage, it only alters the spoilage rate and the nature of spoilage flora. Vacuum packaging, however, carries with it a serious potential hazard because if the product is temperature abused, Clostridium botulinum will be able to grow.
Gram-negative bacteria, such as Pseudomonas, tend to produce more foul odors than Gram-positive bacteria, such a Bacillus or Streptococcus species. Off odors (incipient spoilage) are usually detected when bacterial numbers reach 106 to 107 CFU/G of the product.
Monday, May 7, 2007
Information for Different Ingredient Group
Below are the information needed for Template 4, identification of predominant microbes in our group of ingredient. In addition, other important information regarding critical limits etc.
1. Meat and poultry products
1.1. Types of products
Raw meat and poultry products consist of raw products; shelf-stable, raw-salted and salted-cured products (salt pork, dry-cured bacon, country ham); perishable raw-salted and salted-cured products (fresh sausage, chorizo, bratwurst, Polish and Italian sausage); marinated products; and raw breaded products. Ready-to-eat products include perishable cooked uncured products (cooked roast beef, cooked pork, cooked turkey); perishable cooked cured products (franks, bologna, ham, and a variety of luncheon meats); canned shelf-stable cured products (Vienna sausages, corned beef, meat spreads, small canned hams, canned sausages with oil and water activity [aw] <0.92, dried beef, and prefried bacon); perishable canned cured products (ham and other cured meats); shelf-stable, canned uncured products (roast beef with gravy, meat stew, chili, chicken and spaghetti sauce with meat); fermented and acidulated sausages (German and Italian style salamis, pepperoni, Lebanon bologna, and summer sausage); and dried meat products (jerky, beef sticks, basturma, and other dried meats). Because of the complexity of the product/processing matrices, product parameters (moisture protein ratio, aw, and pH) and processing schedules are needed to ascertain whether ready-to-eat products require time/temperature control for safety or are shelf stable.
1.2. Microbial concerns
Red meats and poultry come from warm-blooded animals and, as such, their microbial flora is heterogeneous, consisting of mesophilic and psychrotrophic bacteria. These bacteria include pathogenic species from the animal itself and from the environment, and bacterial species introduced during slaughter and processing of raw products. Raw meat and poultry have an aw >0.99 and a pH range of 5 -7, which is an optimal combination for microbial growth. When red meats and poultry are cooked or processed and subsequently refrigerated, the bacterial load from the raw tissue is greatly reduced, leaving only spore-formers, enterococci, micrococci, and some lactobacilli. In addition, environmental post-processing pathogen contamination can occur and the reduction in competitive bacterial flora may allow for pathogen growth. Some products are shelf stable because they received either a botulinum cook or a lesser cook in combination with other controls, such as acidity or other additives (for example, spaghetti meat sauce and Sloppy Joe mix).
1.3. Pathogens of concern
The principal pathogens of concern are Staphylococcus aureus, enterohemmorrhagic Escherichia coli (ruminants), Salmonella spp. (all meats), Listeria monocytogenes (all meats), Campylobacter jejuni/coli (poultry), Yersinia entercolitica (pork), and Clostridium perfringens and Clostridium botulinum (mainly processed products). There is a particular concern when these species are present and/or can grow in cooked products without competition.
1.4. Effects of processing
Meat and poultry products require a wide array of control measures in their processing. Cured meats and some sausage products utilize additives such as salt, nitrate, nitrite, and sugars with processing procedures such as cooking and smoking. Salt, for example, may restrict bacterial flora to salt-tolerant species. Smoking and/or cooking will destroy many vegetative cells. However, the processing environment and product handling and packaging may introduce microorganisms, including pathogens, into the packaged product that also must be considered.
While some canned products may be processed as "commercially sterile", others are canned "semi-preserved" and must be stored under refrigeration. Some products utilize a secondary control such as acidity and are shelf stable though not necessarily "commercially sterile." Specific labeling for refrigeration is required on the semi-preserved products that require refrigeration as a control. Pickled products depend on a low pH, absence of oxygen, and the lack of a fermentable sugar to inhibit the growth of most bacteria. Acid-tolerant species may develop, such as certain lactobacilli, and if air is available, certain yeast and molds may grow. The activity of lactic acid bacteria in fermented sausages is desirable and is an integral part of the process control for achieving the desired pH for these products.
