FIE Lesson 1 Introduction to Food Microbiology 2024 PDF

LEGISLATION, HYGIENE AND APPLIED MICROBIOLOGY FOR FOOD SAFETY Introduction to Applied Food Microbiology Luca Fasolato Università degli Studi di Padova Dipartimento di Biomedicina C...

LEGISLATION, HYGIENE AND APPLIED MICROBIOLOGY FOR FOOD SAFETY Introduction to Applied Food Microbiology Luca Fasolato Università degli Studi di Padova Dipartimento di Biomedicina Comparata e Alimentazione This lesson is about fundamentals of food microbiology 1 Why Applied Food microbiology? 2  Why food microbiology? Mesure/estimate the shelf life Evaluate the risk associated to foodborne phatogen Evaluate and validate processes Assess real risk; design new food safety systems, ensure microbiological safety and hygiene criteria Through the study of food microbiology, we can determine the shelf life of food products, assess the actual risk of pathogenic growth, and validate processes and treatments. This helps us assess the real risk, design new food safety systems, and ensure microbiological safety and hygiene criteria. 3  The shelf life Gram-huss 1996 Understanding Shelf Life in Food Products Shelf life is a critical concept in food science, defined as the period during which a food product maintains its quality, safety, and desired characteristics under specified storage conditions. To accurately determine and predict shelf life, food scientists employ a variety of indicators and methods. In assessing shelf life, three main types of indicators are utilized: microbiological, chemical, and sensory evaluation. Among these, Specific Spoilage Organisms (SSOs) play a crucial role. SSOs are particularly important as they often can predict the number of days of shelf life more accurately than other measures. These organisms are responsible for spoilage and produce detectable metabolites that correlate closely with product deterioration. One of the advantages of focusing on SSOs is that measuring their presence and growth can precede the detection of chemical parameters typically used in legal standards. This allows for a more proactive approach to quality control and shelf life prediction. SSOs enable food scientists to correlate the commercial life of a product with its sensory life, providing a more comprehensive understanding of food quality over time. Chemical markers also play a significant role in shelf life determination. These are typically volatile substances produced by microorganisms during their metabolic 4 processes. Interestingly, these chemical indicators are often detectable in the later stages of a product's commercial life, serving as clear signs of advancing spoilage or loss of freshness. It's important to note that the microbial ecology of food products is complex. Within a single food item, there can be various microniches that influence microbial populations. Time is another crucial factor, especially in seafood or fresh meat products where the physical and chemical characteristics of aquatic organisms make them particularly susceptible to rapid changes. Not all microbial populations present during the spoilage process are relevant to determining food quality. Only certain populations with particularly active metabolisms in relation to alteration will produce compounds that are perceptible and indicative of spoilage. While general measures like total mesophilic count have their place in food microbiology, they are often insufficient for accurately predicting shelf life. SSOs, on the other hand, provide a more targeted and reliable approach to understanding how a food product will fare over time. Lastly, it's worth noting that chemical indicators, which represent the metabolites of microbial action, typically appear in the later stages of spoilage. While they may not provide early warnings, they are valuable in definitively determining the state of freshness and confirming whether a product has undergone significant alteration. In conclusion, understanding shelf life requires a multifaceted approach, considering microbiological, chemical, and sensory factors. By focusing on SSOs and their metabolites, along with other key indicators, food scientists (and food business operators) can more accurately predict and manage the shelf life of food products, ensuring quality and safety for consumers. 4  Food Hygiene and food-borne disease The supermarket Lidl in Austria and Germany has issued a product recall for all use by dates of two types of smoked trout fillets from the Danish manufacturer Agustson. Three European countries have recorded Listeria infections with fish being investigated as the source. Germany has reported 30 infections and, since November, two people in Austria and one person in Denmark has contracted the same strain of listeriosis. In Germany, patients were notified and transmitted to the Robert Koch Institute (RKI) from the end of September to mid-November. They are 38 to 93 years old and 26 people were hospitalized. One person died but a detailed cause of death was not reported. In Denmark, there is no exposure information available for the one patient. The Listeria monocytogenes isolate has the sequence type (ST) 394 and is very rare among Danish patients. Source under investigation In Austria, the foodborne disease outbreak investigation involves the Austrian Agency for Health and Food Safety (AGES), Federal Ministry for Social Affairs, Health, Care and Consumer Protection (BMSGPK) and relevant regional authorities. Officials said initial investigation findings point to chilled smoked trout fillet from Denmark as the source. Lidl issued a recall in Austria and GermanyHowever, a spokeswoman for RKI in Germany said investigations to confirm the source are ongoing. 