International Summit on Microbial Aspects on Food Spoilage and Quality November 29-30, 2019 Madrid, Spain

\r\n Accurate detection of viable bacteria in foods is critical and necessary in assessing the risk for foodborne outbreaks because only live pathogens constitute the risk of foodborne outbreaks. Currently, two techniques are available for viability detection of foodborne pathogens. The first one is based on the detection of mRNA by using reverse-transcriptase PCR (RT-PCR). The other technique for viable cell detection is an approach that uses PCR method in conjunction with biological dyes, ethidium mono azide (EMA) and propidium mono azide (PMA, a derivative of ethidium bromide).  Packaging is the cornerstone of the food processing industry. In fact, the processing and packaging industry transforms food from one stage to another based on appropriate techniques and methods, and the entire chain of events can be subsumed under this one phrase. As most packaging generates waste, there is renewed focus on creating sustainable packaging and some of the examples of those materials are polylactide acid (PLA) plastics, sugar cane pulp, fiber composite, starch-based films, modified atmosphere packaging (MAP), Smart packaging and so on. Bluetooth standards, wireless network, RFID technology, fieldbus technology, modular object-oriented DBMS, client-server-based distributed architecture, Human—Machine Interface and graphics, and user-friendly handheld devices play vital roles in a typical modern-day food processing plant.

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\r\n All food processing involves a combination of procedures to achieve the intended changes to the raw materials. These are conveniently categorised as unit operations, each of which has a specific, identifiable and predictable effect on a food. The main aim of novel food processing technologies is to reduce the damage to food caused by processing ie., texture, taste, flavor, aroma and colour. Heat processing is a major cause of changes to nutritional properties of foods. Oxidation is a second important cause of nutritional changes to foods. This occurs when food is exposed to air. At the time of harvest or slaughter, most foods are likely to contain contaminants, to have components which are inedible or to have variable physical characteristics (for example shape, size or colour). It is therefore necessary to perform one or more of the unit operations of cleaning, sorting, grading or peeling to ensure that foods with a uniformly high quality are prepared for subsequent processing. Thermal processing leads to reduction of nutritional quality and generation of off flavour, off colour and other sensory properties of food products. Therefore, in order to improve food quality and sensory properties, novel non-thermal food processing technologies are needed. The various non-thermal food technologies used now a day in food industries are discussed below.

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• \r\n High Hydrostatic Pressure (HPP)
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• \r\n Pulsed Electric Field (PEF)
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• \r\n Irradiation
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• \r\n Pulsed light technology (PLT)
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\r\n Food quality is an important concept because the food people choose depends largely on quality. Food quality must be monitored on a regular day-to-day basis to ensure that a uniform product is produced and that it meets the required quality control standards. Food quality has both subjective and non subjective aspects. Appearance, texture, and flavor are largely subjective attributes, whereas nutritional and bacterial quality are not. The last two qualities can be measured objectively by chemical analysis, by measuring bacterial counts, or using other specific tests. Currently, most of the traditional measuring techniques used to determine food quality are destructive (eg, texture, firmness, total soluble solids, acidity, color score, juice content) and involve random sampling, which increases the likelihood of an incorrect evaluation. Thus, nondestructive techniques, based on aroma characteristics, can offer the possibility to optimize food quality assessments.

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\r\n E-nose technology

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\r\n PTR–MS

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\r\n Ultrasound Technology

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\r\n Hyperspectral imaging

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\r\n Fluorescence excitation spectroscopy

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\r\n Nanotechnology

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\r\n Food Safety refers to handling, preparing and storing food in a way to best reduce the risk individuals becoming sick from foodborne illnesses. Antibiotic resistance in foodborne bacteria is a growing food safety challenge that is made worse by overuse of antibiotics in people and food animals. Cooked foods should not be left to sit in room temperature for longer than two hours. These foods should be cooled rapidly and kept refrigerated, preferably at a temperature under 5°C. Microorganisms can reproduce very rapidly at room temperature. Food can become contaminated at any point of production and distribution, and the primary responsibility lies with food producers. The basis of the food-safety system to be adopted in the food industry consists of a combination of good manufacturing practices (GMP), sanitation standard operating procedures (SSOP), and a hazard analysis and critical control point (HACCP) system.

