Fertilizers, Pesticides, Preservatives, and Bacteria Food Safety Fertilizers, Pesticides, Preservatives, and Bacteria

Food Safety Explain the dynamics of integrated pest management practices and their relative effects upon society. Evaluate the nature of scientific and technological knowledge using case studies. Describe genetic engineering techniques, applications, and impacts. Evaluate the consequences and impacts of scientific and technological solutions. Apply the elements of scientific inquiry to solve multi-step problems. PA Standards 4.5.12.C: Integrated Pest Management 3.2.12.A: Inquiry and Design 3.3.12.C: Biological Sciences 3.8.12.C: Science, Technology, and Human Endeavors 3.2.12.C: Inquiry and Design “Since the mid-1940’s over 200 basic chemicals have been created for use in killing insects, weeds, rodents, and other organisms described in the modern vernacular as ‘pests.’” - Rachel Carson, Silent Spring, 1962

Key Questions How can we protect food resources from pests? What are the environmental effects of producing food? What laws govern the use of pesticides? What is Integrated Pest Management? How has the development of preservatives impacted food? What impact does foodborne illnesses have on the U.S.?

How can we protect food resources from pests?

PROTECTING FOOD RESOURCES: PEST MANAGEMENT Organisms found in nature (such as spiders) control populations of most pest species as part of the earth’s free ecological services.

PROTECTING FOOD RESOURCES: PEST MANAGEMENT We use chemicals to repel or kill pest organisms as plants have done for millions of years. Chemists have developed hundreds of chemicals (pesticides) that can kill or repel pests. Pesticides vary in their persistence. Each year > 250,000 people in the U.S. become ill from household pesticides.

What are the environmental effects of producing food?

Conventional Chemical Pesticides Figure 13.28 Trade-offs: advantages and disadvantages of conventional chemical pesticides. QUESTION: Which single advantage and which single disadvantage do you think are the most important? Which advantage/disadvantage do you feel is the most important?

Individuals Matter: Rachel Carson Wrote Silent Spring (1962) which introduced the U.S. to the dangers of the pesticide DDT and related compounds to the environment.

DDT DDT sprayed on Long Island beaches in 1945. It is also used in agriculture, sprayed on fields and sometimes from the air. It is far less poisonous than the pre-WWII arsenic compounds. Time magazine ad for DDT, we can look forward to a new era of prosperity and peace guided by science and technology.

Silent Spring Assignment Read the selection from Silent Spring by Rachel Carson. Answer the discussion points on the handout.

Pollution Each year pesticides: Kill about 1/5th of the U.S. honeybee colonies. 67 million birds. 6 -14 million fish. Threaten 1/5th of the U.S.’s endangered and threatened species. Figure 11.15 Natural capital degradation: bioaccumulation and biomagnification. DDT is a fat-soluble chemical that can accumulate in the fatty tissues of animals. In a food chain or web, the accumulated DDT can be biologically magnified in the bodies of animals at each higher trophic level. The concentration of DDT in the fatty tissues of organisms was biomagnified about 10 million times in this food chain in an estuary near Long Island Sound in New York. If each phytoplankton organism takes up from the water and retains one unit of DDT, a small fish eating thousands of zooplankton (which feed on the phytoplankton) will store thousands of units of DDT in its fatty tissue. Each large fish that eats 10 of the smaller fish will ingest and store tens of thousands of units, and each bird (or human) that eats several large fish will ingest hundreds of thousands of units. Dots represent DDT, and arrows show small losses of DDT through respiration and excretion. Example of biomagnification or bioaccumulation of DDT in an aquatic food chain.

The ideal Pesticide and the Nightmare Insect Pest The ideal pest-killing chemical has these qualities: Kill only target pest. Not cause genetic resistance in the target organism. Disappear or break down into harmless chemicals after doing its job. Be more cost-effective than doing nothing.

Superpests Superpests are resistant to pesticides. Superpests like the silver whitefly (left) challenge farmers as they cause > $200 million per year in U.S. crop losses. Silverleaf whitefly is a worldwide pest of numerous field and vegetable crops. It invaded southern California around 1990 and central California in 1992. Millions of dollars are spent each year in California alone to control the silverleaf whitefly. Several biotypes of this pest exist around the world and are known to rapidly gain resistance to insecticides. Program staff are working with scientists in the USDA, universities, and local county entomologists to reduce the impact of this pest. Several new, exotic parasites have been imported, evaluated and released into California. At least 3 new species have persisted and spread in Imperial Valley and the San Joaquin Valley for three or more years. Over the same period of time, a variety of annual and perennial plants have been screened for their ability to support these parasites around the perimeter of fields.

