Does lime juice make raw seafood, ceviche, safe? Sorta

Queensland has fabulous limes.

They taste nothing like the American ones, and I buy them by the bucket.

I’m a late arrival to the virtues of limes – odd that I have Limey heritage – but now they are in everything: the gallons of fruity herbal tea I drink daily, water Tahitian-Limewith ice and lemon-lime-ginger bitters, lime butter for popcorn and seafood, you get the idea.

I have a Tahitian lime tree on my concrete balcony, with dreams of someday moving near the ocean and properly planting my tree.

A boy can dream.

The acid in limes has long been used to marinate or cook raw fish in ceviche. But does it really make seafood safe?

Prateek Mathurand and friend of barfblog, Don Schaffner, report in this month’s Journal of Food Protection that lime juice does reduce levels of Vibrio, but is not so effective against Salmonella. I’ll stick with lime and a mild heat treatment for any seafood. Raw is risky.

Effect of lime juice on Vibrio parahaemolyticus and Salmonella Enterica inactivation during the preparation of the raw fish dish ceviche

Journal of Food Protection, Number 6, June 2013, pp. 928-1108 , pp. 1027-1030(4)

Mathurand, Prateek; Schaffner, Donald W.


Ceviche is a raw fish dish common in Peru and other Latin American counties. The most characteristic feature of ceviche is the use of lime juice for marinating or “cooking” the raw fish. Confirmed cases of cholera in Peru, New Jersey, and Florida have been associated with ceviche. Although the effect of organic acids on pathogenic bacteria has been well characterized, few data exist on the effect of these acids in seafood systems. The objective of the study was to evaluate the effects of lime juice marination on pathogens likely to be present in ceviche. Tilapia (Oreochromis niloticus) fillet pieces were inoculated with Vibrio parahaemolyticus and Salmonella enterica (>7 log CFU/g) and fish.bbq.feb.13incubated at 25 and 4°C for 30 or 120 min in the presence of fresh lime juice at concentrations typical for the preparation of ceviche. Similar levels of cells were also inoculated into fresh lime juice without tilapia. Surviving cells were enumerated on selective (xylose lysine Tergitol 4 and thiosulfate-bile-citrate-sucrose) and nonselective (tryptic soy agar) media. V. parahaemolyticus levels were reduced to below detection limits (∼5-log reduction) under all conditions studied. Salmonella strains on tilapia were much more resistant to inactivation and were only slightly reduced (∼1- to 2-log reduction). Salmonella and V. parahaemolyticus inoculated directly into lime juice without tilapia were all reduced to below detection limits (∼5-log reduction). A typical ceviche recipe reduces V. parahaemolyticus risk significantly but is less effective for control of S. enterica.

My Brisbane bromance – with citrus

This is me and my new brofriend, Gary, and a disgruntled Amy at a Rush concert (not exactly as show, below). I don’t even like Toronto-based Rush, even though they played at my Brantford, Ontario high school when I was in grade 9 or something. They probably were experimenting with 2112 at the time.

No, what saddens me is when Dr. Pepper screws up limes. I didn’t really get the whole limey thing before, but after being to the U.K. and living in Brisbane, I get it. Those scurvy-infected sailors had no citrus (eat local in Scotland).

So Gary took me plant shopping at the market last Sunday and, even though he’s a kiwi, he taught me a new Aussie term: SNAG – sensitive new age guy. This is what you buy for a townhouse with no ground but lots of balconies, at the market in spring — lemon tree, tahitian lime tree, lemon basil, rosemary, youngberry, blackberry mulberry, and strawberry.

Dr Pepper don’t know HACCP

Sometimes, when Amy is feeling nostalgic, she’s go to the Americana section of the grocery store in Australia and buy a Diet Dr. Pepper for, oh, about $2 a can.

The US Food and Drug Administration (FDA) has warned Dr Pepper Snapple Group (DPS) bottler the American Bottling Company after an inspection revealed serious HACCP failings at a Texas plant.

Beverage Daily reports that in a letter to the company dated July 10, but published last week, the FDA said an inspection of the firm’s facility in Irving, Texas revealed serious violations of Regulation 21, Code of Federal Regulations (CFR) Part 120, relating to juice hazard analysis and critical control points (HACCP).