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\r\n Food engineering includes the study of engineering properties, for example, compositional properties like boiling or freezing point; physical characteristics such as size, shape, volume, surface area, density, and porosity; mechanical properties such as compressive strength, impact, and shear; sensory properties such as texture and color; and thermophysical properties such as specific volume, specific heat, thermal conductivity, and viscosity. Today’s food engineering research leaders tend to be experts in materials science (e.g., rheology, mass transfer properties, and thermal and electrical food properties), applied mathematics and modeling, and biochemical engineering applied to foods. Food engineers of the future will advance the development of computational techniques as tools for process automation, control, design, and improvement. Novel technologies like the application of high hydrostatic pressure, pulsed electric fields, light pulses, oscillating magnetic fields, and ultrasound have the potential to impact nonthermal processing preservation.

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\r\n Food Adulteration refers to the process by which the quality or the nature of a given food is reduced through addition of adulterants or removal of vital substance. Food adulterants are the chemical substances present in food that cause harm or is unwanted in the food. Basically, during food adulteration, small quantity of non-nutritious substances are added intentionally to improve the appearance, texture or storage properties of the food. Food adulteration is quite common in the developing countries.

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\r\n Shelf life is “the period of time during which the food product will remain safe; be certain to retain its desired sensory, chemical, physical, microbiological, and functional characteristics; where appropriate, comply with any label declaration of nutrition data, when stored under the recommended conditions.” The shelf life of food products is an important feature for both manufacturers and consumers. The most important factor for shelf life evaluation of food is safety, followed by quality including physical, chemical, and sensorial properties. To prolong the shelf life of foods, it is crucial to minimize the rates of biochemical, enzymatic, and microbial degradation reactions. Commonly, this is achieved by ensuring proper sanitation conditions during slaughter or harvesting, processing foods to reduce water activity and damage enzyme functionality, and providing optimum temperature and relative humidity conditions during storage.

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\r\n Probiotics are healthful strains of live bacteria and yeast. Taking probiotics can provide a range of benefits, but it can also cause side effects. Some yogurts, supplements, and fermented foods, including kefir, sauerkraut, and tempeh, contain probiotics. The most common probiotics that manufacturers add to commercial products are species of Bifidobacterium and Lactobacillus bacteria. The body does not need the addition of food and supplements that contain probiotics to be healthy. However, food and supplements that contain probiotics assist the job of the "good" bacteria that are already present in your gut. Probiotics may help keep you healthy by: a)Decreasing the number of "bad" bacteria in your gut that can cause infections or inflammation (swelling) b) Stabilizing the digestive tract’s barriers against “bad” bacteria, or producing substances that hinder their growth. C) Replacing the body's "good" bacteria that have been lost, for example, when you take antibiotics.

\r\n Probiotics that are naturally found in your intestines include: Saccharomyces boulardii (a yeast) and bacteria in the Lactobacillus and Bifobacterium families of microorganisms. Probiotic supplements may be useful in treating and preventing inflammatory digestive tract conditions such as pouchitis (which affects people who have had their colons removed), inflammatory bowel diseases (such as ulcerative colitis and Crohn's disease), and chronic (long-term) stomach inflammation and ulcers caused by the Helicobacter pylori bacterium. Probiotics may also be helpful in treating constipation, irritable bowel syndrome, acid reflux, and spastic colon; shortening the duration of infectious diarrhea; and reducing the recurrence (return) of bladder and colorectal cancer. Probiotics are also being studied as a method of boosting the immune system. People who have weakened immune systems (on chemotherapy, for example), the critically ill, those who have had surgery, and very sick infants should use probiotics with caution, because infection has been occasionally reported.