5 “RKI currently conducts patient interviews and for us a slightly different picture might emerge. Not all patients recalled trout consumption and different retail chains were visited for food shopping,” she told Food Safety News. “The outbreak clone is a Listeria monocytogenes strain belonging to serogroup IIa, a Listeria monocytogenes serogroup that is commonly associated with listeriosis in humans. Whole genome sequencing classifies this strain as a new genetic subtype, not detected previously, but the strain does not represent a novel species or any other novel type of pathogen.” Lidl recall and manufacturer’s view German authorities have informed member states via the Rapid Alert System for Food and Feed (RASFF) that Listeria has been detected in chilled smoked trout fillets from Denmark. The supermarket Lidl in Austria and Germany has issued a product recall for all use by dates of two types of smoked trout fillets from the Danish manufacturer Agustson. Nautica Regenbogen Forellenfilets 125-gram in the varieties of natural and with pepper are affected and have DK 4566 EG on the package. Agustson CEO Esben Andersen said the company has not agreed to a product recall. “All sampling of our finished products including sampling of our retained samples show negative Listeria results. All laboratory results — including the lab reports sent to us by Lidl — certify that our products are suitable for human consumption.” Andersen added the recall was not done by German authorities but Lidl decided to take such action on its own initiative. 5  Design a product aw pH LAB 0.97 6 9 0.965 8 5.8 0.96 7 0.955 5.6 6 Log10UFC/g 0.95 5 aw pH 5.4 0.945 4 0.94 5.2 3 0.935 2 5 0.93 1 0.925 4.8 0 0 200 400 600 800 1000 1200 0 200 400 600 800 1000 1200 Hours Hours How to design a salami fermentation? Products with pH ≤ 4,4 or aw ≤ 0,92, products with pH ≤ 5,0 and aw≤ 0,94 foodstuffs that do not support the growth of Listeria!!!!! Designing a Safe and Quality Salami: Designing an effective salami fermentation process requires a delicate balance between ensuring food safety and maintaining product quality. Key to this process is understanding and controlling factors that inhibit the growth of pathogens, particularly Listeria monocytogenes. European regulations provide crucial guidelines for creating foodstuffs that do not support Listeria growth. These guidelines specify two important thresholds: Products with pH ≤ 5.0 and water activity (aw) ≤ 0.94 Products with pH ≤ 4.4 or aw ≤ 0.92 Water activity (aw) is a measure of the freely available water in a food product, which is essential for microbial growth. pH, on the other hand, indicates the acidity level of the product. (negative logarithm of H+) By carefully monitoring these physico-chemical parameters, manufacturers can make informed technological decisions. For salami production, this involves determining the optimal curing period that allows the product to reach safety thresholds - typically aiming for a pH around 5.0 and aw below 0.94. This approach ensures the production of high-quality salami that is not excessively acidic yet safe from the risk of Listeria contamination. Lactic Acid Bacteria (LAB) play a crucial role in this process. These beneficial bacteria, 6 naturally present or added as starter cultures, produce organic acids, primarily lactic acid. This not only helps in reaching the desired pH levels to inhibit pathogens but also contributes to the characteristic flavor profile of the salami. In conclusion, designing a safe and high-quality salami involves a careful consideration of fermentation parameters, particularly pH and water activity. By adhering to regulatory guidelines and understanding the role of LAB, manufacturers can produce salamis that are both safe and delicious, striking the perfect balance between food safety and sensory quality. 6  Summary Microorganisms in Food Biological Hazard (Hazards vs Risk) Classification of Food Borne Disease (active learning) Pathogens vs Spoilers vs Indicators vs starter Application: the root-cause analysis (Home work) 7 Quiz Time 8  Time for KAHOOT Join with the Kahoot! app or at kahoot.it with Game PIN: …….. https://create.kahoot.it/details/100fa5ca-a2cd-4a0d-b574-c59a0f15eab9 9 Microorganisms in food 10  MICROBIOLOGICAL QUALITY HEALTH Quality - assessing Safety Presence/Absence of foodborne HYGIENIC Quality - assessing GENUINENESS – conformity to requirements The definition of different microbial populations is instrumental in evaluating various aspects of a food product's microbiological quality. Specific microorganisms can provide valuable insights into the suitability, safety, hygiene, and conformity of a food product. Health Quality - Assessing Safety: The presence or absence of particular microorganisms, such as the absence of Salmonella in 25 grams, serves as an indicator of the product's safety and suitability for consumption. It reflects the health quality and safety