Because of the complexities of products and processing, the USDA Food Safety and Inspection Service (FSIS) has provided guidelines for product parameters in its "Food Standards and Labeling Policy Book" (USDA 1996, with change 98-01). The FSIS guidelines include product specifications such as "meat sticks and cheese", along with general topic categories such as for example "Sausage - Shelf Stable"; "Moisture Protein Ratio -MPR;" and "Moisture Protein Ratio - pH." These policies must always be considered in conjunction with process controls under the HACCP Rule, 9 C.F.R. 417. A product processed in the retail environment is not covered by this rule; however, the variance requirements of the Food Code should require that meat and poultry products have equivalent product specifications for shelf stability and process records documenting control of hazards.
There is substantial history of safety of meat and poultry products that meet these criteria. In addition to the above criteria, certain combinations of pH, aw, and /or other factors can be used to prevent pathogen level increase when meat products are held at ambient temperatures. Products processed in the retail environment and exempt from the HACCP Rule should also follow these guidelines and maintain records documenting control of hazards.
1.5. Time/temperature control
Unless the specific product parameters referenced in the previous section are met, meat and poultry products must be considered as requiring time/temperature control. Raw meat and poultry products currently require safe-handling instruction labeling that includes a time/temperature control provision. For ready-to-eat foods, product parameters and processing schedules are needed to ascertain whether temperature control for safety is required. Post-processing contamination is also an important consideration and should not be overlooked. Because meat offers a rich nutrient media for microbial growth, products that incorporate meat and poultry as ingredients, such as meat salads and meat pastries, also must be considered as requiring time/temperature control.
2. Cereal grains and related products
2.1. Types of products
Cereal grains and related products include baked goods (breads, muffins, cakes, pastries, cookies, biscuits, bagels, and so on), frozen and refrigerated dough, breakfast cereals (cold cereal, oatmeal, grits, and so on), refrigerated or dry pasta and noodles, and cooked grains (for example, rice). Some products, such as baked goods, have a long history of safe storage at room temperature; others, such as rice, require time/temperature control after preparation.
2.2. Pathogens of concern
Grains and milled products are raw agricultural commodities; therefore, a variety of microorganisms, including mold, yeast, coliforms and other bacteria, occur naturally. Grains and milled products are dried to inhibit mold growth during storage, a process that easily controls growth of bacterial pathogens. Therefore, while organisms such as Salmonella spp. may be present, the prevalence and levels are low (usually <1%). Raw ingredients used to prepare dough products (for example, eggs, dairy products, meats) may introduce Salmonella spp., and need to be considered when analyzing potential hazards. Staphylococcus aureus may present a potential hazard for certain raw dough, such as pasta dough processed at warm temperatures for extended periods of time (days); however, yeast leavened dough and cookie dough control the organism through competitive inhibition and low aw , respectively. Bacillus cereus presents a concern in cooked rice.
2.3. Effects of processing
Baking, boiling, steaming, or frying are the methods used to cook the cereal-grain products. The temperatures required to achieve product quality easily destroy vegetative pathogens that may be present. These temperatures are needed to properly set the starch structure and/or to rehydrate dry products. Baking and frying not only destroy vegetative pathogens such as S. aureus and Salmonella spp., but they also remove moisture from the product-especially at the exterior surface. This dehydrated surface inhibits the growth of most bacteria; thus, mold is the primary microbial mode of failure for baked goods. When stored at room temperature, baked and fried products typically continue to lose moisture to the atmosphere, further reducing the potential for pathogen growth. Thus, baked and fried cereal-grain products such as cakes, breads, muffins, and biscuits have a long history of safe storage at room temperature despite having an internal aw of approximately 0.94-0.95 (but may be as high as 0.98).