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\r\n Spoilage microorganisms grow and produce different molecules that are involved in off-odor and off-flavor of foods. The spoilage depends on the microorganisms’ ability to adapt to the food ecosystem conditions and to metabolize the matrix. In particular they produce different compounds such as esters, ketones, aldehydes, hydrocarbons, alcohols, benzenoids, terpenoids, nitrogen, and sulfur compounds, amines, and volatile fatty acids (Dainty et al., 1985). All these compounds can characterize either the aroma or the spoilage. “Volatile fatty acids and ketones contribute with fatty/gamy/cheesy/dairy notes; aldehydes with their fatty/grassy odor considered fresh and agreeable at low levels, but unpleasant and rancid when concentrations rise; alcohols and esters with their ethereal/fruity/sweet nuances; benzene, sulfur, and terpene compounds with reminiscent plastic, cabbage, and floral/citrus odor, respectively.” The equilibrium among these compounds generates pleasant and typical meat and meat product aromas; on the other hand a disequilibrium creates off-odor and off-flavor. In particular in these activities either SSO or other microorganisms are involved

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\r\n Food spoilage results when microbiological, chemical, or physical changes occur, rendering the food product unacceptable to the consumer. Microbiological food spoilage is caused by the growth of microorganisms which produce enzymes that lead to objectionable by-products in the food. A significant proportion of the loss is due to spoilage by microorganisms, resulting in final products with an inadequate shape or appearance. It has been estimated that about 25% of all foods produced globally are lost due to microbial spoilage. Spoilage microbes are often common inhabitants of soil, water, or the intestinal tracts of animals and may be dispersed through the air and water and by the activities of small animals, particularly insects. Troublesome spoilage microorganisms include aerobic psychrotrophic Gram-negative bacteria, yeasts, molds, heterofermentative lactobacilli, and spore-forming bacteria. Psychrotrophic bacteria can produce large amounts of extracellular hydrolytic enzymes, and the extent of recontamination of pasteurized fluid milk products with these bacteria is a major determinant of their shelf life. Fungal spoilage of dairy foods is manifested by the presence of a wide variety of metabolic by-products, causing off-odors and flavors, in addition to visible changes in color or texture. Therefore, it is important not only to grow more, but also to save what is grown at high cost.

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\r\n Foodborne illnesses may lead to dehydration, hemolytic uremic syndrome (HUS), and other complications. Acute foodborne illnesses may also lead to chronic—or long lasting—health problems. Some foodborne illnesses lead to other serious complications. For example, C. botulinum and certain chemicals in fish and seafood can paralyze the muscles that control breathing. L. monocytogenes can cause spontaneous abortion or stillbirth in pregnant women. Acute foodborne illnesses may lead to chronic disorders, including reactive arthritis, irritable bowel syndrome and Guillain-Barre syndrome.  The only treatment needed for most foodborne illnesses is replacing lost fluids and electrolytes to prevent dehydration. If diarrhea is caused by bacteria or parasites, over-the-counter medications may prolong the problem. Medications to treat diarrhea in adults can be dangerous for infants and children and should only be given with a health care provider’s guidance. Hospitalization may be required to treat life threatening symptoms and complications, such as paralysis, severe dehydration, and HUS. Foodborne illnesses can be prevented by properly storing, cooking, cleaning, and handling foods.

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\r\n Microorganisms are key factors both in food processing and spoilage. Either added purposely or acquired from contact with the environment, all must deal with conditions imposed to eliminate or control the growth of pathogens and compete with each other for the nutrients that are abundantly available. Quantitative modelling of food microbial ecosystems must thus take into account the metabolic adaptations of each type of microorganism to temperature, pH, water activity, oxygen and the physical structure of the food environment. The next step is measuring the impact of interactions, both positive and negative, between microbial species.

