лекции 1-4

Lecture notes

 

Lecture 1

Introduction to the subject ofSanitary and food microbiology - the overall objectives and their importance forNational economy.

   

Food microbiology is a science is study of microorganisms causing food spooliage and foodborne illness. Using microorganisms to produce foods, for example by fermentation.

Food microbiology encompasses the study of microorganisms, which have both beneficial and deleterious effects on the quality, and safety of raw and processed meat, poultry, and egg products.

Food microbiology focuses on the general biology of the microorganisms that are found in foods including: their growth characteristics, identification, and pathogenesis.

Specifically, areas of interest which concern food microbiology are food poisoning, food spoilage, food preservation, and food legislation.

Sanitary microbiology is a science based on the detection of risks associated with the production, manufacture and consumption of foodstuffs, air and water. It has been established that environment facts determine the survival, growing and inactivation of the microorganisms. These risks are commonly associated with the presence of microbiological hazards and represent a serious problem from the Public Health viewpoint.    

The types of microorganisms in products depend on the way they have been elaborated, transportated, stored, taken or prepared before eating.

Food is the substance which gives the nutrients and energy material to living organism for its life and growth. Foods used for human beings contain carbohydrates, proteins, fats, vitamins, minerals and other growth factors. Nutritionally, human diet is more complicated than microbial nutrient requirements. Foods used for human consumption can serve as good source of nutrients for growth of microorganisms. Different types of microorganisms may contaminate foods or grow in them which include: bacteria, fungi, protozoans, helminths and viruses. The tiniest life forms are bacteria, yeasts, molds, and viruses, termed “microorganisms” because of their size (micro meaning small and organism meaning living being.

Presence and growth of microorganisms in foods meant for human or other animal consumption makes them unfit and also serves as potential source of infections to cause a number of food borne diseases. Microorganisms enter the foods at various stages and increase their population by growth to such an extent that they become harmful on consumption of such foods. Some foods may not directly support growth of microorganisms but support them by providing an environment for their survival. Such foods are called as microbial contaminated foods. Microorganisms prolong their life in such foods and make their entry into the consumer to cause diseases subsequently. Foods may be contaminated by microorganisms and their population is increased as a result of growth in foods which serve as good growth environment. Different types of microorganisms may contaminate foods or grow in them which include bacteria, fungi, protozoans, helminths and viruses. Presence of microorganisms in foods and their growth and/or production of toxins depend on various factors. Composition of foods in terms of their nutritive value, complexity, solubility, water content or water activity, pH and several other factors contribute to the contamination, growth of microorganisms and formation of microbial products as toxins harmful to human or animal health. Food contamination or infection may occur at various stages starting from harvesting of food grains, post harvest processing, storage, food preparation for consumption, method of preparation and preservation, period of preservation, hygienic status of persons involved in processing or preparation of foods etc. Types of microorganisms and their number may also vary based on various factors as mentioned above. All these contribute to the microbiological quality of foods and their safety to the consumer.

Food spoilage.Food spoilage is an undesirable changes in: Appearance, Texture, Odor, Flavor, Slime Formation.Which then make them unacceptable for consumption.

It is when we observed: Organoleptic changes, Chemical changes in food, Physical damage, Freezer burn, Staling, Over-ripe fruits and vegetables

It is when we observed: Presence of foreign bodies, Chemical contamination.

Classification of food: Highly perishable, Semiperishable, Nonperishable.

Food poisoning. The term “food poisoning” means poisoning caused to consumer by consumption of food laden with microorganisms. It is used very loosely to include both illnesses caused by the ingestion of toxins elaborated by microorganisms and those resulting from infection of the host through the intestinal tract. Generally food poisoning occurs when people consume food containing a toxin made by a microorganism. Bacterial food intoxication therefore refers to food borne illnesses caused by the presence of bacterial toxin(s) formed in food by bacteria in food(s). A bacterial food infection refers to food borne illnesses caused by the entrance of bacteria into the body through ingestion of contaminated foods and the reaction of the body to their presence or to their metabolites. There are several kinds of food poisoning caused by microorganisms, the most familiar examples are botulism caused by toxins of Clostridium botulinum and staphylococcal food poisoning due toxins produced by Staphylococcus aureus. Staphylococcal food poisoning is one of the most common. The most dreaded food poisoning is botulism, because of the deadly toxin produced by the causative agent. Careless storage or handling of food can cause very unpleasant and sometimes dangerous symptoms. Food is essential for every human being for life and its contamination or infection and subsequent manifestation of diseases through food is the well known phenomenon in human 3 health. The food borne diseases either by food infection or intoxication can be generally grouped as given below based on the causative agent and its manifestation into a disease.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Lecture 2

Sanitary and microbiological study of the environment (air, water and soil).