standards of the product. Hygienic Quality - Assessing Hygiene Conditions: Certain microbial populations, like enterobacteria or E. coli, act as indicators of the hygiene conditions within the product or during the production process. Their presence can be indicative of fecal contamination, highlighting the importance of hygienic practices. Genuineness - Conformity to Requirements: In some cases, specific microorganisms are essential for determining whether a product aligns with particular guidelines or regulations. For example, in yogurt or salami, beneficial microorganisms like lactic acid bacteria (LAB) are essential. The quantity of these microorganisms can confirm if the product meets the required criteria to be considered genuine. For instance, in yogurt, live and active lactic acid bacteria are required, with counts typically in the range of 10^7-10^8 CFU/ml or g. These microorganisms must remain viable and active throughout the entire storage period. In summary, the analysis of microbial populations in food products helps assess their safety, hygiene, and conformity to specific quality standards, making it a critical aspect of food quality control. 11  Microbial contamination-> transmission Microorganisms that can cause human health problems can be transmitted by several routes: Indirect even at great distances through water, insects,food, animals, etc... Vehicles Direct human to human contamination transmission. The most dangerous part of our body to pass the harmful microbes to food consists of the hands One of the most significant vectors of pathogenic microorganisms for humans is humans themselves. In various occupational activities, if individuals do not adhere to proper hygiene standards, they can become carriers of disease. The most critical pathway for transmitting harmful microbes to food is through direct contact, primarily involving hands. Microorganisms that can potentially jeopardize human health can be transmitted through various means, including: Indirect Transmission: This can occur even over considerable distances and involve intermediaries like water, insects, food, animals, etc. Direct Transmission: The most perilous route involves the direct transfer of harmful microbes from an infected individual to a healthy one. Hands, in particular, are a key vehicle for this type of transmission. In essence, it underscores the crucial role of maintaining hygiene and proper food handling practices, as well as the significance of human behavior in preventing the spread of pathogenic microorganisms that can pose health risks. 12  Microbial contamination Humans……are the key of microbial contamination Humans: The Epicenter of Microbial Contamination Humans play a pivotal role in the complex web of microbial contamination, often serving as both the source and the endpoint in the transmission cycle of foodborne pathogens. This interconnected network of contamination highlights the critical importance of human behavior and hygiene in food safety. The contamination cycle typically begins with infected individuals. Through bodily excretions such as vomit and diarrhea, humans can introduce pathogens into various environmental reservoirs: Water sources become contaminated, potentially affecting irrigation systems and drinking water. The environment, including soil and surfaces, can harbor these microorganisms. Human hands, a primary vector, can transfer pathogens directly to food or other surfaces. Air can carry aerosolized particles containing microbes, especially in enclosed spaces. These contaminated elements - water, environment, hands, and air - then serve as vehicles for pathogen transfer to food products. Contaminated food, in turn, becomes the carrier that completes the cycle, potentially infecting consumers and perpetuating the contamination chain. This cyclical nature of contamination underscores the crucial need for stringent 13 personal hygiene practices, particularly in food handling environments. It also emphasizes the importance of environmental sanitation, water treatment, and air quality control in food production and preparation areas. Understanding this human-centric contamination cycle is essential for developing effective strategies to break the chain of transmission and ensure food safety throughout the production and consumption process. 13  Primary and secondary contamination Contamination at the origin (Primary) In each food the microbiota is strictly dependent on the nature of the raw materials and the environment in which the food are produced (cultivation, breeding) and the conditions in which they are processed, stored and consumed. Obviously there is a microbiota associated with raw materials, which represent the natural habitat; however, different circumstances may occur which may result in quantitative and/or qualitative changes in the contaminating micro-organisms Contamination due to processing practices (Secondary) The main source of secondary contamination of food is human and the equipment used for processing. It is therefore very important that hygiene rules are strictly followed during food processing and preparation. Understanding Food Contamination: From Origin to Processing Food contamination is a complex process that occurs at various stages of food production and handling. It can be broadly categorized into two main types: primary (at the origin) and secondary (during processing). 