While boiled or steamed cereal products achieve temperatures lethal to vegetative pathogens during the cooking process, these products increase in aw to levels that support the growth of many microbial pathogens. Thus, time/temperature control is required to assure the safety of these products. For example, numerous B.cereus outbreaks have been associated with fried rice prepared using boiled rice that was held for hours at room temperature.
2.4. Time/temperature control
Although baked and fried cereal-grain products (for example, cakes, breads, muffins, and biscuits) have a high aw, a number of reasons may justify their shelf-stability: they have a long history of safe storage at ambient temperature; processing temperatures and moisture reduction, especially on the surface, preclude the growth of pathogens; and they are often formulated to include ingredients that enhance product safety and stability so as to permit distribution without temperature control for limited periods of time. Ingredients that are used to enhance safety and stability include humectants to reduce aw (sugars and glycerine), preservatives (calcium propionate, potassium sorbate, sorbic acid), acids to reduce pH (vinegar, citric acid, phosphoric acid, malic acid, fumaric acid), spices with antimicrobial properties (cinnamon, nutmeg, garlic), and water-binding agents to control free water (gums, starches). The primary mode of spoilage of baked goods is mold growth, which is visible and alerts the consumer to avoid consumption, further reducing the risk of illness due to spoiled product. These characteristics plus their long history of safe storage at room temperature would allow these products to be stored at ambient temperature. Boiled or steamed cereal products, such as rice, require time/temperature control after preparation due to the increase in aw.
Dough is frequently used to enrobe other food ingredients. Careful consideration must be given to these combination products to accurately assess the need for time/temperature control. For example, egg and dairy ingredients baked inside a pastry, such as cream-cheese croissant, will receive sufficient heat treatments to destroy vegetative pathogens and may therefore be stable at room temperature with water activities above 0.86. However, if the filling is injected after the baking process, as in the case of a cream-filled éclair, the potential for contamination must be assessed. Meat and vegetable-filled cereal products with high water activities (>0.94) and neutral pH generally require time/temperature control because the baking process can activate spore formers such as C. botulinum that are present in these ingredients.
1. Meat and poultry products
1.1. Types of products
Raw meat and poultry products consist of raw products; shelf-stable, raw-salted and salted-cured products (salt pork, dry-cured bacon, country ham); perishable raw-salted and salted-cured products (fresh sausage, chorizo, bratwurst, Polish and Italian sausage); marinated products; and raw breaded products. Ready-to-eat products include perishable cooked uncured products (cooked roast beef, cooked pork, cooked turkey); perishable cooked cured products (franks, bologna, ham, and a variety of luncheon meats); canned shelf-stable cured products (Vienna sausages, corned beef, meat spreads, small canned hams, canned sausages with oil and water activity [aw] <0.92, dried beef, and prefried bacon); perishable canned cured products (ham and other cured meats); shelf-stable, canned uncured products (roast beef with gravy, meat stew, chili, chicken and spaghetti sauce with meat); fermented and acidulated sausages (German and Italian style salamis, pepperoni, Lebanon bologna, and summer sausage); and dried meat products (jerky, beef sticks, basturma, and other dried meats). Because of the complexity of the product/processing matrices, product parameters (moisture protein ratio, aw, and pH) and processing schedules are needed to ascertain whether ready-to-eat products require time/temperature control for safety or are shelf stable.
1.2. Microbial concerns
Red meats and poultry come from warm-blooded animals and, as such, their microbial flora is heterogeneous, consisting of mesophilic and psychrotrophic bacteria. These bacteria include pathogenic species from the animal itself and from the environment, and bacterial species introduced during slaughter and processing of raw products. Raw meat and poultry have an aw >0.99 and a pH range of 5 -7, which is an optimal combination for microbial growth. When red meats and poultry are cooked or processed and subsequently refrigerated, the bacterial load from the raw tissue is greatly reduced, leaving only spore-formers, enterococci, micrococci, and some lactobacilli. In addition, environmental post-processing pathogen contamination can occur and the reduction in competitive bacterial flora may allow for pathogen growth. Some products are shelf stable because they received either a botulinum cook or a lesser cook in combination with other controls, such as acidity or other additives (for example, spaghetti meat sauce and Sloppy Joe mix).