 

The study of the sanitary and bacteriological objects of external environment is needed for warning development of infections, understanding of infection origin. For example, the absence of coliforms in a water sample does not give absolute assurance of the absence of pathogenic organisms, but it is a good indication. Certain other types of microbial pathogens such as viruses (hepatitis A, poliomyelitis, norovirus) and protozoa (giardia, cryptosporidium, entamoeba) can be present in the absence of bacterial indicators. Experience has shown that disinfection of water supplies to achieve zero coliform counts has generally been successful at preventing water-borne disease. Therefore every specialist must know the basic ways of pathogens transmission, to know the basic bacteriological indicators of contamination of external environment objects, able to estimate the results of sanitary and bacteriological examination. Primary objective: to be able to conduct and evaluate the sanitary and bacteriological investigation of water, soil, air, and foodstuffs.   

The bacteriological analysis of air (aeromicroflora) at the level of dental cabinets is of a sanitary order, allowing characterization from a hygienic point of view, the environment’s potential as well as the quality of cleaning, disinfection, ventilation, etc. carried out at the level of the cabinets. The aerogenic contamination can be done with pathogenic agents coming from the patients or healthy carriers from the nasal/pharynx flora, oral cavity and/or bronchial secretion, from the skin and the digestive tract. The survival of pathogenic microorganisms depends on their resistance in the outer environment, on the nature of the object and the environmental conditions. The environmental conditions which favor the survival of microorganisms are especially represented by the absence of light, particularly of direct solar radiations, high humidity and low temperature.

Microbiology of Water. Study of microorganisms and their communities in water environment is called Aquatic microbiology. — The scope of Aquatic Microbiology is wide and includes the habitats like planktons, benthos, microbial mats and biofilm which may be found in lakes, rivers, streams, seas, groundwater, rain, snow and hail. Water Microbiology

Water born diseases.H2O can act as a vector for the transmission of bacterial, viral and protozoan agents which cause a variety of diseases (mainly intestinal) — It can also be linked to worm invasions and viral/protozoan diseases transmitted by insects (aquatic hosts or insect breeding in H2O - indirect) — Water is responsible for, by some estimates, approximately 80% of all infectious disease not just waterborne diseases, but any disease where water plays a role.

Water contains a variety of microbes including: Viruses, Bacteria, Protozoa, Helminth, Fungi.

Water born diseases. Example: Bacterial Infection Cholera — Microbial Agent: Vibrio choleraSources of Agent Drinking water contaminated with the bacterium;Typhoid fever — Microbial Agent: Salmonella typhilSources of Agent Drinking water contaminated with the bacterium; Viral Infection Infectious hepatitis — Microbial Agent: Hepatitis A virus (HAV) — Sources of Agent Can manifest itself in water (and food)

Microbiology of Soil: A study of the microorganisms in soil, their functions, and the effect of their activities on the character of the soil and the growth and health of plant life.

Soil-related bacterial infections: Tetanus (caused by the toxin-producing, anaerobic, spore-bearing, Gram-positive bacteria Clostridium tetani); Botulism (caused by the toxin-producing, anaerobic, spore-bearing, Gram-positive bacteria Clostridium botulinum); Wound infections; Gastroenteritis (Clostridium perfringens is ubiquitous in soil, from which it is ingested into GIT.

It is associated with a variety of human diseases including classic food poisoning. Evidence suggests that most cases of gastrointestinal disease caused by C. perfringens have their source from food contaminated by other humans or by animal feces rather than directly from the soil).

Microbiology of Air: Airborne microorganisms: Airborne particles are a major cause of respiratory ailments of humans, causing allergies, asthma, and pathogenic infections of the respiratory tract. Airborne fungal spores are also important agents of plant disease, and the means for dissemination of many common saprotrophic (saprophytic) fungi. During a sneeze, millions of tiny droplets of water and mucus are expelled at about 200 miles per hour (100 metres per second). The droplets initially are about 10-100 micrometres diameter, but they dry rapidly to droplet nuclei of 1-4 micrometres, containing virus particles or bacteria. This is a major means of transmission of several diseases of humans as shown in the following slides.