“Your lemon and lime juices are adulterated in that they have been prepared, packed, or held under insanitary conditions whereby they may have been rendered injurious to health,” FDA Dallas District director Reynaldo R. Rodriguez wrote to American Bottling Company president and CEO Larry Young (who is also DPS CEO and president).

Recounting “serious deviations” at the site, the FDA told the managers that the company must include control measures in its hazard analysis and HACCP plan to “consistently produce at a minimum, a five-log* reduction of the pertinent microorganism for at least as long as the shelf life of the product when stored under normal and moderate abuse conditions.”

These were required under 21 CFR 120, the FDA wrote, but the company’s plan for its ReaLemon 100% Lemon Juice and ReaLime 100% Lime Juice brands did not provide such controls in relation to Listeria monocytogenes.

Only microbial verification studies relating to Salmonella and E.coli O157:H7 were evaluated, the FDA added, but “the pertinent microorganism in the juice from these concentrates is Listeria monocytogenes.”

“In addition, the study did not evaluate or identify the critical factors necessary for achieving a 5-log reduction (i.e. specific Brix, acidity, temperature, preservatives), and the time of holding necessary for achieving a 5-log reduction.”

Is that a tapeworm you have or are you just happy to see me; ceviche, to eat or not

Gonzalo Erdozain asks, what to do when tired of writing a research paper? Cook, and then blog about it.

The cooking in this case is a misnomer – I prepared ceviche. It has different iterations with varied ingredients, but as a food safety nerd, the one constant element of concern (which makes it ceviche) is raw fish “cooked” with lime juice. Eating this dish a few years ago would have been easy, but with three years of food safety research and two years of vet school under my belt, I just know a bit too much about the risks involved. Yet, here I am, preparing it.

Besides the well-known possibility of a bacterial contamination, like Salmonella (as in a recent sushi outbreak), Listeria (of special concern for pregnant women and immunocompromised individuals), or Vibrio, I happened to recall a parasitology lecture about Diphyllobothrium latum, a.k.a. broad tapeworm (although not a true tapeworm, we will call it that to spare you the details as to what qualifies as a true tapeworm).

D. latum is becoming more common in developed countries due to the increasing popularity of dishes based around raw fish (e.g., ceviche, sushi, sashimi). Doing some research, I found a paper where the acidity of the lime lowered the Vibrio numbers down to a safe level, while another study found lime acidity to have no effect on Salmonella. Listeria seems to be less resistant to acidic condition when kept at 7º C, and since ceviche is refrigerated for two hours while the fish “cooks,” the risk of Listeria could be reduced (I would still never feed this to a pregnant woman or immunocompromised individual).

Regarding the tapeworm, I didn’t find anything specific about lime juice, but the FDA makes the following recommendation:

“Parasites (in the larval stage) consumed in uncooked, or undercooked, unfrozen seafood can present a human health hazard. Among parasites, the nematodes or roundworms (Anisakis spp., Pseudoterranova spp., Eustrongylides spp. and Gnathostoma spp.), cestodes or tapeworms (Diphyllobothrium spp.) and trematodes or flukes (Chlonorchis sinensis, Opisthorchis spp., Heterophyes spp., Metagonimus spp., Nanophyetes salminicola and Paragonimus spp.) are of most concern in seafood. Freezing and storing at -4°F (-20°C) or below for 7 days (total time), or freezing at -31°F (-35°C) or below until solid and storing at -31°F (-35°C) or below for 15 hours, or freezing at -31°F (-35°C) or below until solid and storing at -4°F (-20°C) or below for 24 hours is sufficient to kill parasites. FDA’s Food Code recommends these freezing conditions to retailers who provide fish intended for raw consumption.”

I used cod, and found no evidence of it ever being involved in a tapeworm infection; but it could be possible. And if I end up with a tapeworm, I will let you all know. As for my kitchen clean-up, I did the same as when I deal with any raw meat: clean and disinfect all surfaces and stuck all utensils in my dishwasher.