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\r\n Almost all groups of microorganisms harbour members that under some conditions can contribute to spoilage of foods. Theoretically, one can assume that all microorganisms are initially present on a food pro-duct where after a selection occurs based primarily on nutrient composition and on the chemical and physical parameters. The interactions between microorganisms may be classified on the basis of their effects as being detrimental or beneficial. Several types of interactions have been studied in food eco-systems including both antagonistic and coordinated behaviour and interactions where growth or a particular metabolism of one organism is favoured by the growth of another organism. Below are three examples of such behaviour:

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1. \r\n Antagonism: is caused by the competition for iron as mediated by bacterial siderophore production and subsequent suppression of maximum cell density of less competitive bacteria
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2. \r\n Metabiosis: Change in spoilage profile of an organism by the supply of nutrients from another microorganism
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3. \r\n The ability of Gram-negative bacteria to coordinate the expression of certain phenotypic traits (e.g.hydrolytic enzymes) through bacterial communication via N -acyl homoserine lactones (AHLs).
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\r\n Food poisoning also called foodborne illness is infection or irritation of the gastrointestinal (GI) tract caused by food or beverages that contain harmful bacteria, parasites, viruses, or chemicals. The symptoms and severity of food poisoning vary, depending on which bacteria or virus has contaminated the food. Most foodborne illnesses are acute. Rarely, foodborne illnesses may lead to more serious complications. While the very young, the elderly, and persons with weakened immune systems are at greatest risk of serious consequences from most foodborne illnesses. The majority of foodborne illnesses are caused by harmful bacteria and viruses. Some parasites and chemicals also cause foodborne illnesses. Following four simple steps at home — Clean, Separate, Cook, and Chill — can help protect you and your loved ones from food poisoning.

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\r\n Spoilage molds can be categorized into four main groups: Zygomycetes, Penicillium, Aspergillus and other molds. Yeasts and molds are responsible for dairy product spoilage, resulting in significant food waste and economic losses. In addition, some species belonging to the genera Aspergillus, Fusarium and Penicillium are mycotoxigenic. Mycotoxins are a class of highly toxic chemical compounds produced under specific environmental conditions by several molds. The presence of this diverse group of fungal secondary metabolites on feed or food presents wide fluctuation from year to year mainly because of the large number of factors affecting fungal invasion and growth. Some of these critical factors include fungal strain and inoculum concentration, climate and geographical conditions, cultivation techniques and postharvest handling. Consumption of food contaminated with mycotoxins has been linked with carcinogenic, nephrotoxic and teratogenic potency and, generally, suppressive actions on the immune system.

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\r\n Spore-forming bacteria are usually associated with spoilage of heat-treated foods because their spores can survive high processing temperatures. These Gram-positive bacteria may be strict anaerobes or facultative (capable of growth with or without oxygen). Some spore-formers are thermophilic, preferring growth at high temperatures (as high as 55ºC). Some anaerobic thermophiles produce hydrogen sulphide (Desulfotomaculum) and others produce hydrogen and carbon dioxide (Thermoanaerobacterium) during growth on canned/ hermetically sealed foods kept at high temperatures, for example, soups sold in vending machines.

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\r\n Other thermophiles (Bacillus and Geobacillus spp.) cause a flat sour spoilage of high or low pH canned foods with little or no gas production, and one species causes ropiness in bread held at high ambient temperatures. Mesophilic anaerobes, growing at ambient temperatures, cause several types of spoilage of vegetables (Bacillus spp.); putrefaction of canned products, early blowing of cheeses, and butyric acid production in canned vegetables and fruits (Clostridium spp.); and "medicinal" flavors in canned low-acid foods (Alicyclobacillus). Psychrotolerant sporeformers produce gas and sickly odors in chilled meats and brine-cured hams (Clostridium spp.) while others produce off-odors and gas in vacuum-packed, chilled foods and milk (Bacillus spp.).