Some important diseases of humans transmitted from person to person by inhaled airborne particles Virus diseases (virus type in brackets) Bacterial diseases (bacterial name in brackets) Chickenpox (Varicella) Whooping cough (Bordetella pertussis) Flu (Influenza) Meningitis (Neisseria species) Measles (Rubeola) Diphtheria (Corynebacterium diphtheriae) German measles (Rubella) Pneumonia (Mycoplasma pneumoniae, Streptococcus species) Mumps (Mumps) Tuberculosis (Mycobacterium tuberculosis) Smallpox (Variola)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Lecture 3

Food poisoning. Foodborne diseases. Chemical food poisoning.

 

Food poisoning is any illness resulting from the ingestion of food or drink contaminated with: living bacteria or their toxins, Inorganic chemical substances, poisons from plants & animals.

The term “food poisoning” means poisoning caused to consumer by consumption of food laden with microorganisms.

Types of food poisoning. There are two types of food poisoning: A.) Bacterial Food poisoning; B.) Non- Bacterial Food poisoning.

It is used very loosely to include both illnesses caused by the ingestion of toxins elaborated by microorganisms and those resulting from infection of the host through the intestinal tract. Generally food poisoning occurs when people consume food containing a toxin made by a microorganism. A bacterial food intoxication therefore refers to food borne illnesses caused by the presence of bacterial toxin(s) formed in food by bacteria in food(s). A bacterial food infection refers to food borne illnesses caused by the entrance of bacteria into the body through ingestion of contaminated foods and the reaction of the body to their presence or to their metabolites.

There are several kinds of food poisoning caused by microorganisms, the most familiar examples are botulism caused by toxins of Clostridium botulinum and staphylococcal food poisoning due toxins produced by Staphylococcus aureus. Staphylococcal food poisoning is one of the most common. The most dreaded food poisoning is botulism, because of the deadly toxin produced by the causative agent. Careless storage or handling of food can cause very unpleasant and sometimes dangerous symptoms.

Food is essential for every human being for life and its contamination or infection and subsequent manifestation of diseases through food is the well known phenomenon in humanhealth. The food borne diseases either by food infection or intoxication can be generally grouped as given below based on the causative agent and its manifestation into a disease.

 

Therefore, the bacterial food poisoningis caused in results of food infection andfood intoxication.

Food infection refers to the presence of bacteria or other microbes which infect the body after consumption.

Food intoxication refers to the ingestion of toxins contained within the food, including bacterially produced exotoxins.

B. Non- Bacterial Food poisoning By chemicals: Arsenic, Cu sulphate, Mercury, Cadmium, Pesticides, Sea foods, Certain plants, Fertilizers.

CAUSES: improper handling, preparationor food storage.

 

During its production Growing, Harvesting, Processing, Storing, Shipping or Preparinglarge variety of toxins that affect the environment: chemicals, pesticides or medicines in food and naturally toxic substances like poisonous mushrooms.

Good hygiene practices before, during & after food preparation can reduce the chances of contracting an illness.

 

Foodborn illnesses occurs after: 1- Ingestion of food contaminated with chemical toxin, 2- Ingestion of food contaminated with bacterial pathogens and/or their toxins.

The symptoms normally include abdominal pain, diarrhoea, nausea, vomiting and fever.

 

What is the difference between food infection and food poisoning?

Food borne diseases can be divided into food infection and food poisoning. The popular media tends to describe all food-related illnesses as "food poisoning", but strictly speaking, this is incorrect. Food poisoning is caused by consuming foods that contain toxins. These toxins can be produced by micro organisms, can occur naturally in the food (for example, in certain mushrooms) or can be a contaminant. Toxins directly affect the biological reactions taking place in the body. At sufficiently high concentrations, the effects are acute and take place a few hours after consumption.

Types of Bacteria. There are two types of bacteria that cause major problems in the food industry: Spoilage bacteria - responsible for the decomposition of food, Pathogenic bacteria - responsible for causing illness such as dysentery, typhoid and food poisoning.