1.3. Pathogens of concern
The principal pathogens of concern are Staphylococcus aureus, enterohemmorrhagic Escherichia coli (ruminants), Salmonella spp. (all meats), Listeria monocytogenes (all meats), Campylobacter jejuni/coli (poultry), Yersinia entercolitica (pork), and Clostridium perfringens and Clostridium botulinum (mainly processed products). There is a particular concern when these species are present and/or can grow in cooked products without competition.
1.4. Effects of processing
Meat and poultry products require a wide array of control measures in their processing. Cured meats and some sausage products utilize additives such as salt, nitrate, nitrite, and sugars with processing procedures such as cooking and smoking. Salt, for example, may restrict bacterial flora to salt-tolerant species. Smoking and/or cooking will destroy many vegetative cells. However, the processing environment and product handling and packaging may introduce microorganisms, including pathogens, into the packaged product that also must be considered.
While some canned products may be processed as "commercially sterile", others are canned "semi-preserved" and must be stored under refrigeration. Some products utilize a secondary control such as acidity and are shelf stable though not necessarily "commercially sterile." Specific labeling for refrigeration is required on the semi-preserved products that require refrigeration as a control. Pickled products depend on a low pH, absence of oxygen, and the lack of a fermentable sugar to inhibit the growth of most bacteria. Acid-tolerant species may develop, such as certain lactobacilli, and if air is available, certain yeast and molds may grow. The activity of lactic acid bacteria in fermented sausages is desirable and is an integral part of the process control for achieving the desired pH for these products.
Because of the complexities of products and processing, the USDA Food Safety and Inspection Service (FSIS) has provided guidelines for product parameters in its "Food Standards and Labeling Policy Book" (USDA 1996, with change 98-01). The FSIS guidelines include product specifications such as "meat sticks and cheese", along with general topic categories such as for example "Sausage - Shelf Stable"; "Moisture Protein Ratio -MPR;" and "Moisture Protein Ratio - pH." These policies must always be considered in conjunction with process controls under the HACCP Rule, 9 C.F.R. 417. A product processed in the retail environment is not covered by this rule; however, the variance requirements of the Food Code should require that meat and poultry products have equivalent product specifications for shelf stability and process records documenting control of hazards.
There is substantial history of safety of meat and poultry products that meet these criteria. In addition to the above criteria, certain combinations of pH, aw, and /or other factors can be used to prevent pathogen level increase when meat products are held at ambient temperatures. Products processed in the retail environment and exempt from the HACCP Rule should also follow these guidelines and maintain records documenting control of hazards.
1.5. Time/temperature control
Unless the specific product parameters referenced in the previous section are met, meat and poultry products must be considered as requiring time/temperature control. Raw meat and poultry products currently require safe-handling instruction labeling that includes a time/temperature control provision. For ready-to-eat foods, product parameters and processing schedules are needed to ascertain whether temperature control for safety is required. Post-processing contamination is also an important consideration and should not be overlooked. Because meat offers a rich nutrient media for microbial growth, products that incorporate meat and poultry as ingredients, such as meat salads and meat pastries, also must be considered as requiring time/temperature control.
2. Cereal grains and related products
2.1. Types of products
Cereal grains and related products include baked goods (breads, muffins, cakes, pastries, cookies, biscuits, bagels, and so on), frozen and refrigerated dough, breakfast cereals (cold cereal, oatmeal, grits, and so on), refrigerated or dry pasta and noodles, and cooked grains (for example, rice). Some products, such as baked goods, have a long history of safe storage at room temperature; others, such as rice, require time/temperature control after preparation.
