Food Science Exam 2

Types of microorganisms

- Bacteria

- Fungi (molds, yeasts)

- Viruses

- Parasites

Factors that affect bacterial and fungi growth

- Temperature

- Nutrients

- Oxygen

- pH

Infections

- Salmonella spp.

- Campylobacter jejuni

- E. coli

- Yersinia enterocolitica

- Listeria monocytogenes

Intoxication

- Staphylococcus spp.

- Costridium botulinum

- Clostridium perfringens

- Mycotoxins

Most risky foods

anything that is raw, unpasteurized, or has been contaminated by a person

Protecting home prepared foods

Clean, separate, cook, chill

Danger zone

keep hot foods above 135 degrees and below 41 degrees

Antibiotics

effective for fighting bacteria, but will not kill a virus

Salmonella enterica

sources: eggs and poultry

Campylobacter jejuni

- sources: poultry

- problem for fetuses and neonates with mortality rate up to 70%

Vibrio parahaemolyticus and vulnificus

sources: raw oysters, raw seafood

EHEC (enterohemorrhagic E. coli)

- sources: ground meats, raw milk, unpasteurized fruit juice, lettuce, bagged spinach, sprouts, frozen cookie dough

- Jack in the Box: 1993 outbreak in which 475 people were affected and 3 children died

Staphylococcus aureus

Food handler are a major cause

Streptococcus spp.

Food handlers are a major cause

Listeria monocytogenes

- Symptoms: brain inflammation, spontaneous abortion, blood infection, meningitis in newborns

- organism can grow at refrigerator temperatures

Clostridium botulinum

Spores are difficult to kill. The toxin is thermally labile (destroyed by boiling for 10 mins) however, spores are heat tolerant and can germinate at pH>4.6 in an anaerobic environment to produce toxin

Infantile Botulism

About 20% of cases are linked to raw honey consumption

Toxoplasma gondii

Domestic cats are definitive hosts. Wash hands after changing cat litter or handling soil

Norovirus

often reported on cruise ships

Mycotoxins

Corn, peanuts, and cotton are the primary crops affected by mycotoxin contamination in the U.S.

Classes of mycotoxins

- Aflatoxins

- Trichothecenes

- Fumonisms

- Zearalenone

- Ochratoxin A

- Ergot alkaloids

Water activity (aw)

the ratio of the vapor pressure of water in a food to the vapor pressure of pure water at the same temperature

Aw

- most molds 0.7-0.8

- most yeasts ~0.8

- gram positives 0.8-0.9

- gram negatives ~0.9

Microwave oven

Can cook unevenly and leave "cold spots" where harmful bacteria can survive

Milk pasteurization

- a heating process designed to kill harmful bacteria

- high temperature, short time (HTST): 160 degrees F for 15s

- ultra high temperature (UHT): 270 degrees F for 1s

AMS - USDA

Agricultural Marketing Service

Standard of Identity Rules

describe in detail what a food must contain and what is optional and sometimes describe the amount or proportion of ingredients or components

HACCP plan

- hazard analysis critical control point plan

- Required for meat, seafood, and juice processors

- requires development of a HACCP Plan which includes (7 steps):

1. Identify potential hazards

2. Identify critical control points (CCPs) where risks are elevated

3. Establish acceptable limits for each CCP i.e., temperature, pH, etc.

4. Monitor CCPs

5. Define corrective actions if CCP deviates from critical limits

6. Regularly evaluate HACCP Plan

7. Record keeping

cGMP

- current good manufacturing practice

- standards for operation

Thermal death curves

- z value: number of degrees requires to reduce the D value by a factors of 10

- z value is 15 degrees in canning

pH

Food can be cooked on open kettle if pH is less than 4.6, but must be cooked in a pressure canner if pH is greater than 4.6

FDA food plant inspections

Investigators identify themselves, show credentials, and issue a Notice of Inspection. They are allowed into the facility by law

Types of food recalls: USDA-FSIS

- Class I - Most serious. Reasonable probability of serious adverse health consequences or death

- Class II - Remote possibility of adverse health consequences

- Class III - Will not cause adverse health consequences

Food irradiation

The treatment of food with ionizing radiation which chops the pathogen's DNA and makes them incapable of replicating

1958 Food Additives Amendment - FFDCA

required labeling of irradiation as a food additive

FSMA

- Food Safety Modernization Act

- focused on prevention, increased surveillance, and better response and recovery from raw materials, production through supply and delivery

1906 Pure Food and Drug Act

Not very good because it didn't define what unadulterated food is

7 key elements of FSMA

1. Produce safety rule

2. Preventative control for human food

3. Preventative controls for animal food

4. Protection against intentional adulteration

5. Accredited third-party certification

6. Sanitary transportation for human and animal food

7. Foreign supplier verification program

Guidelines for GAPs

- Guide to Minimize Microbial Food Safety Hazards

for Fresh Fruits and Vegetables

- GAP compliance is used as a marketing tool

Acid foods

foods that have a natural pH of 4.6 or less

Commercial stability (shelf stability)

Means that products are free of viable microorganisms of public health significance as well as microorganisms that are capable of reproducing in food under normal, non-refrigerated conditions of storage and distribution

Processing authority

The processing authority is responsible for properly

establishing the scheduled process, which includes

parameters such as

- initial temperature of the product

- the process temperature and the process time

- any critical factors that may affect the attainment of

commercial sterility