 

Bacterial Food Borne Infections:

1) food poisoning caused by bacterial toxins:

Staphylococcus Aureus

Bacillus Cerus

Clostridium perfringens

Clostridium botulinum

 

2) foodborn illnesses caused by bacterial infection

Salmonella

E. Coli

Shigella spp.

Camplobacter jejuni

Listeria

Yersinia enterocolitis

 

Food Borne Infections cont. Mycotic food borne infections include Candida spp., Sporothrix spp., Wangiella spp.etc),

Viral food borne infections include hepatitis A, Norwak virus and poliomyelitis virus

 

The toxins can have various origins, but the two most well known bacterial toxins are produced by Staphylococcus aureus and Clostridium botulinum. Certain toxins e.g. mycotoxins have serious long-term effects even at small concentrations.Most of these toxins are resistant to heat, so they are not eliminated by cooking.A food borne infection is caused by an infectious pathogens (micro organisms that cause infections) in the food. These micro organisms multiply in the intestine. Furthermore these micro organisms release toxins that invade and damage the epithelium cells. The consequences are stomach ache and diarrhoea within some hours or several days after eating the contaminated food. After a few days these symptoms disappear, but one can still excrete the germ with the stools. Such a person is called a healthy carrier. By bad (toilet) hygiene one can contaminate food and other people. The bacteria causing most food infections are Salmonella , Campylobacter and E. coli. Viruses also cause food borne infections. Most food borne infections occur during the summer, because the growing conditions for the bacteria are better. In most cases the food infection is quite mild, most people only have diarrhoea. Older people, small children or people with a weak resistance are most severely affected. 
Proper heating of food can prevent food borne infections. Almost all non-spore forming bacteria are killed at temperatures above 70 °C. Although most food borne infections occur in the home, outbreaks in restaurants often get more attention because they tend to affect larger numbers of people.

 

Food borne diseases:

Poisonings Infections

Chemical Intoxications Enterotoxigenic Invasive

Poisonings

Sporulation Growth and lysis

Poisonous Microbial plant tissues animal tissue intoxication

Intestinal Systemic Other _ mucosa tissues

Algal Mycotoxins

Bacterial toxins

toxins Muscle Liver

Enterotoxins Neurotoxins Interferes with carbohydrate metabolism.

 

Human illnesses caused by foodborne microorganisms are popularly referred to as food poisoning. The common use of a single classification is due primarily to similarities of symptoms of various food-related diseases (see Table 1). Apart from illness due to food allergy or food sensitivity, foodborne illness may be divided into two major classes, food infection and food intoxication. Food infection results when foods contaminated with pathogenic, invasive, food poisoning bacteria are eaten. These bacteria then proliferate in the human body and eventually cause illness. Food intoxication follows the ingestion of preformed toxic substances which accumulate during the growth of certain bacterial types in foods.

The period of time between the consumption of contaminated foods and the appearance of illness is called the incubation period. The incubation period can range anywhere from less than one hour to more than three days, depending on the causative organisms or the toxic product.

 

 

Table 1. Characteristics of the important bacterial food intoxications and foodborne infections. (NAS-NRC, 1975)*

 

Disease

EtiologicAgent

IncubationPeriod

Symptons

Botulism

Clostridium botulinum A.B.E.F toxin

Usually 1 to 2 days; range 12 hours to more than 1 week

Difficulty in swalling, double vision, difficulty in speech. Occasionally nausea, vomiting, and diarrhea in early stages. Constipation and subnormal temperature. Respiration becomes difficult, often followed by death from paralysis of muscles of respiration.

Staphylococcal food poisoning

Staphyloccal enterotoxin

1 to 6 hours; average 3 hours

Nausea, vomiting, abdominal cramps, diarrhea, and acute prostration. Temperature subnormal during acute attack, may be elevated later. Rapid recovery-usually within 1 day.

Salmonellosis

Specific infection by Salmonella spp.

Average about 18 hours; range 7 to 72 hours

Abdominal pains, diarrhea, chills, fever, frequent vomiting, prostration. Duration of illness: 1 day to 1 week.

Shigellosis (bacillary dysentery)

Shigellasonnei, s. flexneri, s. dysenteriae, s. boydii

Usually 24 to 48 hours; range 7 to 48 hours

Abdominal cramps, fever, chills, diarrhea, watery stool (frequently containing blood, mucus, or pus), spasm, headache, nausea, dehydration, prostration. Duration: a few days.

