Lecture 2

Food spoilage is caused by the growth of microorganisms like bacteria, yeasts, and molds. Several factors influence microbial growth in food, including temperature, pH, moisture content, and nutrient levels. Food preservation techniques aim to inhibit microbial growth through methods like reducing water activity by drying and salting foods or lowering the pH. Proper control of factors like temperature, gases, and humidity during food storage is important for limiting spoilage.

The document discusses various topics related to food microbiology including the study of microorganisms in food, food preservation techniques, foodborne diseases, and food contamination. It provides details on industrial canning processes, irradiation, high pressure processing, and common foodborne pathogens and diseases. The goal of food preservation techniques is to prolong the shelf life of food by inhibiting spoilage microorganisms through methods like thermal sterilization, freezing, drying, fermentation and addition of preservatives.

This document discusses factors that influence the growth of microorganisms in food. It outlines the history of food microbiology and preservation methods. Intrinsic factors like pH, moisture content and nutrients and extrinsic factors like temperature, atmosphere and water activity determine which microbes can grow. Common preservation methods mentioned include canning, pasteurization, cooking, refrigeration, freezing and drying which make the environment unsuitable for microbial growth.

This document discusses the microbiology of various foods. It begins by introducing food microbiology and the importance of microorganisms in foods, both desirable and undesirable roles. It then discusses the microbiology of specific foods, including milk and milk products like cheese, butter, and ice cream. It describes the microorganisms commonly found in milk, how they grow, and their effects. It provides details on the microbiology of butter, sources of contamination, types of spoilage, and control methods. It also briefly mentions the microbiology of cheese and cottage cheese.

Microorganisms play important roles in food as pathogens that can cause disease, as spoilage organisms that degrade food quality, and as cultured microbes used in food processing. Fruits and vegetables naturally contain saprophytic bacteria and fungi that can lead to spoilage when the protective barriers are broken during harvesting or processing. The major factors affecting microbial growth in fruits and vegetables include physical damage, pH, moisture content, and temperature. Common preservation methods include drying, freezing, acidification, and use of preservatives.

The document discusses various methods of food preservation including: 1. Removing or killing microorganisms through methods like asepsis, filtration, washing, and heat treatment. 2. Maintaining conditions unsuitable for microbial growth using techniques such as low temperatures, drying, smoking, and chemical preservatives. 3. Combining preservation methods, for example pasteurizing then refrigerating foods, in order to lengthen the lag phase of microbial growth and prevent spoilage. Proper food preservation prevents foodborne illness and significantly extends the shelf life of foods.

This document discusses the principles of food preservation. It outlines four main approaches: 1) preventing or delaying microbial decomposition through asepsis, removal of microorganisms, or hindering their growth; 2) preventing self-decomposition of food by inactivating enzymes or chemical reactions; 3) preventing damage from insects, animals or mechanical causes; and 4) introducing few spoilage organisms, avoiding actively growing organisms, and using unfavorable conditions or actual damage to organisms to delay microbial growth. The key is lengthening the lag phase of microbial growth as much as possible to delay spoilage.

The document discusses factors that affect microbial growth in foods. It describes the microbial growth curve and identifies four main factors that influence growth: intrinsic properties of the food itself, extrinsic environmental conditions, implicit properties of microorganisms, and processing factors. Specific intrinsic factors discussed include nutrients, pH, water activity, and antimicrobial constituents. Extrinsic factors include temperature, relative humidity, and atmospheric gases. Implicit factors include microbial interactions like mutualism and antagonism.

-microorganisms are ubiquitous . They are harmful and also useful for the mankind . Different kind of foods can be prepared by microorganisms .

For food growth microbes play a very important role. there are two Factor which are required for microbial growth.

