Biological Sciences
Food Bacteria
Food bacteria are microorganisms that can be found in various types of food. While some food bacteria are beneficial and used in processes like fermentation, others can cause food spoilage or foodborne illnesses. Proper food handling, storage, and cooking techniques are important for preventing the growth and spread of harmful food bacteria.
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12 Key excerpts on "Food Bacteria"
eBook - PDF- Orolugbagbe, Gboyega(Authors)
- 2018(Publication Date)
- Agri Horti Press(Publisher)
Chapter 16 Food Microbiology Food microbiology is the study of the microorganisms that inhabit, create, or contaminate food. Including the study of microorganisms causing food spoilage. [1] “Good” bacteria, however, such as probiotics, are becoming increasingly important in food science. In addition, microorganisms are essential for the production of foods such as cheese, yogurt, other fermented foods, bread, beer and wine. Microorganisms are tiny, mostly one-celled organisms capable of rapid reproduction under proper growth conditions. Those microorganisms important in the food industry include the bacteria, viruses, yeasts, molds, and protozoans. Many are helpful and serve useful functions such as causing breads to rise, fermenting sugars to alcohol, assisting in the production of cheese from milk, and decaying organic matter to replenish nutrients in the soil. Microorganisms can also cause foods to spoil and make them inedible. Spoilage organisms cost the food industry millions of dollars each year. Microorganisms can also be harmful. These are called pathogens and cause between 24 to 81 million cases of foodborne illness in the U.S. each year. These forms of life, some so small that 25,000 of them placed end to end would not span one inch, were little known until the last century. Antony van Leeuwenhoek and others discovered “very little animalcules’ in rain water viewed through crude microscopes. We now know that microorganisms occur everywhere on the skin, in the air, in the soil, and on nearly all objects. It was not until Pasteur proved that microorganisms could be eliminated from a system, such as a can of food, and sealed out (hermetically sealed), that man could exert control over the microbes in his environment. This ebook is exclusively for this university only. Cannot be resold/distributed. Food Microbiology 197 BACTERIA Bacteria are the most important microorganisms to the food processor.
eBook - PDF- Navnidhi Chhikara, Anil Panghal, Gaurav Chaudhary, Navnidhi Chhikara, Anil Panghal, Gaurav Chaudhary(Authors)
- 2023(Publication Date)
- Wiley-Scrivener(Publisher)
1 Navnidhi Chhikara, Anil Panghal and Gaurav Chaudhary (eds.) Microbes in the Food Industry, (1–38) © 2023 Scrivener Publishing LLC 1 Food Microbiology: Fundamentals and Techniques Raina Jain, Prashant Bagade*, Kalpana Patil-Doke and Ganesh Ramamurthi National Commodities Management Services Limited, Hyderabad, India Abstract Food microbiology is a broad subject encompassing study of both beneficial and harmful microorganisms in food, and their effects on the quality and safety of food. Beneficial microbes present in food offer an array of health benefits to humans and are important sources for fermentation, probiotics and bio-preservatives. Contrarily, harmful bacteria lead to food spoilage and a countless number of foodborne dis- eases which may even prove to be lethal, if uncontrolled. Food microbiology uses a number of testing methods to detect, enumerate and identify the microorganisms present in food. Conventionally, it involved culturing of microbes on suitable media and analyzing the results on the basis of physical or biochemical tests. However, such techniques are time-consuming and laborious. As a result, rapid and high-through- put techniques with use of advanced equipment and strategies have been developed to ensure quality and safety of food in real time. The chapter presents the long his- tory of the development of Food Microbiology as a subject, along with classical and advanced techniques used to identify and quantitate foodborne microorganisms. Keywords: Food microbiology, food spoilage, food microbes, food regulations, microbiological techniques, probiotics, AI and ML in food, biosensors 1.1 Introduction Food microbiology is the study of microorganisms that colonize, modify, process or spoil food. It deals with foods and beverages of diverse compo- sition, combining a broad spectrum of environmental factors, which may *Corresponding author: [email protected] 2 Microbes in the Food Industry influence microbial survival and growth.