2.2. Pathogens of concern
Grains and milled products are raw agricultural commodities; therefore, a variety of microorganisms, including mold, yeast, coliforms and other bacteria, occur naturally. Grains and milled products are dried to inhibit mold growth during storage, a process that easily controls growth of bacterial pathogens. Therefore, while organisms such as Salmonella spp. may be present, the prevalence and levels are low (usually <1%). Raw ingredients used to prepare dough products (for example, eggs, dairy products, meats) may introduce Salmonella spp., and need to be considered when analyzing potential hazards. Staphylococcus aureus may present a potential hazard for certain raw dough, such as pasta dough processed at warm temperatures for extended periods of time (days); however, yeast leavened dough and cookie dough control the organism through competitive inhibition and low aw , respectively. Bacillus cereus presents a concern in cooked rice.
2.3. Effects of processing
Baking, boiling, steaming, or frying are the methods used to cook the cereal-grain products. The temperatures required to achieve product quality easily destroy vegetative pathogens that may be present. These temperatures are needed to properly set the starch structure and/or to rehydrate dry products. Baking and frying not only destroy vegetative pathogens such as S. aureus and Salmonella spp., but they also remove moisture from the product-especially at the exterior surface. This dehydrated surface inhibits the growth of most bacteria; thus, mold is the primary microbial mode of failure for baked goods. When stored at room temperature, baked and fried products typically continue to lose moisture to the atmosphere, further reducing the potential for pathogen growth. Thus, baked and fried cereal-grain products such as cakes, breads, muffins, and biscuits have a long history of safe storage at room temperature despite having an internal aw of approximately 0.94-0.95 (but may be as high as 0.98).
While boiled or steamed cereal products achieve temperatures lethal to vegetative pathogens during the cooking process, these products increase in aw to levels that support the growth of many microbial pathogens. Thus, time/temperature control is required to assure the safety of these products. For example, numerous B.cereus outbreaks have been associated with fried rice prepared using boiled rice that was held for hours at room temperature.
2.4. Time/temperature control
Although baked and fried cereal-grain products (for example, cakes, breads, muffins, and biscuits) have a high aw, a number of reasons may justify their shelf-stability: they have a long history of safe storage at ambient temperature; processing temperatures and moisture reduction, especially on the surface, preclude the growth of pathogens; and they are often formulated to include ingredients that enhance product safety and stability so as to permit distribution without temperature control for limited periods of time. Ingredients that are used to enhance safety and stability include humectants to reduce aw (sugars and glycerine), preservatives (calcium propionate, potassium sorbate, sorbic acid), acids to reduce pH (vinegar, citric acid, phosphoric acid, malic acid, fumaric acid), spices with antimicrobial properties (cinnamon, nutmeg, garlic), and water-binding agents to control free water (gums, starches). The primary mode of spoilage of baked goods is mold growth, which is visible and alerts the consumer to avoid consumption, further reducing the risk of illness due to spoiled product. These characteristics plus their long history of safe storage at room temperature would allow these products to be stored at ambient temperature. Boiled or steamed cereal products, such as rice, require time/temperature control after preparation due to the increase in aw.
Dough is frequently used to enrobe other food ingredients. Careful consideration must be given to these combination products to accurately assess the need for time/temperature control. For example, egg and dairy ingredients baked inside a pastry, such as cream-cheese croissant, will receive sufficient heat treatments to destroy vegetative pathogens and may therefore be stable at room temperature with water activities above 0.86. However, if the filling is injected after the baking process, as in the case of a cream-filled éclair, the potential for contamination must be assessed. Meat and vegetable-filled cereal products with high water activities (>0.94) and neutral pH generally require time/temperature control because the baking process can activate spore formers such as C. botulinum that are present in these ingredients.
Aw Activity of Food To Support Different Microbial Growth
Information for Template 4. To identify the microbes that can grow in dried instant ramen and soup powder.
Sunday, May 6, 2007
Concerns For Vacuum-packed and Refrigerated Teriyaki Chicken
C. botulinum and C. perfringen are an obligate anaerobes where vegetative cells can be killed at 80degreeC in few seconds time however, being spore-forming bacteria, the endospore formed can survive the high heat treatment and will result in foodborne illness when conditions become favorable for its growth during storage. In Instant Teriyaki Chicken Ramen, the teriyaki chicken are vacuum-packed to extend its shelf-life however, no one preservation method is foolproof, the vacuum condition makes it an ideal condition for the growth of C. botulinum and C. perfringens. To help better ensure food safety, the storage condition of the final product will be kept at refrigerated condition, a temperature range of which will not support the growth of these two microbes.
