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Food Safety Focus (167th Issue, June 2020) – Incident in Focus

Eating Undercooked Beef Burger or Steak Can Cause Food Poisoning

Reported by Ms. Melva CHEN, Scientific Officer,
Risk Communication Section, Centre for Food Safety

Consumers are advised not to eat undercooked beef burger or steak to avoid food poisoning
Figure 1: Consumers are advised not to eat undercooked beef burger or steak to avoid food poisoning.

Over the past few years, there has been a trend for gourmet-style burger restaurants in Hong Kong. Some consumers may prefer the taste and mouthfeel of rare or medium burger patties to those of their well-done counterparts. However, they may not be aware that undercooked burger patties can impose risks of food poisoning.

How Would You Like Your Beef Burger Cooked?

Burger patties should always be cooked well-done regardless of the quality, source and price of the meat. When meat is minced to produce burger patties, harmful bacteria such as Salmonella or pathogenic Escherichia coli (E. coli) from the raw meat's surface are mixed throughout the whole piece. Unless the burger patty is cooked right through, these bacteria can remain alive on the inside. Therefore, ground beef should be cooked until the internal temperature reaches at least 75°C or until browned throughout with the juice running clear.

Infection of Pathogenic E. coli from Undercooked Beef Burger Can be Fatal

The intestinal tracts of cattle is the main reservoir of pathogenic E. coli bacteria. One of the serotypes, E. coli O157:H7, may cause acute renal failure, particular in young children and the elderly. In 1993, E. coli O157:H7, linked to contaminated hamburgers from the Jack in the Box chain restaurants, infected hundreds of people in the USA. The majority of the victims were under 10 years old. Four children died and some victims were left with permanent kidney damage.

Despite the hard-earned lesson from the above incident, outbreaks associated with undercooked ground beef still occurred from time to time worldwide. In 2019, ground beef contaminated with another strain of pathogenic E. coli sickened over 200 people in the USA. In Hong Kong, there were also sporadic cases of E. coli O157:H7 infection linked to minced beef congee reported in the past.

Undercooked Steak Should Also be Avoided

Some people consider that steak can be just seared on the outside and not cooked in the middle, because they think that bacterial contamination is usually limited to the surface alone. Risk still exists nevertheless when consuming undercooked steak: all undercooked meat including steak may carry bacteria, and some bacteria may even carry antimicrobial resistance (AMR). AMR results in reduced efficacy of antibiotics, which results in more complicated infections that are difficult to treat. Consumers, especially young children, the elderly, pregnant women and people with a weakened immune system, are advised to eat thoroughly cooked steak (i.e. internal temperature reaching 75°C).

Many restaurants, especially the western-style ones, often let consumers choose the doneness of their steaks. There are nonetheless prerequisites should the steak be not cooked in full. For example, the steak to be served undercooked must be an intact meat that is not injected, mechanically tenderised or reconstructed, likewise being stored and handled according to strict hygiene practices. That said, overseas food safety authorities do not recommend eating undercooked meat. The UK Food Standards Agency, the US Department of Agriculture, the New South Wales Food Authority of Australia and Health Canada consider internal temperature reaching 63°C with a three-minute rest time is the minimum cooking requirement for intact beef or steak.

Provide Consumer Advice for Undercooked Meat

Restaurants that serve undercooked steaks are encouraged to provide consumer advice on their menus to inform consumers of the potential risk. The following is an example of consumer advice that restaurants can provide, whereas it applies to raw/undercooked high-risk food of all sorts:

"Consuming raw or undercooked foods may increase the risk of foodborne illness, especially for pregnant women, infants, young children, the elderly and people with weakened immunity.”

Key Points to Note

  1. Raw and undercooked meat may carry harmful bacteria including AMR bacteria.
  2. When meat is minced, harmful bacteria from the surface of the raw meat are mixed throughout the whole piece.
  3. Thorough cooking of meat including burger patties and steaks can reduce the risks of food poisoning and acquiring bacteria with AMR.

Advice to Consumers

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