eBook - ePubFood Plant Sanitation
Design, Maintenance, and Good Manufacturing Practices
- Michael M. Cramer(Author)
- 2022(Publication Date)
- CRC Press(Publisher)
Chapter 3 Microorganisms of Food Manufacturing Concern DOI: 10.1201/9780429294341-3 If it don’t stink, stuff it! —Anonymous food plant employee They go by many names: germs, bacteria, microorganisms, microbes, even “bugs.” They have been the main focus of several Hollywood movies, including The Andromeda Strain and Outbreak. In The War of the Worlds by H. G. Wells, they were responsible for saving the human race because Martian invaders had no resistance to bacteria that man had been accustomed to for millennia. Microorganisms have been on Earth for millions of years, longer than man. Microorganisms Microorganisms are biological entities, and they can be a benefit or a potential hazard to humans and to the food manufacturing industry. Bacteria represent the largest group of microorganisms [ 1 ]. Most bacteria are harmless; in fact, some provide benefits to humans by protecting the skin and nasal passages and also aid in the digestion process. Some also benefit the food industry when they are used for the production of cultured items such as cheese, yogurt, and fermented sausage. However, they can pose a threat to humans and to the industry when they result in foodborne illness and food spoilage. Microbiological contamination of food may result in product spoilage, reduction in shelf life, or foodborne illness. It is important to understand food-related microorganisms, with regard to growth needs and environmental requirements to better understand their control mechanisms. Fortunately, the food industry has evolved from the dinosaurs who truly believed that if something does not stink, it is OK to stuff to a more science-based understanding of microorganisms that impact the food industry. The common microorganisms that will be reviewed in this chapter, as they relate to foods, are indicator organisms, spoilage organisms, and pathogens
eBook - ePub- Bibek Ray, Arun Bhunia(Authors)
- 2013(Publication Date)
- CRC Press(Publisher)
Specific methods were developed for their isolation and identification. The importance of sanitation in the handling of food to reduce contamination by microorganisms was recognized. Specific methods were studied to prevent growth as well as to destroy the spoilage and pathogenic bacteria. There was also some interest in isolating beneficial bacteria associated with food fermentation, especially dairy fermentation, and studying their characteristics. However, after the 1950s, food microbiology entered a new era. Availability of basic information on the physiological, biochemical, and biological characteristics of diverse types of food; microbial interactions in food environments; and microbial physiology, biochemistry, genetics, and immunology has helped open new frontiers in food microbiology. 1, 6, 7, 8, 9, 10 Now, understanding the microbial community and microbial interaction in a complex food environment through microbiome analysis, whole genome sequencing, and development of novel and natural intervention technologies are at the forefront of food microbiology. Food Fermentation/Probiotics Development of strains with desirable metabolic activities by genetic transfer among strains Development of bacteriophage-resistant lactic acid bacteria Metabolic engineering of strains for overproduction of desirable metabolites Development of methods to use lactic acid bacteria to deliver biologically relevant proteins or vaccines Sequencing genomes of important lactic acid bacteria and bacteriophages for better understanding of their characteristics Food biopreservation with desirable bacteria and their antimicrobial metabolites Understanding of important characteristics of probiotic bacteria and development of desirable strains Effective methods to produce starter cultures for direct use in food processing Bioengineered probiotics for health promotion and disease control Food
eBook - PDF- Abeer Iqbal(Author)
- 2020(Publication Date)
- Delve Publishing(Publisher)
Figure 1.1. Food microbiology identification systems. Source: https://www.researchgate.net/figure/FCM-and-Potential-Applications-in-Food-Microbiology-Food-Fermentations-Source-Doolan_fig1_315697351. Regardless of these earlier observations, the works of torchbearers like Pasteur and Koch in the nineteenth century seem to have highlighted microbiology as a scientific discipline. The attention of Pasteur, Koch, and all the following forerunners was not based on what they are but on what Introduction to Food Microbiology 3 these microorganisms do. Pasteur, for instance, (Debré, 1994), experimented extensively on fermented food products like vinegar, wine, and beer clarifying how wavering from the common fermentation pattern can lead to disorders in the end-product (Ross, 1996; Baranyi and Roberts, 1995; Sivapalasingam et al., 2004). Food microbiology analyses the approaches through which food affects people because of microbial activity, it also has an immense economic and practical significance which cannot be ignored (Figure 1.2). Figure 1.2. Microbiology lab at NASA. Source: https://www.nasa.gov/feature/microbiology . Presently, the living world is divided into three primary disciples based on the distinctions in cell types: the Eukarya, the Bacteria, and the Archaea. Every disciple contains microbes that interest food microbiologists. Even though members of the bacterial group dominate naturally, the Eukarya and fungi (yeasts and molds) are essential in several areas like mycotoxins, fermentation, and spoilage (Betts, 1995; Beuchat et al., 1998; Scallan et al., 2011). In case of intense halophilic bacteria (Archea) that are capable of greatly spoiling salted products and may be responsible for the production of goods such as the fish sauces of Southeast Asia, Archaea are of little importance in food. The primary characteristics of different groups of cellular microorganisms have been explained in Table 1.1.