1.Primary Contamination (Contamination at the Origin): Primary contamination is intrinsically linked to the nature of the raw materials and the environment in which food is produced. The microbiota of each food item is uniquely dependent on: The inherent characteristics of the raw materials The environment of production (cultivation fields, animal breeding facilities) Conditions of initial processing and storage This initial microbiota represents the natural habitat of the food. However, various factors can lead to quantitative and/or qualitative changes in the contaminating microorganisms. For example: In crop cultivation: soil quality, irrigation water, and agricultural practices In animal husbandry: living conditions, feed quality, and health status of animals In seafood: water quality and environmental conditions of the catch area In meat processing, a critical point of primary contamination occurs at the slaughterhouse. When an animal is slaughtered and its hide is removed, the exposed 14 carcass becomes highly susceptible to microbial contamination from the animal's own microflora, environmental contaminants, and potential cross-contamination from equipment or workers. 2. Secondary Contamination (Contamination due to Processing Practices): Secondary contamination occurs during the subsequent handling and processing of food products. The main sources of secondary contamination are: Human handlers: Through direct contact, poor hygiene practices, or illness Equipment: Improperly cleaned or maintained processing machinery Environment: Contaminated air, water, or surfaces in processing facilities This type of contamination can occur during various stages: Collection and initial processing Storage and transportation Cutting and further processing Cooking (where applicable) Packaging Retail display and handling It is crucial to note that while primary contamination may be partially unavoidable, secondary contamination can be significantly reduced through strict adherence to hygiene rules and proper food safety practices. To minimize secondary contamination: Implement rigorous personal hygiene protocols for food handlers Maintain clean and sanitized equipment and processing environments Ensure proper temperature control during storage and transportation Follow HACCP (Hazard Analysis and Critical Control Points) principles Understanding both primary and secondary contamination is essential for developing comprehensive food safety strategies. By addressing potential contamination at every stage - from farm to fork - we can significantly reduce the risk of foodborne illnesses and ensure the production of safer, higher-quality food products. HACCP (Hazard Analysis and Critical Control Points) is a systematic preventive approach to food safety that identifies, evaluates, and controls biological, chemical, and physical hazards throughout the food production process. It is designed to prevent problems before they occur and ensure the safety of food products from primary production to final consumption. HACCP focuses on critical control points in food production where hazards can be prevented, eliminated, or reduced to acceptable levels. 14  Food contamination. Where, When, Whay? Primary production Raw materials Post-primary Air; surfaces; production ingredients Cross- contamination Operators Factors affecting Thermal abuse Poor Hygiene No GMP or GHP Primary and Post-Primary Contamination Along the Food Supply Chain: Along the food supply chain, we can identify primary and post-primary contamination. Primary contamination pertains to activities in the primary sector, including animal production, farming, and transportation to slaughterhouses. In the case of plant-based products, this encompasses field cultivation and the initial harvest without further handling. Primary contamination occurs through various pathways and sources, with water, air, and soil typically being the most significant. In post-primary contamination, during the processing and handling of products, the environment within food industries plays a critical role in contaminations. In these stages, the environment is controlled, and the air quality is monitored. However, factors such as surfaces and human manipulation (as humans can be a source of various issues like diseases transmitted by enteric viruses or fecal contamination due to poor hygiene, or staphylococci on skin surfaces) come into play. Cross- contamination is of great importance, involving the transfer from one surface to another, and it's also a concern for chemical risks like allergens. At this stage, the use of ingredients introduces additional potential hazards. Several factors can influence the situation: Thermal abuse; Poor hygiene; Lack of Good Manufacturing Practices (GMP) or Good Hygiene Practices (GHP) 15  Functional classification of Food Microorganisms Classification on way of actions Pathogens Alterants and Saprophytes (Unlikely Pathogens) Useful EURegulation defines Markers or Indicators Process hygiene Food safety Marker Organisms: Marker organisms indicate a potentially hazardous situation in a food product. For example, the presence of E. coli in bivalves, enterobacteriaceae in infant products (e.g., Cronobacter or Salmonella), or