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\r\n Lactic acid bacteria (LAB) are a group of Gram-positive bacteria, including species of Lactobacillus, Pediococcus, Leuconostoc and Oenococcus, some of which are useful in producing fermented foods such as yogurt and pickles. However, under low oxygen, low temperature, and acidic conditions, these bacteria become the predominant spoilage organisms on a variety of foods. Erwinia carotovora is one of the most important bacteria causing soft rot of vegetables in the field or stored at ambient temperatures.

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\r\n Foodborne pathogens are mainly bacteria, viruses, or even parasites that are present in the food and are the cause of major diseases such as food poisoning. According to the U.S. Food and Drug Administration (FDA), foodborne pathogens are categorized according to the specific foods that are consumed. Campylobacter sp. (mostly associated with raw or undercooked poultry) is the major foodborne pathogen in the U.S. food supply, causing more than two million infections per year, while Salmonella, mostly found in meat, poultry, and eggs, is responsible for more than one million cases of food poisoning. Shigella, Escherichia coli, Clostridium botulinum, Clostridium perfringens, Yersinia, Vibrio cholerae, V. vulnificus, V. parahaemolyticus, Staphylococcus aureus, Bacillus spp., and Listeria also cause foodborne disease. Several types of viruses cause significant damage to the human body such as rotaviruses, noroviruses, adenoviruses, hepatitis A viruses, and astroviruses. Parasites are another category of foodborne pathogens, the main ones being Cryptosporidium parvum, Cyclospora cayetanensis, Giardia lamblia, and Toxoplasma gondii, and of these, 71% of waterborne diseases are caused by G. lamblia and Cryptosporidium.

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\r\n Canning is a method of preserving food in which the food contents are processed and sealed in an airtight container.  Canning provides shelf life typically ranging from one to five years, although under specific circumstances it can be much longer A freeze-dried canned product, such as canned dried lentils, , could last as long as 30 years in an edible state. Leakage is the most common cause of microbiological spoilage in canned foods.  Spoilage in canned foods by leakage can be caused by a variety of microorganisms that do not normally survive the heat treatment.  These microorganisms usually enter at the start of cooling through a faulty seam and produce a swelled can. Thermoanaerobacterium with the production of large quantities of H2 and CO2 gases, and causing sour fermentation at high temperatures in medium‐acid canned foods. Some species of spore‐forming psychrophilic bacteria have the ability to spoil refrigerated canned foods with production of gas, off‐flavors, and odors. The most important chemical spoilage of canned foods is the hydrogen swelling. Spoilage in these products does occur as a result of:

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\r\n 1.   Preprocess spoilage

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\r\n 2.   Inadequate processing

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\r\n 3.   Post-processing contamination

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\r\n Food waste and loss is a large and increasingly urgent problem and is particularly acute in developing countries where food loss reduces income by at least 15% for 470 million smallholder farmers and downstream value chain actors. Food loss (spoilage) receives less media visibility than food waste. Food loss is associated with developing world issues within the food supply chain (such as storage, refrigeration and transportation), while food waste is discussed in terms of developed countries that throw out already‐processed foods. The wastage of food becoming such a serious issue that it could as well be made a crime, it's high time we adopt measures to curb the problem. Cross-contamination can make food can become unusable. To avoid that Separating the food storage areas and food preparation areas is a necessity that needs to be adopted. Ecosystem impacts of food wastage are greater in areas where production is more resource intensive, and over half of these impacts are addressable across the developed world. In the United States alone, the 34 million metric tons of food waste is one seventh of landfill mass and emits methane as damaging as adding 4 million cars to the road. Waste prevention includes activities that avoid waste generation, for instance, reduction of food surplus, whereas waste management includes the options available to deal with food waste once it has been generated, such as composting and anaerobic digestion. We can reduce the food waste by following the food waste hierarchy: Prevention, re-use, recycle, recovery and disposal.

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