Yet on the other hand, the refrigerated condition can still promote the growth of Listeria which is found in the environment and can grow at a wide temperature range, and grow as at as low as 0degreeC so, the main preventive control is to empoly aanitary safeguards to prevent reintroduction of pathogens. Chief among these is Listeria monocytogenes.
The National Advisory Committee on Microbiological Criteria for Foods (NACMCF) chartered by the U.S. Department of Agriculture (USDA) and the Department of Health and Human Services (HHS) recently commented on the microbial safety of refrigerated foods containing cooked, uncured meat or poultry products that are packaged for extended refrigerated shelf-life and are ready-to-eat or prepared with little or no additional heat treatment. The Committee recommended guidelines for evaluating the ability of thermal processes to inactivate L. monocytogenes in extended shelf-life refrigerated foods. Specifically, it recommended a proposed requirement for demonstrating that an ROP process provides a heat treatment sufficient to achieve a 4 decimal log reduction (4D) of L. monocytogenes.
Yet on the other hand, the refrigerated condition can still promote the growth of Listeria which is found in the environment and can grow at a wide temperature range, and grow as at as low as 0degreeC so, the main preventive control is to empoly aanitary safeguards to prevent reintroduction of pathogens. Chief among these is Listeria monocytogenes.
The National Advisory Committee on Microbiological Criteria for Foods (NACMCF) chartered by the U.S. Department of Agriculture (USDA) and the Department of Health and Human Services (HHS) recently commented on the microbial safety of refrigerated foods containing cooked, uncured meat or poultry products that are packaged for extended refrigerated shelf-life and are ready-to-eat or prepared with little or no additional heat treatment. The Committee recommended guidelines for evaluating the ability of thermal processes to inactivate L. monocytogenes in extended shelf-life refrigerated foods. Specifically, it recommended a proposed requirement for demonstrating that an ROP process provides a heat treatment sufficient to achieve a 4 decimal log reduction (4D) of L. monocytogenes.
Saturday, May 5, 2007
Product Recall Decision Tree
Taken from http://www.nzfsa.govt.nz/processed-food-retail-sale/recalls/guidance/index.htm
Potential Hazards Classifications
Physical hazards:
Glass
Metal
Other foreign matters
Chemical hazards:
Allergens
Animal drugs residues
Cleaning compound
Residues
Illegal residues/pesticides in raw material, packaging material, shipping containers
Natural toxins
Unapproved food additives
Overdosage of food additives
Antibodies/hormones
Biological hazards:
Cross-contamination (post processing)
Pathogen in raw materials, during storage
Parasites
Pests
Glass
Metal
Other foreign matters
Chemical hazards:
Allergens
Animal drugs residues
Cleaning compound
Residues
Illegal residues/pesticides in raw material, packaging material, shipping containers
Natural toxins
Unapproved food additives
Overdosage of food additives
Antibodies/hormones
Biological hazards:
Cross-contamination (post processing)
Pathogen in raw materials, during storage
Parasites
Pests
Friday, May 4, 2007
Food Intoxication VS Food Infection
Food Intoxication
Clostridium botulinum
Clostridium perfringens
Bacillus cereus
Staphylococcus aureus
Aspergillus sp.
Food Infection
Listeria monocytogenes
Vibrio cholerae
Vibrio parahaemolyticus
Vibrio vulnificus
Salmonella sp.
Shigella sp.
Escherichia coli
Yersinia enterocolitica
Campylobacter jejuni
Plesiomonas shigelloides
Clostridium botulinum
Clostridium perfringens
Bacillus cereus
Staphylococcus aureus
Aspergillus sp.
Food Infection
Listeria monocytogenes
Vibrio cholerae
Vibrio parahaemolyticus
Vibrio vulnificus
Salmonella sp.
Shigella sp.
Escherichia coli
Yersinia enterocolitica
Campylobacter jejuni
Plesiomonas shigelloides
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