Enteropathogenic Escherichia coliinfection

Escherichia coliserotypes associated with infant and adult infections

Usually 10 to 12 hours; range 5 to 48 hours

Headache, malaise, fever, chills, diarrhea, vomiting, abdominal pain. Duration: a few days.

Clostridium perfringens foodpoisoning

Clostridium perfringens

Usually 10 to 12 hours; range 8 to 22 hours

Abdominal cramps and diarrhea, nausea, and malaise, vomiting very rare. Meat and poultry products usually involved. Rapid Recovery.

Bacillus cereus food poisoning

Bacilluscereus

Usually about 12 hours; range about 8 to 16 hours

Similar to Clostridium perfringens poisoning

Vibrio Parahaemolyticus food poisoning

Vibrio Parahaemolyticus

Usually 12 to 14 hours; range 2 to 48 hours

Abdominal pain, server watery diarrhea, usually nausea and vomiting, mild fever, chills and headache. Duration: 2 to 5 days.

*Repeated from Prevention of Microbial and Parasitic Hazards Associated with Processed Foods, pages 6-7, with the permission of the National Academy of Sciences, Washington, DC.

 

NON-INFECTIOUS CAUSES OF FOOD POISONING.

Legumes and beans produce oxidants which are toxic to people with glucose-6-phosphate dehydrogenase (G6PD) deficiency Consumption produces headache, nausea and fever progressing to severe haemolysis, haemoglobinuria and jaundice (favism).

Many fungal species induce a combination of gastroenteritis and cholinergic symptoms of blurred vision, salivation, sweating and diarrhoea.

Amanita phalloides (death head mushroom) causes acute abdominal cramps and diarrhoea followed by hepatorenal failure, often fatal.

Chemical food poisoning could be due to cyanide, arsenic, lead or any other poisonous chemical on their entry into the body. Poisoning due to plant tissues could be due to harmful substances present in plants and plant materials. Animal tissue poisoning could be due to tissues like skin of lizards other harmful parts animals. Microbial intoxication is by different microbial toxins produced by variety of microorganisms. Some of the algal toxins are like hepatotoxic microcystin by Microcystis aeruginosa, neurotoxic anatoxin A,B,C or D by Anabaena flosaquae.

Chemical toxins:

-Paralytic shellfish toxin

Consumption produces gastrointestinal symptoms within 30 minutes, followed by respiratory paralysis.

-Warm-water coral reef fish

Consumption produces gastrointestinal symptoms 1-6 hours later with associated paraesthesiae of the lips and extremities, distorted temperature sensation, myalgia and progressive flaccid paralysis.

The gastrointestinal symptoms resolve rapidly but the neuropathic features may persist for months.

-Scombrotoxic fish poisoning

Consumption produces symptoms within minutes with flushing, burning, sweating, urticaria, pruritus, headache, colic, nausea and vomiting, diarrhoea, bronchospasm and hypotension.

Management is with salbutamol and antihistamines.

-Thallium and cadmium

can cause acute vomiting and diarrhoea resembling staphylococcal enterotoxin poisoning.

Fungal toxins or mycotoxins are highly toxic and are generally mutagenic, carcinogenic and teratogenic. Some mycotoxins are aflatoxins produced by Aspergillus flavus, patulin by Penicillium expansum and ochratoxin by Aspergillus ochraceus. Various bacteria are known to produce variety of toxins which are responsible for bacterial disease manifestation. Some of theimportant bacterial food borne diseases are given in the following paragraphs.

Food borne infections can be classified into two categories based on the criteria whether the food serves to carry microbes or culture them. (i) Those infections in which the food does notsupport growth of pathogens but merely carries them like in case of diphtheria, tuberculosis, infectious hepatitis etc. (ii) Those in which the food serves as a culture medium for growth ofpathogens like in case of infections by Salmonella, Vibrio parahaemolyticus, enteropathogenic E. coli etc.

High risk foods. Some foods are high-risk, as they provide the ideal conditions needed for micro-organisms to grow.

   These include: meat and meat products; milk and dairy products; fruit.

   If these foods become contaminated with food-poisoning micro-organisms and conditions allow them to multiply, the risk of food-poisoning increases.