- Sanjay Kumar, Narendra Kumar, Shahid Ul Islam, Shahid Ul-Islam(Authors)
- 2022(Publication Date)
- Wiley-Scrivener(Publisher)
Food processing and preservation using microorganisms have been common for decades. Microbes are employed at various stages of postharvest operations such as ripening, fermentation, etc. Microbes render taste, texture, and smell to the foods and produce certain inhibitory compounds that aid in food preservation. These organisms are also employed to develop functional and novel foods such as cheese, yogurt, prebiotics, and probiotics. A wide range of foods and beverages are produced with the help of microbial actions. The application of microorganisms in food processing and preservation is a slow process built on natural processes and experimentation observations. This chapter summarizes the applications of microbes in different food industries.3.2 Microflora of Food Products
3.2.1 Bacteria
Bacteria are unicellular prokaryotes and are present almost everywhere in different shapes, sizes, and arrangements like coccus (spherical), bacillus (rod-shaped), vibrio (comma-shaped), and spirilla (spiral). Bacteria can be classified based on the cell wall composition as gram-positive bacteria containing peptidoglycans and gram-negative bacteria containing lipopolysaccharide in the cell wall. It can also be classified based on the mode of nutrition as autotrophs or heterotrophs and based on respiration as aerobic or anaerobic bacteria. Bacteria are beneficial for food industries in several ways. Several strains of bacteria such as Lactobacillus, Streptococcus, Bifidobacterium, Erwinia, etc., have been utilized extensively to produce different types of food products such as fermented food and alcoholic beverages.3.2.2 Yeast
Yeast is a unicellular fungus, and it can convert sugar into carbon dioxide and ethanol. It has been in wide use in the food industry to produce baked products and make alcoholic beverages. There is evidence of its use in bread making in ancient Egyptians. Yeast species Saccharomyces cerevisiae has been used extensively in the food industry. It is commonly known as baker’s yeast used in bakery products and brewer’s yeast used in beverage production. Yeast is produced industrially in a different form for its specific application. Yeast is grown by the aerobic fermentation process in a large tank on sugar-rich substrates like molasses. They are collected from the tank and concentrated by centrifugation. After that, they are processed and available in different forms like freeze-dried powder, active dried granules, and vacuum-packed fine powder. Some of the commonly used yeast species of the food industry are Saccharomyces carlsbergensis, Kluyveromyces marxianus, Brettanomyces, Yarrowia lipolytica Zygosaccharomyces, Cryptococcus, Galactomyces candidus, Debaryomyces hansenii,
eBook - PDFDairy Microbiology
A Practical Approach
- Photis Papademas(Author)
- 2014(Publication Date)
- CRC Press(Publisher)
In most cases food-borne diseases are associated with diarrhoea, vomiting, other gastrointestinal and/or extra intestinal manifestations, but secondary complications can occur. Managing the microbiological food safety risk with the goal of reducing the burden of microbial food-borne illnesses is still one of the important challenges today due to the fact that factors affecting the microbiological food safety are changing dramatically. Over time we have been witnessed to rapid and huge technological changes in food processing and production procedures and also due to the changes in methods of microbiological analysis. Microbiological criteria are tools that can be used in assessing the safety and quality of foods. They are necessary to assist in setting critical limits in Basic Concepts of Food Microbiology 11 HACCP systems, verification and validation of HACCP procedures, other hygiene control measures and in shelf life studies where storage trials and challenge tests are needed (Institute of Food and Science Technology, Professional Food Microbiology Group 1997). In microbiological risk assessments, knowledge of microbial population distribution and numbers in food forms an essential part of the information required, in conjunction with population exposure, infective dose and pathogenicity of organisms. When mathematical models are used to predict microbial growth, survival or decline, it is also necessary to appreciate the number that are inevitable and those that cause concern or signal the end of shelf life (Institute of Food and Science Technology, Professional Food Microbiology Group 1997). Microbiological criteria not only give guidance, but also set microbiological criteria defining the acceptability of the processes and for setting a limit above which a foodstuff should be considered unacceptably contaminated with the microorganisms for which the criteria are set (EC 2005).
