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Applied food microbiology - Coggle Diagram
Applied food microbiology
Food safety → Sicurezza igienica sanitaria Food security
Functional properties fermented foods → Technological and health promoting In the
production of foods is important the preventing approach
The GHP (Good Hygiene Practices) and the GMP are important in the contest of the food safety because are system and practices that define and determine guidelines to obtain a safe food-product.
quality is divided in negative and positive attributes. A food safety management system (FSMS) is a controlled process for managing food safety to ensure that all
food that is produced is up to quality standards and safe to consume.
The risk analysis is performed by scientist (science based)
risk assesment is divided in: hazard identification, we know that all the members of a specific specie have the same negative impact
hazard characterisation--> define the consumers that are more vulnerable, the dose-response relationship,
and the trait that leading the illness so the symptoms
risk characterization--> an estimation of occurence and severity of known or potential adverse health effects in a population based on the preceding steps
This Regulation 178/2002 provides the basis for the assurance of a high level of protection of human health and
consumers' interest in relation to food
common principles and responsibilities, the means to provide a strong science base
protection of human life and
health and the protection of consumers' interests, the protection of animal health and welfare, plant health and the environment.
Food law shall aim to achieve the free movement in the Community of food and feed. Risk assessment shall be based on the available scientific evidence and undertaken in an independent, objective and transparent manner. Risk management shall take into account the results of risk
assessment.
responsibilities--> food and feed business operators--> their control shall ensure that foods or feeds satisfy the requirements of food law
Member States shall
enforce food law and monitor and verify that the relevant requirements of food law are fulfilled by food
it is important the traceability system and Food business operators shall collaborate
rapid alert system for the notification of a direct or indirect risk to human health deriving from food or feed
is hereby established as a network.
Regulation 852/2004--> Primary responsibility for food safety rests with the food business operator.
It is necessary to ensure food safety throughout the food chain, starting with primary production.
It is important, for food that cannot be stored safely at ambient temperatures, particularly frozen
food, to maintain the cold chain.
General implementation of procedures based on the HACCP principles, together with the application of good hygiene practice, should reinforce food business operators' responsibility.
this regulation shall not apply to--> primary production for domestic use, domestic preparation, handling or storage of food for private domestic consumption, the direct supply, by the producer, of small quantities of primary products to the final consumer
or to local retail establishments directly supplying the final consumer; collection centres and tanneries which fall within the definition of food business only because they handle raw material for the production of gelatine or collagen
Regulation 882/2004--> controls to preventing, eliminating or reducing risks for guman and animals, Guaranteeing fair practices in feed and food trade and protecting consumer interests
regulation 2073/2005--> micro organism--> parasitic. Microbiological criterion--> acceptability of a product, a batch of
foodstuffs or a process, based on the absence, presence or number of micro-organisms, and/or on the quantity of their toxins/ metabolites. Food safety criterion---> actions to maintain the hygiene of the process. ‘Batch’ means a group or set of identifiable products obtained from a given process under practically identical circumstances and produced. Shelf-life’ means either the period corresponding to the period preceding the ‘use by’ or the minimum durability date. Ready to eat food
food business is based on HACCP rules, that the supply, handling and processing of raw materials and foodstuffs under their control are
carried out in such a way that the process hygiene criteria are me. The food safety criteria applicable throughout the shelf-life of the products can be met under
reasonably fore seeable conditions of distribution, storage and use.
Food safety criteria → Are defined the food category, the limits, sampling plans, analytical method, microorganisms, stage where the criterion applies.
For the hygiene criteria, we talk about not pathogens bacteria, but bacteria that can determine an alteration--> we perform several dilutions because the number of microorganisms is high
We talk about a complex microbial community, his situation
is a dynamic environment, because with time and different condition can change
growth the number of cells increase, and
the environment are non hostile. survival period the
number of new cells is equal to the number of dead cells and there is a non-lethal environment, death period we have a negative environment with the application of lethal factor such as high temperature
microrganism--> the pathogen that should be
eliminate in order to reduce infection and intoxication, spoilage microorganisms in which we should limit their
growth and then the technological microorganisms
Temperature--> Minimun growth T, optimum growth (max growth), maximum growth T.