The document discusses food contamination and spoilage. There are three types of food contamination - chemical, physical, and biological. Biological contamination refers to substances from living organisms like microbes, bacteria, viruses or parasites that can cause foodborne illness. There are also four types of food spoilage - microbial, physical, chemical, and enzymic. Various methods can be used to prevent food contamination and spoilage, including proper hygiene, refrigeration, freezing, drying, smoking, and canning. Maintaining sanitation throughout processing and storage is important to prevent deterioration in food quality and safety.

This document defines key terms related to microbiology and food microbiology. It discusses how microorganisms can play two roles in relation to food - food spoilage or food production. Food spoilage occurs when microbes damage the original texture, flavor, and nutritional value of food, making it inedible. Factors like temperature, pH, and water activity determine if spoilage will occur. Food production uses microbes, through the process of fermentation, to generate preserved or new fermented food products like yogurt, cheese, and beer. Fermentation harnesses microbes to produce acids, alcohols and esters that preserve foods or create distinctive flavors.

The document discusses the various factors that can cause food spoilage. It identifies three main types of causes: biological, chemical, and physical. Biological causes include the growth and activity of microorganisms like bacteria, yeasts, and molds. Chemical causes involve reactions with oxygen and light as well as chemical reactions within food constituents. Physical causes consist of improper holding temperatures and physical abuse. Specific spoilage factors are then discussed in more detail, such as spoilage due to microorganisms, carbohydrates, proteins, lipids, rancidity, oxidative changes, and enzymes. Oxidation is highlighted as a major problem that can produce undesirable biochemical changes in foods.

This document discusses intrinsic and extrinsic factors that influence food spoilage. Intrinsic factors include moisture content, antimicrobial components, biological structures, pH, oxidation-reduction potential, and nutrient content. Extrinsic factors are environmental factors like storage temperature, relative humidity, and gases. Moisture content, pH, and nutrients influence which microbes can grow. Biological structures, antimicrobial components, and oxidation-reduction potential provide resistance. Storage temperature, relative humidity, and gases like carbon dioxide also impact microbial growth during processing and storage.

This document discusses food spoilage, foodborne diseases, and food quality and control. It defines food spoilage as when microorganisms, enzymes, insects, rodents, chemical reactions or environmental factors cause food to become unfit for consumption. Foodborne diseases can result from food infections, where food serves as a medium for pathogen growth, or food intoxications, where toxins in food cause illness. The document also discusses factors that influence food quality like appearance, texture and flavor, and the need for quality control to ensure consumer safety and satisfaction.

Food sanitation Food sanitation It included all practices involved in protecting food from risk of contamination, harmful bacteria, poisons and foreign bodies, preventing any bacteria from multiplying to an extent which would result in an illness of consumers; and destroying any harmful bacteria in the food by thorough cooking or processing. The primary tenet of food-service sanitation is absolute cleanliness It begins with personal hygiene, the safe handling of foods during preparation, and clean utensils, equipment, appliances, storage facilities, kitchen and dining room. Definition of terms  Food – Any substance whether simple, mixed or compounded that is used as food, drink, confectionery or condiments. Safety – is overall quality of food fit for consumption. Sanitation – is a health of being clean and conducive to health. Cleanliness – is the absence of visible soil or dirt and is not necessarily sanitized. Microbiology - the branch of biology that deals with microorganisms and their effect on other microorganisms. Microorganisms - organism of microscopic or submicroscopic Food Infection - microbial infection resulting from ingestion of contaminated foods. Food Intoxication - type of illness caused by toxins. Under favorable condition certain bacteria produce chemical compounds called toxins Food Spoilage - means the original nutritional value, texture, flavor of the food are damaged, the food become harmful to people and unsuitable to eat. Foodborne Illness – A disease carried or transmitted to people by food. Food Safety : A Top Priority Food safety is the responsibility in every person who is involve in food service. Serving safe food is the top priority for every food service employee. Dangers of food borne illness  Individual – Food borne illness are the greatest danger to food safety. It could result to illness or diseases to an individual that would affect their overall health, work and personal lives. Loss of family income  Increased insurance  Medical expenses  Cost of special dietary needs  Loss of productivity, leisure and travel opportunities  Death or funeral expense Establishment – Food borne illness outbreak can cost an establishment thousands of pesos, it can even be the reason an establishment is forced to closed.  Loss of customers and sales  Loss of prestige and reputation  Lawsuits  Increase insurance premiums  Lowered employee morale  Employee absenteeism  Increase employee turn over  Embarrassment Types of Food Contaminants  Biological Contaminants Physical Contaminants Chemical Contaminant Biological Contaminant – A microbial contaminant that may cause a food borne illness (bacteria, viruses, fungi, parasites, biological toxins) Examples: Sea food toxins Mushroom toxins Clostridium Botulinum Salmonella bacteria Preventing Bio