eBook - PDF- Martin Adams, Maurice Moss(Authors)
- 2007(Publication Date)
- Royal Society of Chemistry(Publisher)
3.5 PREDICTIVE FOOD MICROBIOLOGY Understanding how different properties of a food, its environment and its history can in¯uence the micro¯ora that develops on storage is an important ®rst step towards being able to make predictions concerning shelf-life, spoilage and safety. The food industry is continually creating new microbial habitats, either by design in developing new products and reformulating traditional ones, or by chance, as a result of deviations in the composition of raw materials or in a production process. To be able to predict microbial behaviour in each new situation and determine its consequences for food safety and quality, we must ®rst describe accurately the food environment and then determine how this will affect microbial growth and survival. Characterization of a habitat in terms of its chemical and physical properties is generally straightforward, although problems can arise if a property is not uniformly distributed throughout the product. This can be a particular problem with solid foods, for example the local salt 54 Factors Affecting the Growth and Survival of Micro-organisms in Foods concentration may vary considerably within a ham or a block of cheese and we have seen in Section 3.3.1 how water can migrate through a mass of food. A considerable amount of data is available on how factors such as pH, a w , and temperature affect the growth and survival of micro-organisms and some of this was described in Sections 3.2 and 3.3. Much of this information was however acquired when only one or two factors had been changed and all the others were optimal or near-optimal. In many foods a very different situation applies, micro-organisms experi-ence a whole battery of sub-optimal factors which collectively determine the food's characteristics as a medium for microbial growth.
eBook - ePub- Stephen J. Forsythe(Author)
- 2019(Publication Date)
- Wiley-Blackwell(Publisher)
A probiotic was initially defined as ‘a live microbial food supplement which beneficially affects the host animal by improving its intestinal microbial balance’ (Fuller 1989). This definition was broadened by Havenaar and Huis in't Veld (1992) to a ‘mono‐ or mixed‐culture of live microorganisms which benefits man or animals by improving the properties of the indigenous microflora’. The Lactic Acid Bacteria Industrial Platform workshop proposes a different definition for probiotics as ‘oral probiotics are living microorganisms, which upon ingestion in certain numbers, exert health benefits beyond inherent basic nutrition’ (Schaafsma 1996). This definition means that probiotics may be consumed either as a food component or as a non‐food preparation (Guarner and Schaafsma 1998). Synbiotics can be described as ‘a mixture of probiotics and prebiotics that beneficially affects the host by improving the survival and implantation of live microbial dietary supplements in the gastrointestinal tract’ (Gibson and Roberfroid 1995). A variety of probiotic foods have been developed and marketed. They can be divided into the following categories: Conventional fermented foods that are consumed primarily for nutritional purposes. Food supplements and fermented milk with food formulations that are used to deliver probiotic bacteria. Dietary supplements, which are in the form of capsules and other formulations. These products usually contain members either of the Lactobacillus and/or Bifidobacterium genera. As such these cultures are accepted to be safe for consumption due to their long history of use in conventional fermented foods. The idea of using lactic acid bacteria as an aid to improved health is not new: see Section 3.7 on fermented foods for related stories. However, the current trend is largely driven by consumer demands rather than scientific investigation
eBook - ePubUnderstanding Microbes
An Introduction to a Small World
- Jeremy W. Dale(Author)
- 2012(Publication Date)
- Wiley-Blackwell(Publisher)
5 Microbes and Food – Friend and Foe In previous chapters, we saw how bacteria can help to prevent infection as well as causing it. When it comes to the food we eat, the many-sided behaviour of microbes becomes even more marked. Microbes in the food can make it go off, or they can make us ill. On the other hand, we use microbes extensively to preserve and produce food. In this chapter, I will look at some examples of these many facets of microbes in relation to the food we eat and drink. 5.1 Food Spoilage The concept of food ‘going off’ is a familiar one. Most fresh food will become spoiled, in one way or another, if kept too long or under the wrong conditions. It does not necessarily mean that it would make someone ill if they ate it; it would just be unpalatable. Let's look at some examples of how it happens. Raw milk from a healthy cow, taken under clean conditions, contains low numbers of bacteria (10 2 –10 3 per ml). However, milk is an excellent medium for growth of many bacteria and, if not kept cold, any organisms that are in the milk to start with (as well as others that contaminate the milk subsequently) will multiply and cause the milk to ‘go off’. Traditionally, milk went sour, which was due to acid production by lactic acid bacteria fermenting the lactose in the milk. This is now rarely seen, partly because pasteurization reduces the numbers of such bacteria, and partly because of refrigeration, since these bacteria will not grow at the low temperatures in a fridge. More commonly seen nowadays is the phenomenon known as ‘bitty cream’ – the milk may look good and may have not much of a smell but, when it is added to a hot drink, it forms particles on the surface. This is due mainly to Bacillus bacteria (which are very common all around us, and hence can readily contaminate the milk). These bacteria form spores which can survive the heat treatment of pasteurization, and some strains can grow, albeit slowly, at refrigeration temperatures
