Thursday, December 19, 2013

MMWR case study- Staph enterotoxin outbreak from food served at office party

In the Dec 20th edition of MMWR, a case study of a 2012 incident of staphylococcal enterotoxin poisoning is presented. The outbreak occurred at a military base where 13 individuals were admitted to the hospital after eating contaminated perlo (a chicken, sausage rice dish). According to the report, the 22 individuals became ill 2 to 3 hours after eating at a work lunch party. Symptoms included nausea, vomiting and diarrhea. While there were a number of dishes served, the investigation determined the perlo was the culprit. This item had been prepared the previous day, kept warm in an unheated oven overnight (8 hrs), and then reheated the next day.

Staphylococcus is commonly found on people and can contaminate food when properly handled. However, the key factor in this case was the temperature abuse, in this case, holding the food overnight in the unheated oven. During this time at the elevated temperature, the organism grows and produces the heat stable enterotoxin that is not destroyed during reheating. When the contaminated food is eaten, symptoms are usually seen within a few hours. If the perlo had been properly cooled, the organism would not have grown and would not have formed the toxin.

Keep this story in mind as you attend the various holiday parties this holiday season. It will make you wonder about who cooked each of the dishes and how good their food safety practices are.

 Outbreak of Staphylococcal Food Poisoning from a Military Unit Lunch Party — United States, July 2012
December 20, 2013 / 62(50);1026-1028

On July 30, 2012, the emergency department at a military hospital was visited by 13 persons seeking care for gastrointestinal illness with onset 2–3 hours after a work lunch party. The hospital responded by opening up temporary evaluation and treatment capacity in primary-care clinics and a progressive-care unit and by diverting one patient to a local civilian hospital. An immediate outbreak investigation was conducted by local military public health personnel with assistance from CDC. Initial epidemiologic analysis implicated "perlo" (a chicken, sausage, and rice dish) and bacterial intoxication as the outbreak mechanism. This enabled public health personnel to 1) recommend no further consumption of perlo and 2) reassure appropriate authorities that no additional ill persons likely would be seeking care and advise that nothing more than supportive care of ill persons likely would be required. After interviewing party attendees, investigators found nine additional persons who met their case definition. Subsequent CDC laboratory analysis of a sample of perlo detected staphylococcal enterotoxin A, supporting the epidemiologic findings. Improper food handling and preparation measures were identified and addressed by the appropriate authorities, who provided additional detailed education on food preparation safety for the persons who prepared the meal.

Epidemiologic and Environmental Investigation

Consumer Reports Chicken Report - Fear your chicken or Cook your chicken

Consumer Reports has just released a report on the safety of chicken, “The High Cost of Cheap Chicken”. This report is bound to get a lot of airplay.

There is little dispute over the fact that chicken can contain pathogenic bacteria…in fact, USDA on-going testing shows similar numbers. And while this report deals out some harsh treatment of your common grocery store chickens, it is important to note that even small farmed raised chicken can have pathogenic bacteria. In the Penn State study by Dr. Cutter and Josh Scheinberg where farmers’ market chicken were found to have a high prevalence of pathogens .

The CR report does point out good information: 1) no type/brand of chicken tested was really any better than any other in terms of the prevalence of pathogenic bacteria, and 2) that it is important for people to properly handle and prepare their poultry. This includes cleaning of surfaces that may have come in contact with raw poultry or their juices and that poultry be properly cooked to a temperature of 165ºF or higher.

But in this report, as well as in the mass media reports that followed, there is there over-the-top titles or commentary that will cause confusion among consumers. In the Chicago Tribune, there is “Superbug bacteria widespread in U.S. chicken: consumer group” and in Huffington Post, “Half of Supermarket Chicken Harbors Superbugs, Consumer Reports Finds”. Superbugs in my chicken…OMG!. The term ‘superbug’ is a loosely used term that generally is applied to organisms that are resistant to multi-antibiotics. The biggest concern for multi-antibiotic resistance organisms is in hospitals, where they can cause severe infections especially during surgery. But many of these species have not been shown to be a concern in food, outside of Salmonella. Antibiotic resistance is nothing new….it has been found in microorganisms that have never been exposed to antibiotics, so superbug status could have been applied to organisms long before antibiotics were used by people. And just having resistance to a few antibiotics is not as important as to which antibiotics the organisms are resistant. So the study, which is not a scientifically peer reviewed research (as far as we can tell), does not provide detail on these particulars, but rather throws out a generalized number that is latched on by the media without providing any qualifiers. So this nebulous term ‘superbug’ used in these reports does not advance the understanding of the general public, but rather serves to grab headlines through fear.