 

Learning objectives:

To recognise the seriousness of food poisoning.

To identify high risk foods

To identify people at risk of food poisoning.

To identify factors affecting food poisoning.

To identify methods of shopping safely to prevent food poisoning.

To recognise common bacteria involved in food poisoning.

 

 

 

 

 

 

 

 

Lecture 4

   Microorganisms and food production.

Sanitary and microbiological testing of food products.

 

What are microorganisms? Microbes: Friend & Foe. Microbes are sub- microscopic organisms so tiny that millions can fit into the eye of a needle. They are the oldest form of life on earth. Most microorganisms are harmless to humans. You swallow millions of microbes everyday with no ill-effects. In fact we are dependent on microbes to help us digest our food.

Beneficial Microbes. Microbes serve many useful purposes to humans. We use them inside our bodies with natural digestion processes. We also use them in industry and food production, like dairy products. Food like cheese, pickles, chocolate, bread, wine, beer and soy sauce are all made with the help of different types of bacteria and yeast. In most of these food products, bacteria play a major role because they produce lactic acid. Fermentation of food is commonly used to process food for making alcoholic beverages, leavening of bread and preserving foods.

Food fermentation. Fermentation is used in the food and beverage industry to convert carbohydrates into alcohol, carbon dioxide and organic acids (i.e. lactic acid and acetic acid). The fermentation process often takes place in an anaerobic environment – which means no oxygen is present. Microorganisms are important in the food industry, not only as producers of certain foods but as contaminants of others.

The manufacture involves a microbial process by which the milk sugar, lactose is converted to lactic acid.

As the acid accumulates, the structure of the milk protein changes (curdling) and thus the texture of the product.

Lactic acid also gives fermented milks their slightly tart taste. Additional characteristic flavours and aromas are often the result of other products of lactic acid bacteria. For example acetaldehyde, provides the characteristic aroma of yoghurt, while diacetyl imparts a buttery taste to other fermented milks.

Additional micro-organisms such as yeasts can also be included in the culture to provide unique tastes. For example, alcohol and carbon dioxide produced by yeasts contribute to the refreshing, frothy taste of kefir, koumiss and leben.

Other manufacturing techniques such as removing the whey or adding flavours, also contribute to the large variety of available products.

The yeast of the Zygosaccharomyces genus have had a long history as spoilage yeasts within the food industry.

In the food processing industry, carefully cultured yeasts are used in the production of beer, wine and bread.

The most common yeast associated with winemaking is Saccharomyces cerevisiae which has been favored due to its predictable and vigorous fermentation capabilities, tolerance of relatively high levels of alcohol and sulfur dioxide as well as its ability to thrive in normal wine pH between 2.8 and 4.

Molds: However, some molds are beneficial and are used in the production of antibiotics such as penicillin and in soy sauce production. Molds are specifically grown to create blue cheeses such as Roquefort and stilton and that which grows on the rind of camembert providing distinct flavors. Molds are essential components of several food products, such as some cheeses, sausages and soy sauce.

Pharmaceuticals from molds. Alexander Fleming's accidental discovery of the antibiotic penicillin involved the mold Penicillium, although the species identity is disputed (Penicillium notatum, Penicillium chrysogenum or Penicillium rubens).

Several of the statin cholesterol-lowering drugs (such as Lovastatin, from Aspergillus terreus) are derived from molds.

Cheese making. Three main types of cheese rely on molds for their characteristic properties: blue cheese, soft ripened cheese and rind-washed cheese.

To make blue cheese, the cheese is treated with a mold, usually Penicilliumroqueforti, while it is still in the loosely pressed curd form. As the cheese matures, the mold grows, creating blue veins within it which gives the cheese its characteristic flavour. Examples include Stilton, Roquefort and Gorgonzola.

Soft ripened cheese such as Brie and Camembert are made by allowing Penicillium camemberti to grow on the outside of the cheese, which causes them to age from the outside in. The mold forms a soft white crust, and the interior becomes runny with a strong flavour.

Molds in Meat fermentation. A wide variety of molds (i.e. Penicilliumchrysogenum and Penicilliumnalgiovense) are used to ripen surfaces of sausages. The mold cultures plays a role in aroma formation and improve the texture of the sausages. They also contribute to shortening of the ripening period and preserving the natural quality and in that way expanding the shelf life of the meat product.Inoculations of sausages with molds were traditionally done with the indigenous flora of the slaughters, the so called house flora.