What laws govern the use of pesticides?

Pesticide Protection Laws in the U.S. Government regulation has banned a number of harmful pesticides but some scientists call for strengthening pesticide laws. The Environmental Protection Agency (EPA), the Department of Agriculture (USDA), and the Food and Drug Administration (FDA) regulate the sales of pesticides under the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA). The EPA has only evaluated the health effects of 10% of the active ingredients of all pesticides.

Reducing Exposure to Pesticides What Can You Do? Reducing Exposure to Pesticides • Grow some of your food using organic methods. • Buy organic food. • Wash and scrub all fresh fruits, vegetables, and wild foods you pick. Figure 13.30 Individuals matter: ways to reduce your exposure to pesticides. QUESTION: Which two of these actions do you think are the most important? • Eat less or no meat. • Trim the fat from meat.

Class Discussion Do the advantages of using synthetic chemical pesticides outweigh their disadvantages? a. No. Synthetic pesticides are overused, damage the environment, and increase cancer risks. b. Yes. Pesticides save human lives and protect crops.

What is Integrated Pest Management?

Other Ways to Control Pests There are cultivation, biological, and ecological alternatives to conventional chemical pesticides. Fool the pest through cultivation practices. Provide homes for the pest enemies. Implant genetic resistance. Bring in natural enemies. Use pheromones to lure pests into traps. Use hormones to disrupt life cycles.

Other Ways to Control Pests Biological pest control: Wasp parasitizing a gypsy moth caterpillar.

Other Ways to Control Pests Genetic engineering can be used to develop pest and disease resistant crop strains. Both tomato plants were exposed to destructive caterpillars. The genetically altered plant (right) shows little damage.

Case Study Discussion Read the Case Study: Integrated Pest Management: A component of Sustainable Agriculture. Answer the discussion question at the conclusion of the Case Study.

Case Study: Integrated Pest Management: A Component of Sustainable Agriculture Integrated Pest Management (IPM) An ecological approach to pest control uses a mix of cultivation and biological methods, and small amounts of selected chemical pesticides as a last resort.

Case Study: Integrated Pest Management: A Component of Sustainable Agriculture Many scientists urge the USDA to use three strategies to promote IPM in the U.S.: Add a 2% sales tax on pesticides. Establish federally supported IPM demonstration project for farmers. Train USDA personnel and county farm agents in IPM. The pesticide industry opposes such measures.

Class Discussion Should governments heavily subsidize a switch to integrated pest management? a. No. Without extensive funding and training, mere subsidies are not enough to successfully promote integrated pest management. b. Yes. These subsidies would decrease pollution and exposure to hazardous pesticides.

How has the development of preservatives impacted food?

Mini-Project Research one natural preservative and one artificial preservative. Create a fact sheet on the following information: Describe the differences between the two types. What types of food are associated with your examples. Explain the positives and negatives about each.

What impact does foodborne illnesses have on the U.S.?

Foodborne Illness What impact does foodborne illnesses have on the U.S.? U.S has one of the safest food supplies in the world. Each year 76,000,000 people get sick from foodborne illnesses. 300,000 people are hospitalized 5,000 people die More dangerous bacteria in our food today than we were aware of in 1942. May become sick in 20 minutes to 6 weeks after eating food with harmful bacteria. Who is prone to foodborne illnesses? Infants and young children, pregnant women, older adults, and people with weaken immune systems

E. coli O157:H7 Outbreak From Fresh Spinach Case Counts by State (As of October 6, 2006) Source: http://www.cdc.gov/foodborne/ecolispinach/case_count_us_map.htm

Foodborne Illness What outbreaks of illnesses have occurred in our state? http://www.cdc.gov/foodsafety Why be concerned about food safety? About 50 percent of the money spent on food goes toward food prepared by others. Much of the food today comes from around the world, where food sanitation may be lacking. Resistant bacteria are on the rise. In 1950, five foodborne pathogens were known. In 2002, this number had grown to 25.