This is not to say that antibiotics should be used judiciously for animals. In fact the FDA is looking to put tougher restrictions on antibiotic use in food producing animals. As many farmers will point out however, antibiotic use is a lot lower than portrayed in the news media.

So yes, chicken can contain pathogenic bacteria. That is why it is important to properly handle it as well as cook it.

Monday, December 2, 2013

Deer hunters, be sure downed animal was healthy before eating venison

November 22, 2013

UNIVERSITY PARK, Pa. -- Food-safety specialists with Penn State's College of Agricultural Sciences annually issue warnings to deer hunters to keep food safety in mind if they are fortunate enough to get a buck or a doe, and this fall is no exception.

However, this year because of the discovery of chronic wasting disease in wild Pennsylvania deer, they are cautioning hunters to be sure their animal appears healthy.

Chronic wasting disease -- often called CWD -- is a chronic, degenerative neurological disease affecting the central nervous system of animals such as deer and elk. The disease has been moving east in recent decades.

"In the past year, three free-ranging deer harvested by hunters in Blair and Bedford counties were found to have the disease," said Martin Bucknavage, senior food safety extension associate in the college's Department of Food Science. "While there is no evidence that supports CWD being linked to human illness, the U.S. Centers for Disease Control and Prevention does recommend against eating meat from deer infected with the disease."

Bucknavage noted that it is best to take precautions, such as making sure the deer you killed appears to have been healthy, and to follow best practices for handling and processing deer, such as wearing rubber gloves and minimizing contact with brain and spinal cord material.

"While the risk of CWD is very low, hunters need to focus on the overall safety of the meat. This starts from the time the deer is downed until it is processed and cooked for eating," he said.

"Each year we hear stories of people who get sick a day or two after getting a deer, most often from cross contamination, the result of not handling the raw meat properly."

Bucknavage urges hunters to do the following:

-- Carry a pair of rubber gloves with you when hunting and then be sure to wear them when field dressing the deer.

Deer carry pathogenic bacteria, and so precautions are needed to prevent cross contamination, he pointed out. "Whether you get blood on your hands or clothes or not, be sure to wash thoroughly in soap and water after handling the carcass or the meat."

-- Eviscerate the animal as soon as possible. This helps the carcass dissipate heat and removes internal organs where spoilage can occur more quickly.

Be sure to avoid cutting into the internal organs, especially the intestines. There are large numbers of bacteria -- including pathogenic bacteria -- in the intestines. "Tie off the anus," he said. "This can be done with a string or rubber band."

-- Evaluate the internal organs of the deer during field dressing. If any of the internal organs smell unusually offensive, or if there is a greenish discharge, black blood or blood clots in the muscle, do not consume the meat.

"If you kill a deer and question the safety and quality of the meat, immediately contact the Pennsylvania Game Commission," Bucknavage said. "The agency has policies for authorizing an additional kill."

-- The brain, spinal cord, spinal column and lymph nodes of deer are considered high risk for CWD, so avoid cutting into those tissue when butchering. If possible, hang deer by hind legs with head down when aging or butchering.

"Most cattle and livestock processed in this country are hung with the head down," Bucknavage said. "That prevents brain and spinal fluids from contacting the meat."

-- Remove all visible hair, dirt, feces and bloodshot areas from the internal cavity. Wipe the inside of the body cavity with a dry cloth or paper towel. If you rinse the cavity, be sure to dry thoroughly. Excess moisture will encourage bacterial growth.

-- Be sure to clean residues from knives and equipment, then sanitize with a chlorine bleach solution. It is wise to carry sanitary wipes with you to clean knives in the field.

If the outside temperature is greater than 40 Fahrenheit (F), you can help to chill the carcass by inserting plastic bags of ice or snow into the body cavity. Once out of the field, get the carcass into a cooler or refrigerator as soon as you can. If the temperature is below 40 F, prop open the cavity with sticks to promote cooling.

Don't tie the deer to the hood of your car. This will serve only to heat the carcass.

Because of the possibility of pathogens on the meat, such as E. coli O157:H7 and Salmonella, it is important to properly cook the meat to a minimum internal temperature of 160 degrees F or higher before eating.

The USDA guidelines are available online through Penn State's Food Safety website. The Department of Food Science offers hunters a wealth of information on the preparation of wild game from the field to the table.

The Field Dressing Deer Pocket Guide explains how to field-dress a deer safely. Extensively illustrated in full color, it explains the process of field dressing and also covers important food-safety information for hunters. See it online.