coagulase-positive Staphylococcus (S. aureus) in cheese can serve as markers for potential issues or dangers. Index Organisms: Index organisms are pathogens whose presence in food is hypothesized based on certain compositional, chemical, physical, or epidemiological conditions. They indicate the possible presence of specific pathogenic microorganisms. Indicator Organisms: These are organisms that are not harmful themselves but provide valuable information about the overall microbiological conditions of a product. They can be further categorized into two groups: Indicator Organisms for Microbiological Quality: These help evaluate the suitability of processing and storage conditions. Indicator Organisms for Microbiological Safety: These suggest the possibility of a microbiological hazard. Using indicator organisms allows for a faster assessment of the quality and safety of a product. They can help predict the product's shelf life. However, it's important to note that they do not replace specific microbiological criteria, and they are often groups of microorganisms rather than single entities. In summary, marker organisms alert to potential hazards, index organisms indicate possible pathogen presence, and indicator organisms provide insights into the microbiological condition and safety of a food product.  Food is unsafe if (reg. EU 178/2002)… unfit for human consumption: from a physiological point of view (depleted food, not regular in terms of quality, food must be excluded from the market but it is not dangerous for the consumer. (e.g. commercial fraud; putrefaction, deterioration or decay) injurious to health: when, under normal conditions of intake, the food is able to determine, and in fact determines, a damage to health: food borne pathogens (. See the definition on the Lectures of Prof. Novelli (Legislation) Spoilers vs foodborne disease Taking into consideration the definitions of food safety, we can include the presence of foodborne pathogens as injurious to health. It should be noted that pathogenic bacteria are not directly involved in the spoilage of food. If, for example, there is significant contamination of food with Salmonella, there won't be sensory changes that can help us recognize the presence of that hazard. In this context, "injurious to health" means harmful to human health. Foodborne pathogens like Salmonella can pose a health risk, even if they don't necessarily cause noticeable changes in the sensory attributes (taste, smell, appearance) of the food. This underscores the importance of food safety measures to prevent such pathogens from entering the food supply chain and reaching consumers. 17  Report some examples unfit for human consumption: injurious to health Discover in google or discuss with your colleagues in a little groups 18  Spoilers vs foodborne disease You must know your product! The jars can also swell after storage with a strong and nauseating smell, the dish is eaten outdoors. Ferment in barrels for one or two months and then canned in light brine During the production of surströmming, just enough salt is used to prevent the raw herring from rotting while allowing it to ferment. A fermentation process of at least six months gives the fish its characteristic strong smell and somewhat acidic taste Halanaerobium Take home message "First of all, you must know your consumer and the quality of your products: Quality perception varies significantly among countries, and the alterations differ based on the perceived quality. For example, fermented herring is a typical dish in Swedish cuisine. In this case, surströmming, a fermented fish, might seem disgusting to some, but it is enjoyed by the local consumer. First and foremost, remember that you need to understand your food products. Quality is a relative concept. The key takeaway here is to know your product to determine its quality and acceptability. 19 Beneficial, spoilage, and pathogenic microorganisms The good The Ugly The Bad 20 Biological Hazard Cross-interaction with the lecture of Prof. Balzan ( Food Hygiene) 21  Food Hazards Biological, chemical or physical agent contained in food or feed, capable of causing an adverse health effect, it can make the food inedible or cause medical damage Where? IT MAY ARISE AT ANY POINT OF THE PRODUCTION CHAIN Definition of Hazard: A hazard is a biological, chemical, or physical agent present in food or feed that has the potential to cause adverse health effects. It can render the food inedible or lead to medical harm. -Damage Induced by Different Hazards: Biological hazards (bacteria, parasites, viruses) can lead to foodborne illnesses and intoxication. Chemical hazards, on the other hand, can result in chronic issues due to the accumulation of substances in organs or acute illnesses from poisoning. Chemical hazards may also encompass foreign objects, causing injuries, choking, aversion, and physical harm. Sources of Origin: These hazards can originate from various sources and need to be studied based on the stage in the production chain. Their prevalence may increase or decrease along the supply chain. Many originate from raw materials, but they can also stem from other sources related to the production facilities. 