Soy sauce.Traditional soy sauce is made by mixing soybeans and other grains with a mold – either Aspergillus oryzae or Aspergillus sojae– and yeast. Historically, this would have been left to ferment in the sun, but nowadays it is mostly made under industrial conditions. The key flavour ingredients formed in this process are salts of the amino acid glutamic acid, notably monosodium glutamate.

We need microbes for our survival and maintaining good health. In fact, there are “good” and “bad” microbes. The good ones fight viruses and infections, break down fibers, harvest calories and nutrients, and strengthen our immune systems. But also there are “bad” microbes that threaten our survival by causing obesity, diabetes, inflammatory bowel disease, allergies, accelerated aging, and even depression. "There is a constant war going on between good and bad microbes in each of us. Winning the microbe war is essential to our well-being – in fact, to our very lives,“according to the current research.

Probiotics. Probiotics are micro-organisms that have claimed health benefits when consumed. Probiotics are bacteria that are similar to beneficial micro-organisms that naturally live in our digestive system. There are two basic groups, Lactobacillus and Bifidobacterium, which are further divided into species and strains. Lactic acid bacteria (LAB) and bifidobacteria are the most common types of microbes used as probiotics, but certain yeasts and bacilli may also be used. Probiotics are commonly consumed as part of fermented foods with specially added active live cultures, such as in yogurt, soy yogurt, or as dietary supplements.

Factors relevant in considering the representativeness of a sample include:

-the homogeneity of the food, the relative sizes of the sample to be taken and the whole,

-the potential degree of variation of the parameter(s) in question through the whole,

-and the significance and intended use of the analytical result.

Testing and Methods of Analysis. To ensure food safety and quality, food samples require certain tests and analyses. The following tests and analyses can be conducted:

1. Food allergen testing

2. Food chemical analysis

3. Food contact tests

4. Food contaminant testing

5. Nutritional analysis and testing

6. GMO testing

7. Melamine contamination testing

8. Microbiological tests

9. Spiral plating for bacterial count

10. Pesticide residue testing

11. Veterinary drug residue testing

12. PCR food testing

 

Detection of Food-Borne Pathogens must be rapid and sensitivemethods include:

culture techniques – may be too slow

immunological techniques - very sensitive

molecular techniques

probes used to detect specific DNA or RNA

sensitive and specific

With many animal drug residues strictly regulated to protect consumer health, to develop best testing practices and to offer rigorous veterinary drug residues screening it is particularly important as legislative requirements become more stringent, both in terms of the range of substances covered and the lower residue levels permitted.

To support the identification and control that is vital to products’ compliance, test for drug residues is done using the following:

Liquid chromatography–mass spectrometer coupled (LC/MS-MS)

High performance liquid chromatography with post column fluorescence derivatisation (HPLC-FLD)

High performance liquid chromatography with ultraviolet spectrophotometer (HPLC-UV).

Consequently, test and method developers must take these expectations into consideration when establishing sampling plans and interpretations of the results. So, in a practical sense, specifications should identify:

-The product to be tested

-The frequency of testing (e.g., every fifth lot shipped to Customer)

-The sample size and how the sample is to be collected (e.g., a 125 g composite of five 25 g samples collected from the beginning, middle and end of the production run)

-The target organism

-Test method

-Acceptance criteria (examples: “not to exceed 106 cfu/g aerobic plate count”, “not to exceed 1000 cfu/g yeast and mold”, or “no detectable Salmonella or E. coli O157:H7 in 25 g”)

-Actions to be taken in the event that the acceptance criteria are exceeded.

 

Food safety is a shared responsibility and it is up to everyone — government, food manufacturers, retailers, farmers, and of course, consumers — to take an active role in safe food handling.

Food safety is an integral part of the production of all foods and the shared responsibility of all segments of the supply chain. In recent times there has been increased awareness for the need to evaluate the food safety practices in the production of agricultural products. Consumer demands for fresh and convenient forms of produce have led to the development of “Field to Fork” food safety practices in the fresh produce industry. The use of a microbiological testing program is one tool that may be used in the development and verification of a food safety program.

 

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