Mary loved having her own garden and would often spend many hours tending to its care. She was meticulous in watering the plants, pulling the dreaded weeds, and harvesting the fruits and vegetables as they ripened. Her garden consisted of corn, tomatoes, greenbeans, okra, zucchini, squash, lima beans, watermelon, and cantaloupe. Often, the garden would produce much more than Mary andher daughter, Sue, could eat. Rather than waste the delicious food, the ladies would spend hours on the weekend canning the excessvegetables and fruit. It was something they had done for many years. On this particular occasion, Sue noticed that the pressure cooker, the instrument used to sterilize the canned food, did not seem to be acting quite right, but the cans were hot when they came out soshe figured everything would be okay. Several months after their weekend of canning, the ladies invited the entire family over for Thanksgiving dinner. The meal consisted ofturkey, ham, chicken, macaroni and cheese, rolls, spinach salad, tomatoes, corn, lima beans, green beans, and okra. All of thevegetables were the ones they had previously canned from their garden. For dessert, they had pecan pie and vanilla ice cream. Thenext day, while most of the family was out shopping, four of the family members were home with blurred vision, dry mouth, and muscleweakness. Mary called the family physician, Dr. Franklin, who told her to take the sick individuals to the emergency room, and he wouldmeet them there. Upon arrival at the ER, Dr. Franklin asked what the family members had eaten for the meals before they developedthe symptoms. The common foods that all of them ate were the chicken, the ham, the tomatoes, the green beans, and the spinachsalad. The doctor determined that the family was suffering from botulism food poisoning. In the United States, foodborne botulismhappens in 15% of cases each year, frequently from foods with a low acidity. He was suspicious of the green beans and tomatoes, eventhough tomatoes are highly acidic. Dr. Franklin also said that using proper methods of microbial control could have prevented theirillness. Which of the following is an example of microbial control?

a. Sue washes off the vegetables before serving them in a meal.
b. Mary warms food up in a microwave before putting it on the table.
c. Sue uses bleach to clean the kitchen counters.
d. Mary places leftovers in the refrigerator after the meal.