22  Hazard and Risk European Food Information Council (EUFIC) https://twitter.com/EUFIC/status/1191272073425018880 ☢️A #hazard is something with the potential to cause harm ⚠️#Risk is the likelihood of a hazard causing harm 23  Definition of risk and hazard There are many definitions of RISK. According to the reg. 178/2002 ‘risk’ means a function of the probability of an adverse health effect and the severity of that effect, consequential to a hazard; ‘hazard’ means a biological, chemical or physical agent in, or condition of, food or feed with the potential to cause an adverse health effect; RISK = “probability of an adverse event, capable of causing damage, taking into account its potential impact at the time when it occurs.” 24  Food risk Risk "Function of the probability (frequency) and severity of an effect harmful to health derived from food", according to scientific research it results from the expression R = Severity X Occurence (frequency). This vision is accompanied by risk as the "probable magnitude of its consequences" which depends on subjective values and perception and responds to the expression R = Danger X Perception (Offense) Danger is what, in order to be part of the composition or to have put the food in a specific condition, makes it harmful to health. Not every hazard is related to a risk, but only when there is the likelihood of a serious adverse effect; The offense is based on the mental representation linked to the subjective value attributed. (Liuzzi, 2003). Reg. 2073/2005: Food products must not contain microorganisms, their toxins or metabolites, in quantities that represent an unacceptable risk to human health. The assessment of the probability (frequency) and severity of potential health hazards related to food is a fundamental aspect of food safety. This assessment is often expressed through a scientific perspective. Severity pertains to the magnitude of harm or damage that can occur, while occurrence refers to the frequency of such harm. In this context, risk is described as the "probable magnitude of its consequences," taking into account subjective values and perceptions. This relationship can be expressed as: R = Hazard X Perception (Offense) Here, "Danger" represents the elements or conditions in food that can render it harmful to health. It's important to note that not every hazard poses a risk; it only becomes a risk when there is a likelihood of causing a significant adverse effect. "Perception" is influenced by the subjective value attributed to the potential harm. Food products should not contain microorganisms, their toxins, or metabolites in quantities that pose an unacceptable risk to human health. However, the concept of risk also considers probability. For instance, the frequency of infections caused by Salmonella is relatively high (with a large number of cases each year) but typically results in minor harm, such as self-limiting gastroenteritis. Thus, the overall risk may be considered medium. Conversely, in the case of Listeria infections, although the frequency is lower, the 25 severity is significantly higher, especially among pregnant women, where it can lead to severe consequences like abortion. Therefore, the risk associated with Listeria can be considered medium to high. Evaluating risk in this manner allows for a more comprehensive understanding of potential health hazards related to food. 25  Determination of the Risk (in HACCP) Principle 1 determination of the Risk The table is a useful tool to determine the level of risk associated with specific food hazards. Indeed, the case of botulism in low-acid sterilized canned foods is a good example of how this assessment works. Despite the event being rare, with low frequency, the consequences of poisoning are severe or even lethal. Therefore, the risk associated with this hazard could be considered medium. Clostridium botulinum is a specific hazard associated with many sterilized products such as canned vegetables and homemade sterilized food. Its danger lies in its ability to produce a potent neurotoxin that can have severe health effects in humans. Even though incidents of botulism are rare, the risks associated with its consumption require strict prevention and control measures to ensure food safety. 26  Food risks relative priorities Risk Law Press FBO Environmentalist based on science Microbiological Nutritional Pollution Toxins Pesticides Additives Biotech FBO???????? The microbiological risks of food products Da Antoniazzi, 2003 Today are one of the main sources of human diseases caused by food Regulation 2073 MICRO Perception of food risks can vary significantly among different groups of people and organizations. Perceptions of risk vary depending on the specific audience and their interests. When it comes to law and legislation, the focus is often on chemical contamination and additives. In contrast, the mass media tends to emphasize biotechnology as a significant concern. However, for those involved in the food industry, microbiological hazards are of utmost importance. Environmentalists, on the other hand, are more concerned with issues related to biotechnology and additives. While these various perspectives exist, a risk assessment based on empirical analysis reveals that microbiological hazards, pollutants, and nutritional aspects are the primary concerns associated with food risks. These factors have a more substantial impact on public health and safety. 27