PSYCHROPHILES grow best between -5-20°C, PSYCHROTROPHS (0°C-30°C) difficult to control at low T°C. MESOPHILES grow best between 10°C and 40°C → most common in food. THERMOPHILES grow best at temperatures above 40-70°C. HYPERTHERMOPHILES organisms that can survive to high temperatures but don't grow well at such temperatures.
for this reason we have to design a food to reduce bacteria proliferation like ph or water.
increase T= denaturation of protein--> heat stock proteins--> inactivation microrganism. With low T we have the production of cold shock proteins.
In these years there was a change for biostatic tretments
PH--> important value for the conservation, Lactic acid bacteria can be considered acid tolerance, while the acetic acid bacteria are acidophiles. Inorganic acids don't pass the membrane
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Water activity aw: it is the water available to an organism. It is defined as the ratio between the pression of food to the pression of water
While, the bacteria, in particular gram negative, has a very short range
(0.85-1.0). Halophilic bacteria. Reduction of water activity decreases, growth but promotes survival
Microaerophiles microorganisms require a low amount of oxygen. In the vacuum packages we remove the air--> substitution the oxygen with nitrogen--> reduction presence of spoilage
microbial interactions--> competition, inhibitory substances, quorum sensing, organization in biofilms. Cell to cell physical interactions and contact: if the food is liquid the probability of contact is major than in
solid food.
microbial metabolism--> energy produce. adenosine triphosphate (ATP is a molecule
with high phosphate group donor potential). Reducing power
The nicotinamide ring is able to accept two electrons together
with a proton (hydride ion, H-), forming NADH (reduced form). Catabolic pathways are sequences of chemical reactions in which carbon compounds are degraded
Fermentation (rigorous, chemical definition): it is a process in which no net oxidation-reduction occurs;
the electrons of the substrate are distributed among the products
the process used to
generate ATP is called substrate-level phosphorylation
Respiration: it is a catabolic pathway by which organic compounds (such as C6H12O6) can be completely
oxidized to carbon dioxide. electron transport chain are contained. ATP is generated at the expense of the
proton gradient upon return of the protons through a transmembrane enzyme complex (ATPase)
In fermentation there is a lower production of 2
molecules of ATP. Lattobacilli omofermentanti. Le specie del gruppo fermentano gli esosi e producono quasi esclusivamente acido lattico, Lattobacilli eterofermentanti obbligati: fermentano gli esosi a lattato
DAIRY PRODUCTS: we should use the correct starter culture for a specific fermented food product.
Starter cultures are an essential component of nearly all commercially produced
Fermented dairy products → Starter cultures
Homofermentative lactic acid bacteria.
BACTERIA → Influence on flavour and texture of final food product: lactic--> strains that metabolize citrate, aroma and CO2. Propionibacteria--> Propionibacterium freudenreichii subsp. shermanii metabolizes L-lactic acid to propionic
acid, acetic acid, and CO2 – eyes in swiss type cheeses.
YEASTS and MOULDS → Influence on flavour formation. The acidification process is the most important process
performed by LAB thanks the production of lactic acid --> need to be consistent and predictable
There are several effects of pH: technological effects consequences for the development of flavor and physical
properties (body and texture). Safety effect (control of foodborne pathogens). Quality
sources of bacteriophages--> raw materials, air of surfaces. Control measures like sanitation, raw materials--> bacteriophages recognition of potential hosts occurs through a bond that is established between the proteins of the capsid and specific receptors located on the wall of the host bacterium
lytic cycle--> virus kills the host. After a virulent virus has linked to a bacterium and injected its own nucleic acid
The virus completes a lysogenic cycle, that is, it postpones reproduction by inserting its own nucleic acid into the genome of the host cell. In lysogenic bacteria, phage DNA integrates into the bacterial chromosome. The virus thus integrated is a non-infectious entity and is called a prophage.
lactic bacterias are probiotics useful for the acidity into the stomach
Fermentation: for set yogurt, incubation is directly made in the package pallets are placed in an incubation chamber, 42°C for 4 hours. For stirred and drinking yogurts
pH decrease (3.5-4.5 for milks, 4-4.6 for yoghurt) that cause coagulation. Citrate metabolism, Chromosome (thermophilic cultures) or plasmid (mesophilic cultures) encoded. They confer protection, but at the same time they are also involved in aggregation, virulence, perhaps carbohydrate storage