This document discusses various methods for controlling microorganisms in foods, including desirable and undesirable microbes. It outlines 11 main control or preservation methods: 1) controlling access through cleaning and sanitation, 2) physical removal techniques, 3) heat control through processes like pasteurization, 4) low-temperature control through refrigeration, 5) reduced water activity through drying or lowering moisture content, 6) pH and organic acid control, 7) modified atmosphere packaging to alter the oxygen level, 8) use of antimicrobial preservatives, 9) irradiation, 10) novel processing technologies, and 11) combination or "hurdle" approaches. Specific techniques are described for each category, along with their mechanisms of action against microbes.

SPSS Presentation. topics include general concepts of statistics, basic concepts of SPSS, Variables, types of variables, data and its types, sources of data,four windows of SPSS, viewer window, output viewer. results etc..............................

This document discusses how to use SPSS to transform and compute new variables from existing variables. It shows how to compute a new variable called "PARTICPN" by summing the values of variables p1, p2, p3, p4, and p5. It then demonstrates computing another new variable called "MEANPART" which calculates the mean of variables p1 through p5 by summing them and dividing by 5.

The document provides step-by-step instructions for defining variables and entering data in SPSS. It defines three variables - Gender, Age, and BRM1 (a questionnaire item) - including value labels. It then shows the responses for 10 respondents and instructs the user to enter the values in the Data View. Finally, it prompts the user to save the work.

The document provides instructions for obtaining Cronbach's alpha to measure the reliability of a scale in SPSS. It describes selecting "Reliability Analysis" from the "Analyze" menu, then dragging the scale items to the dialog box. It notes the output shows Cronbach's alpha of 0.915 based on 672 cases, indicating high internal consistency reliability of the scale, as removing any items would not increase the score.

This presentation includes the introduction of SPSS is basic features of Spss, how to input data manually, descriptive statistics and how to perform t-test, Anova and Chi-Square.

SPSS is a popular statistical software package that allows users to perform complex data analysis with simple instructions. It requires variables, data, measurement scales, and a code book to be defined. The document then describes different variable types (independent, dependent), measurement scales (nominal, ordinal, interval, ratio), how to start and use SPSS, and basic functions for data entry, analysis including frequencies, descriptives, correlation, and reliability which can be measured using Cronbach's alpha.

The document discusses temperature management and cooling techniques for horticultural produce after harvest. It states that temperature control is the most important factor for maintaining quality. There are two phases to temperature management - an initial cooling phase to remove field heat from the product, followed by a holding phase at the optimal temperature during distribution. The rate of cooling depends on the temperature difference between the product and coolant, contact between them, and their thermal properties. Different cooling techniques can be selected based on the perishability of the product, such as room cooling, forced-air cooling, hydro-cooling, vacuum cooling, or package icing.

Deterioration of fresh produce begins at harvest as the produce is removed from its source of water and photosynthetically active light. After harvest, produce relies on stored carbohydrates and continues to respire, using oxygen and releasing carbon dioxide and heat. The rate of respiration, and thus deterioration, increases with temperature and is higher for produce like broccoli and sweet corn. Proper postharvest techniques aim to slow respiration and deterioration by controlling factors like temperature, oxygen, and carbon dioxide levels.