eBook - ePub- Sourish Bhattacharya, Heba Hassan Abd-El Azim Salama(Authors)
- 2023(Publication Date)
- Jenny Stanford Publishing(Publisher)
Chapter 1 Introduction to the Microbiological Spoilage of Foods and Beverages Ashraf Mahdy Sharoba Food Technology Department, Moshtohor Faculty of Agriculture, Banha University, Egypt [email protected]Food spoilage is a complex ecological phenomenon, caused mainly by the biochemical activity of specific groups of microorganisms. Microbiological spoilage of foods and beverages is the main cause of quality deterioration in these commodities. Microorganisms (i.e., bacteria, molds, and yeasts) associated with spoilage as well as factors affecting their growth and determining their eventual dominance in foods and beverages are presented. During harvesting, processing, and handling operations, food may become contaminated with a wide range of microorganisms. Subsequently, during distribution and storage, only a small fraction of these will develop and cause serious deterioration. Which microorganisms will develop is dependent upon food derived or environmental factors. The loss of food quality for the most important food commodities depends on the microbiological load. Food spoilage may be caused by a wide range of reactions including some that are mainly physical or chemical and others due to the action of enzymes or microorganisms. The primary factors associated with food spoilage are associated with intrinsic food properties and (cross) contamination during harvesting, slaughter, and processing in combination with temperature abuse. For fresh foods, the primary quality changes may be bacterial growth and metabolism resulting in possible pH changes and formation of toxic compounds, off-odors, gas, and slime formation. Despite the fact that food spoilage is a huge economical problem, it is obvious that the mechanisms and interactions leading to food spoilage are very poorly understood. In this chapter, we will deal with the most important causes of microbial corruption in food and beverages and the most important and most famous types of microbial corruption in food and beverages and the extent of the risk of these types of microorganisms to the quality of food products and the health of consumers in addition to discussing how to reduce or prevent the occurrence of microbial corruption in food and beverages.
eBook - PDF- Stephen J. Forsythe(Author)
- 2008(Publication Date)
- Wiley-Blackwell(Publisher)
As can (a) (b) (c) (d) Fig. 4.11 Biofilm formation. The Microbiology of Safe Food 140 be seen in Fig. 4.12, the adhered bacteria are covered with organic material (polysaccharide and food residues) which may inhibit the penetration of the disinfectant due to its lack of wetting properties. Therefore a detergent activity is required to remove this outer layer prior to disinfection. The dead microbial biomass must be removed otherwise it may act as a conditioning film and nutrient source for further biofilm formation. New cleaning agents and enzyme treatments are being for- mulated for the effective removal of biofilms. (a) (b) (c) (d) Fig. 4.12 Biofilm removal. The Microbial Flora of Food 141 5 FOOD POISONING MICROORGANISMS Food poisoning is caused by food which: (1) Looks normal (2) Smells normal (3) Tastes normal Because the consumer is unaware that there is a potential problem with the food, a significant amount is ingested which exceeds the infectious dose (Table 7.7, see also Table 9.1) and hence they become ill. Conse- quently it is hard to trace which food was the original cause of food poisoning since the consumer will not recall noticing anything appro- priate in their recent meals. Food poisoning is caused by a variety of organisms and the incubation period and duration of illness varies con- siderably (Table 5.1). Food poisoning organisms are normally divided into two groups: . Infections e.g. salmonella, campylobacter and pathogenic E. coli . Intoxications e.g. B. cereus, St. aureus, Cl. botulinum The first group comprises organisms which multiply in the human intestinal tract, whereas the second group comprises organisms that produce toxins either in the food or during passage in the intestinal tract. This division is very useful to help recognise the routes of food poisoning. Vegetative organisms are killed by heat treatment, whereas spores may survive and hence germinate if the food is not kept sufficiently hot or cold.
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