Bacteria What is bacteria (pl) or bacterium(s)? Single cell microorganisms, of which some are beneficial to man and others are harmful. Bacteria that are harmful to man are called pathogens. Bacteria are found everywhere. How many bacteria would exist after 24 hours from a single cell division? They multiply rapidly through binary fission; one cell can double in 20 minutes.

Bacteria How can food become contaminated with bad bacteria (pathogens)? Animals –droppings and saliva or disease microorganisms within the animal. Thus if food is not properly cooked, foodborne illness can occur. Soil – contaminated animal droppings that are transferred to plants, thus if the plant products are not cleaned or cooked properly, foodborne illness can occur. Water – contaminated animal droppings come in contact with water, and water is consumed or sprayed on crops. Humans – food contaminated with hands that are not clean.

Bacteria What do bacteria need to grow and reproduce? Nutrients – bacteria, like people, need many of the same things that humans need to grow Moisture – bacteria need moisture to grow and reproduce. They may exist on dry food and surfaces, but nothing will happen until moisture is introduced. pH- bacteria grow well around a 4.6 pH. That is why acidic foods tend to be safe from pathogenic bacteria. Temperature – bacteria grow rapidly in temperatures between 80-105 degrees F. Proper cooking and chilling slows the growth of bacteria. Time –bacteria can multiply rapidly, sometimes two to three times per hour

Lab Microbiological Analysis of Food Lab You will apply the elements of scientific inquiry to solve a multi-step problem. You will examine the presence of bacteria on food. Generate a question about food and bacteria. The source of bacteria may not be from the human body (ex. saliva – double dipping) and no rotten food (ex. spoiled meat). Evaluate the appropriateness of question. Can you effectively test a hypothesis? Design an investigation with adequate control and limited variables to investigate a question. What is your control, independent variable, and dependent variable? Organize experimental information using analytic and descriptive techniques. How will you collect data? Evaluate the significance of experimental information in answering the question. Project additional questions from a research study that could be studied.

Mini-Project You are the owner of a restaurant. After a recent outbreak of food poisoning at local restaurants, you want to make sure your employees are knowledgeable on food safety. Create a pamphlet containing the following information: Two common types of food borne illnesses. Include the cause and the symptoms. General Guidelines for the safe handling of food. Ways to tell if food is safe. Suggested resources: CDC and USDA

Discussion Questions Globalization of the food supply –Imported and exported foods will only increase in the future. How can the regulatory agencies handle this increased activity? How can countries work together to protect and provide a safe food supply that is traded between countries? Increase use of organic foods – Production and the demand for organic foods will continue to grow. The general impression is that organic foods are safer, but that is not always true. How can producers of organic foods minimize the possibility of pathogens contaminating their foods and what precautions should consumers take with organic foods? Changes in food consumption –Increase in ethnic food demands and consumers eating more fruits and vegetables pose problems. Raw and fresh vegetables and fruits (that are eaten uncooked) have a greater chance for dangerous pathogens to be consumed by the public. How can the public be educated on the safe practices for eating fruits and vegetables? At-risk subpopulations – As the numbers of elderly population grows, a group more susceptible to foodborne illnesses, and the technology for organ transplants develops further. How should people and businesses directly involved in the food chain change their practices?

Discussion Questions con’t… Pathogen evolution –Microbial evolution has always and will always occur, meaning that health and regulatory agencies must continue to monitor the food supply chain to assure safe foods. How will society pay for this continual expense? Consumer understanding – All participants in the food supply chain must accept the responsibilities and risks that are associated with safe foods. How can young children be educated on the safe practices for the safe handling of foods? How can adults be reminded of their responsibilities? Integrated food supply –The farm/ranch to table food supply and safety system is a complex system and involves many different environments, people, and businesses. What role and responsibility can each of you assume in this system to help assure safe food for yourself and others? Identifying all foodborne pathogens – The number of diseases caused by pathogens is more than 200 and it is still growing. How can society keep ahead of these new evolutions? Controlling the worst pathogens –It is difficult to determine the worst pathogen. Should researchers focus on a pathogen that affects a low number of people, but is deadly, or on one that affects a large number of people, but is not deadly?

Review Key Questions How can we protect food resources from pests? What are the environmental effects of producing food? What laws govern the use of pesticides? What is Integrated Pest Management? How has the development of preservatives impacted food? What impact does foodborne illnesses have on the U.S.?